It was a busy week for tornadoes, considering that it's January! Stu Ostro wrote a blog about the tornadoes on January 7. 49 tornadoes have been confirmed from the 7-8 January outbreak through damage surveys on Sunday, with 33 of those in Missouri. 31 tornadoes were confirmed on the 7th and 18 on the 8th, for the second-largest January tornado outbreak on record. Four of them were rated EF3. These were followed by at least 17 more confirmed tornadoes on January 10, with four rated EF3 in Mississippi and Alabama. The largest January tornado outbreak had 138 tornadoes on January 21-22, 1999.
From my perspective, the most remarkable aspect of these outbreaks has been several rare tornadoes. EF3 tornadoes struck northern Illinois and southeast Wisconsin on the afternoon of January 7. An EF1 tornado struck near Vancouver, Washington in Clark County on January 10.
The northern Illinois and Wisconsin tornadoes developed along a warm front, following an incredibly warm January night. Just south of the warm front some places in northern Illinois, including the Chicago area, set new records for warmest minimum temperatures in the month of January (in the low 50s). Still, this was WAY north of where tornadoes are typically expected in January!
The radar images below show the precipitation and velocity patterns of the supercell thunderstorm that produced the EF3 tornado that struck the Poplar Grove and Harvard areas of Boone and McHenry County, IL on January 7. The rotating portion of the supercell thunderstorm is circled in yellow. That rotating updraft -- called a mesocyclone - is shown by the green-red couplet. The tornado occurs right where the red suddenly changes to green -- the tight circulation area called the tornado vortex signature (TVS). Radar images are courtesy of the National Weather Service office, Milwaukee,WI.
To put the rarity into context, northern Illinois had only one previous tornado in January in records since 1950. The whole state of Wisconsin had only one previous reported tornado in January. Two were confirmed there on Monday! The first hit the Wheatland area near New Munster and was rated EF3. The second one was rated EF1 and hit the north side of Kenosha. The radar image below shows the hook echo depicting the swirling precipitation pattern with the supercell thunderstorm as it approached Kenosha. Superimposed weather data show a temperature of 63F (courtesy of NWS, Milwaukee).
Doesn't the pattern above look a lot like the one below, from south of Jackson, Mississippi on the evening of January 8? You can clearly see the counterclockwise-swirled shape of the precipitation pattern into a hook. No tornado has yet been confirmed from this storm, although a tornado warning was in effect (purple parallelogram). Mississippi is a much more typical place for tornadoes in January, and 8 have been confirmed there on January 8, along with 5 in Alabama, 1 in Louisiana, 1 in Tennessee, and 1 in Kentucky.
Probably the most unusual tornado on January 10, however, was the one that hit near Vancouver, Washington. The radar image below shows that storm, the southernmost storm in a small line, just north of the Oregon-Washington state line.
This tornado was from a totally separate, cold-cored storm system. The satellite image below shows the massive squall line (tall blue tops) associated with the tornado outbreak in the Southeast, and another weather system in the Pacific Northwest (with much lower storm tops). I've superimposed arrows showing the upper-level jet streams associated with each system.
The thunderstorm that spawned the Vancouver tornado fed off instability driven by a cold pocket aloft, centered just north of the jet stream. The surface temperature was only about 52F. By comparison, unusual to record warm air found on the southeast side of the jet stream spawned the tornado outbreak in the South. Different combinations of ingredients can spawn tornadoes!
The Vancouver tornado in Clark County, Washington was the first on record there in January. All 8 previous tornadoes in the county since 1950 has struck from April to October. An F3 tornado had struck the county on April 5, 1972, killing 6 people and injuring 300, not far from where Thursday's tornado struck. The whole state of Washington had only had two previous January tornadoes since 1950, and those were in 2000 and 2006. In recent years, the state of Washington has averaged about 4 tornadoes per year, mostly from spring through fall.
The growing number of rare to unprecedented tornado and severe thunderstorm events in far northern latitudes in this and recent winters makes me go "hmm." It is certainly enough to raise the possibility that global warming has already begun to affect tornado and severe thunderstorm climatology. On the other hand, Oregon and Washington have had tornadoes in November and December in the 1950s and 1960s. A tornado struck Illinois in January 1950 in Kankakee County, Illinois, within 90 miles of Monday's tornado. The rarity of tornado events makes it hard to prove that there's a trend -- and to disprove that there isn't one.
[updates follow original entry; latest as of 4pm EST Wednesday]
Is this January 7 or April 7?!
This report is from Wisconsin. In January.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
620 PM CST MON JAN 07 2008
01/07/2008 0415 PM TORNADO 3 NE NEW MUNSTER WI
STATE HIGHWAY 50 AND COUNTY HIGHWAY O. 12 HOMES DESTROYED...SOME WITH NOTHING BUT FOUNDATIONS LEFT. LARGE TREES DOWN. ONE THREE-FOOT ROUND OAK TREE DOWNED WITH A SMALL TRAILER WRAPPED AROUND IT.
There have been slews of reports of severe thunderstorms and tornadoes from Wisconsin to Oklahoma in this historic outbreak (and more severe weather to come on Tuesday), and here is the radar at this hour (9pm CST) ... and this is the kind of situation in which thunderstorms persist at night, not dissipate after sunset.
And oh what an evening it has been in Webster County, Missouri ...
6:39 pm CST
7:47 pm CST
8:32 pm CST ... not as eerily identical as the other two images, but very high "reflectivities" in the northwest part of the county, and there was some rotation indicated at this time. Portions of Greene County, the one adjacent to the west (in which Springfield is located), have also been hit hard this evening.
Webster County images: GRLevelX
UPDATE
10:15 pm CST, and another gigantic thunderstorm in Webster County ...
And, shortly thereafter, a whole train of 'em lined up to the southwest and moving northeast, creating a flash flood threat in the region in addition to everything else ...
UPDATE TUESDAY MORNING JANUARY 8
There was additional damage overnight; here is the preliminary list of severe weather reports from Monday and Monday night compiled by NOAA's Storm Prediction Center.
Hopefully there won't be as many tornadoes today, but with ample low, mid (map below), and upper-level jet stream energy interacting with the air mass which is unusually warm and humid so far north for early January, the threat for additional severe weather will continue to exist.
Already a report of a fatality from a tornado in Arkansas this morning about 55 miles due northwest of Little Rock, a couple of minutes prior to the time of that radar image. The green and red colors adjacent to each other show winds blowing rapidly in different directions a few thousand feet above the ground, indicative of rotation in the thunderstorm.
This illustrates the ongoing threat; weather.com's WeatherREADY pages have guidelines to help keep you safe ... and please keep attuned to the latest weather information, watches, and warnings ...
UPDATE 7PM EST TUESDAY JANUARY 8
Indeed, today hasn't been as prolific a tornado producer as yesterday was, but there have been a half dozen or so reports since sunrise as well as a bunch of reports of "straight-line" wind damage and large hail.
Meanwhile, damage surveys of yesterday's twisters have been in progress. That one in Wisconsin which I cited at the beginning of the original blog entry has preliminarily been rated a high-end EF3. And here's an initial National Weather Service map (subject to change) of tornado tracks in southwest Missouri -- look at what happened in Springfield!
[Click on image for full map.]
UPDATE 4PM EST WEDNESDAY JANUARY 9
This storm system wasn't done with its dirty deeds yet ... showers and thunderstorms with severe straight-line gusts blasted across the eastern Great Lakes and upstate New York early today, and strong "gradient winds" have continued.
Meanwhile, reports from the many tornado damage surveys going on continue to come in. The National Weather Service office in Milwaukee/Sullivan has posted some vivid photos; the ones below don't show the damage quite as clearly as the others (you can see them all here and at full size), but I've embedded these because they depict the essence of the rarity of what happened -- that location at this time of year -- with the pond still partially frozen and a pile of ice/slush in the foreground of the other photo.
Stu Ostro has written a blog with several updates as a monster storm hit the West, beginning late Thursday January 3, 2008. While it's still not totally done blasting that area, some of its impacts have begun to spread east and will continue to do so into early next week, reaching the East Coast on Wednesday January 9.
The storm packed intense winds, gusting over 60 mph in San Francisco and in the Sacramento Valley, causing power outages to about 1.5 million customers. On hill and mountain tops, winds were even stronger, with gusts over 100 mph reported in several places in California, Utah, and Nevada, even on hills less than 2000 feet high near Los Gatos (near San Jose). Gusts of 60 mph or more were reported in Washington, Oregon, California, Idaho, Wyoming, Nevada, Utah, Colorado, and South Dakota.
Combine those winds with heavy snow on the mountain tops and blizzard conditions prevailed that closed I-80 at Donner Pass, CA, and other roads. Up to 71 inches (nearly 6 feet) of snow has been reported in the Sierra.
But the point of my blog -- and hence its title -- focuses on the storm in the southern half of California. My title is meant to remind people that it's this kind of winter storm that brings the rains that enable millions of people to live in Los Angeles and other parts of southern California where desert conditions would otherwise prevail.
Winds in southern California weren't as strong as in northern California, but they were very moist and blowing strongly toward the south- and southwest-facing slopes of the mountains from near Santa Barbara to Los Angeles to northeast of San Diego. The horizontal winds blowing toward the mountains get angled upward along the slopes, with a substantial upward component. That component creates the clouds and heavy precipitation. So the stronger the winds blow in mountainous regions, the heavier the rains tend to be when there is a deep layer of moisture coming off the Pacific Ocean -- as in this case. This wasn't generally a record rain event, since some storms in previous years had stronger, more prolonged upslope wind components.
But this monster storm system brought 4 to 9 inches of rain to the mountain slopes of southern California on Friday through Saturday morning. There were reports of slightly over 9 inches of rain in Santa Barbara County, slightly over 8 inches in Ventura County, and about 7.5 inches in Los Angeles and San Diego Counties. Reservoirs in these areas collect the runoff in storms like this, and help provide water supplies to the valleys below. Similarly, snowpack generated on the mountain tops melts during the summer and helps restock the reservoirs during the normally dry summer periods.
Many of the recent years were dry in southern California, including a record-dry water year (July 1, 2006-June 30, 2007) in Los Angeles. Southern California and Nevada were in severe to extreme drought as this monster storm began. Los Angeles and San Diego, California and Reno, Nevada had less than half of their average rainfall for calendar year 2007. In helping increase the water supply for a drought-plagued region, the storm's heavy precipitation was largely a blessing.
The rains were a curse in some places, though, causing local flash flooding and mudslides. Probably the worst situation, though, was east of Reno, Nevada where a levee failed at Fernley, inundating most of the town and forcing the evacuation of about 4000 people. The snow level in this region was generally above 7,000 feet during the period of heavy precipitation, so a lot of the Sierra got rain rather than snow.
The impacts of this monster storm will still be felt into early next week. On Monday, the leading edge of the disturbance will begin to intersect Gulf of Mexico moisture. This could mean severe thunderstorms and possibly some tornadoes in eastern Kansas, Oklahoma, and Texas, Missouri, Arkansas, and Louisiana, and then possibly farther east across the Gulf Coast states on Tuesday.
Speaking of curses and blessings, the rain accompanying these potentially dangerous storms will again be welcomed in the Southeast, where exceptional drought continues. Several heavy rains during December helped a bit, but many places had yearly rainfall deficits of a foot or more, including over 31 inches at Tuscaloosa, Alabama. Some places had less than half of the average annual rainfall. Heavy rains on December 28 and 30 spared Atlanta from its driest year on record, taking second place by a paltry 0.05 inches. Huntsville and Birmingham, Alabama and Greensville, South Carolina had their driest years on record.
The late-December rains allowed the lakes that supply Atlanta, Georgia and Raleigh, North Carolina, for example, to rise between about two-thirds of a foot and two feet. The lakes are still way below normal levels (almost 19 feet too low in the case of Lake Lanier near Atlanta), so any rain that the monster storm can squeeze out will be welcome.
[updates follow original entry; latest as of 1AM EST Monday]
Lots of moisture and energy, that is (as can be seen on the satellite image above), racing from the western Pacific toward California, and also a huge warm-up across central and eastern North America.
There'll be a series of atmospheric disturbances pushing onshore from Thursday night through the weekend and early next week, with a particularly intense one coming Friday into Friday night. It'll bring heavy rain and strong winds to lower elevations of the West.
In the higher elevations of the Sierra, before all is said and done snow accumulations will be measured in feet if not yards. The Reno office of the National Weather Service has issued a statement with some historical perspective on big snowstorms of the past there.
Meanwhile, to the east of that, after the current surge of Arctic air the weather pattern for awhile will resemble one typical of April rather than January ... this is an "ensemble" model forecast for next Monday of temperature departures from average at 850 millibars, about a mile up in the atmosphere and a key level that meteorologists analyze ...
UPDATE THURSDAY AFTERNOON JANUARY 3
Still on track ...
On this satellite image with superimposed upper air analysis, the first system (yellow circle) can be seen arriving on the West Coast, with a second, stronger one (red circle) on its heels, and additional moisture and energy (green arrow) lurking upstream from that.
Ahead of the first system, winds are already picking up -- gusting to near 60 mph at Lake Tahoe Airport in South Lake Tahoe -- and what I forgot to mention in my original post yesterday was that winds could be really wild on the ridgetops in the Sierra through tomorrow, with the NWS warning of gusts upwards of 140 mph.
And a brisk southerly flow advecting in warmer air has kicked in all the way from the Gulf of Mexico to the Great Lakes and southern Canada.
By Monday morning, here are the forecast low temperature departures from average ...
UPDATE 9AM PST FRIDAY JANUARY 4
The picture is worth a thousand words, but here are a few more ... wind gusts of 50-70 mph being reported all over the place in lower elevations of northern and central California ... in fact many of you won't be able to read this until later because of power outages ... in higher elevations, if the measurements are accurate there have been gusts to 151 and 153 mph at 4438' and 5300', respectively, in Oregon and far northwest California ... wind and snow will now be increasing in the Sierra ...
UPDATE 1:30 PM PST FRIDAY JANUARY 4
Check out this satellite image from the University of Washington ... way too big to embed here (it's >5MB, and 3000x3527) ... but at full resolution and not resized in your browser, it shows great detail throughout the entire cyclone ...
Looking ahead, the energy from the series of Pacific storms will evolve in the central U.S. in a few days to interact with that big warm-up I've been noting to create severe thunderstorms and potentially tornadoes ...
UPDATE 7PM PST FRIDAY JANUARY 4
Per the University of Wisconsin CIMSS blog, there was an extreme satellite-derived wind estimate at the 258 millibar level (an altitude of approximately six miles) over the Pacific early Friday morning of 252 knots, which equals 290 mph. Even if the estimate was slightly off, there sure was a strong jet stream associated with this storm!
And here is the latest discussion out of the Reno NWS office:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
609 PM PST FRI JAN 4 2008
.MESOSCALE UPDATE...
NARROW COLD FRONTAL RAIN BAND HAS PUSHED THROUGH MOST OF THE RENO CWA AS OF 2Z...HELPING LOWER THE SNOW LEVELS TO VALLEY FLOORS. THE MAIN CONCERN OVER THE NEXT 3-6 HOURS ARE THE INSANE SNOWFALL RATES WE ARE SEEING...AT LEAST 3 INCHES PER HOUR WITH LOCALIZED RATES OF CLOSE TO 6 INCHES. WE`VE SEEN LIGHTNING STRIKES...THUNDERSNOW IN THE BAND JUST PUSHING THROUGH RENO-TAHOE RIGHT NOW.
LATEST RUC FORECAST SOUNDINGS SHOW THESE STEEP LAPSE RATES PERSISTING INTO THE OVERNIGHT HOURS. VISIBILITY DOWN TO 1/4SM IN HEAVY SNOW AT THE RENO AIRPORT...DEFINITELY A RARE OCCURRENCE. NUMEROUS FLIGHTS ARE BEING CANCELED. I-80 IS NOW CLOSED PER CALTRANS REPORTS AND ROADS AROUND THE RENO AREA ARE BECOMING TREACHEROUS. BLIZZARD CONDITIONS ARE WIDESPREAD IN THE SIERRA WITH ZERO VISIBILITIES.s
Also, heavy rain pushing into Southern California with the threat for flash flooding and mudslides overnight ... and this report from Montana:
INTERSTATE 90 HAS BEEN CLOSED FROM EXIT 330 TO 338 WITH COUNTY SHERIFF REPORTING MULTIPLE ACCIDENTS WITH AT LEAST 4 SEMI TRAILERS BLOWN OVER.
UPDATE 10PM PST SUNDAY JANUARY 6
The snowfall was indeed measured in feet and yards in the Sierra, and in addition to the above totals here is a list of many others including 4-5'+ at Northstar-at-Tahoe, from where TWC's crew was providing live reports. The most intense storm of the series pushed onshore on Friday, but there have been other rounds including one bringing locally heavy precip to SoCal tonight. Then additional storminess will move in from the Pacific to the northwest U.S. this week.
To the east, the temperature reached 73 degrees in St. Louis on Sunday, and it's still in the mid-60s in the middle of the night in the heart of winter. As the western energy reaches that balminess, intense thunderstorms will develop in the south-central states late Monday and sweep northeast on Tuesday, with the potential for another round on Thursday.
Another by-product of the warmth: widespread dense fog as the warm, moist air moves over melting snowcover. That has unfortunately resulted in two fatalities from vehicular accidents in Wisconsin along with many other injuries, and after having been closed in Montana a few evenings ago (see above), another stretch of I-90 has been shut down, this time east of Madison in the Badger State.
Last year at this time I posted an entry which contained satellite and radar highlights of 2006, so I figured I might as well do another one for 2007 -- the second annual! This time I decided not to restrict the images to radar and satellite, and rather than grouping them by type of weather, they're generally in chronological order ... with one notable exception: the image I've chosen as the most stunning of the year, which is at the end.
There was quite an array of weather this year ... in fact as I went back and reviewed it there were things I had forgotten about ... and devices such as satellites and radar and computers and cameras enabled the meteorological phenomena to be captured visually for the ages. The following is not meant to represent a complete list of every significant weather event everywhere or images thereof, but there's a lot of stuff which will bring back memories. What was most memorable weatherwise for you in 2007?
####
The year got off to a surreally warm start, with bees buzzing, flowers blooming, and maple sap flowing in early January ...
Below is a photograph that I took (with a cell phone camera, no less!), and thus it represents a personal memory rather than a significant weather event ... but I'll never forget seeing this in January over the Owens Valley in California with the Sierra escarpment in the background ... living in the eastern U.S., I had never observed such a spectacular "flying saucer" (mountain wave) cloud ... and it represents one of the things I was talking about in this recent entry on why meteorology exists ...
On Groundhog Day, a mobile home in Lake Mack, Florida is completely gone following a series of tornadoes which hit that community and others including Lady Lake, contributors to what would go on to be the deadliest year for tornadoes in the U.S. since 1999.
[Click on image for larger version]
The swath of purple represents an eruption of convection over and downwind of Lake Ontario, part of an epic bout of lake-effect snow in early February that ended up producing more than 100" in some places including 141" (!) at Redfield, New York, and mountainous snowbanks into which Mike Seidel frolicked during TWC's coverage.
On the heels of that came a storm (water vapor depiction thereof below) which on Valentine's Day and the days prior brought a variety of very inclement weather to a large area, including New York state again, where up to 42" of snow fell.
Meanwhile, the tornado season in the Texas panhandle and eastern New Mexico got off to an early start, with Clovis getting hit in late March, and then a few days before the Eagle Pass tornado the radar was lit up including with supercells which produced twisters in Cactus and Tulia.
Below is a satellite loop of the much-hyped mid-April "Patriots' Day Storm." A quick recap: Yes, it was big and bad, and as I said in my lengthy meteorological and philosophical analysis at the time, I don't want to minimize the suffering that occurred ... but public officials, meteorologists, and the media have a responsibility to make and communicate accurate assessments, and even after the storm there were pronouncements such as that it caused the "worst flooding in New Jersey in decades." Well, the official totals are now in, and the $ damage in my home state was ~105 million along with three fatalities and no other injuries reported. The damage there from Hurricane Floyd's flooding in 1999: $545 million, plus 6 deaths and 188 injuries.
This was an inconsequential but eye-catching (not only catching humans' eyes, but appearing to have one of its own!) little doohickey just offshore of Florida in late April ... and, in hindsight, an omen of what was to come during hurricane season. No, it wasn't a particularly bad year for the U.S. compared to the likes of 2004 and 2005, but the southeast U.S. coast and adjacent subtropical Atlantic was a focus of activity including many tropical, subtropical, and non-tropical systems.
Speaking of which ... soon came Andrea, which started as a strong and gigantic non-tropical cyclone which in tandem with a high pressure system to the north created a steep pressure gradient, strong winds, and monstrous waves, such as at this buoy:
And then after weakening, its circulation drew in smoke from the wildfires in parched Georgia and Florida:
[Click on image for large version]
The action shifted into southern Canada in late June, as the first tornado in that country to be rated an F5 struck Elie, Manitoba (Canada has not yet adopted the new EF Scale of tornado intensity) ...
[Click on image for larger version and copyright info]
Then ... the next day, severe thunderstorms erupted in southern Canada again including a cyclic tornadic supercell which moved from Saskatchewan into Manitoba ... and courtesy of Reed Timmer, here is a spectacular tornado video, which can be enjoyed because at the time the twister was in a very rural area and not hurting anyone or destroying property. You can see the tornado grow in size; darken and become dramatically contrasted with the backlight, reminiscent of the photogenic Dimmitt, Texas tornado in 1995; and then evolve into gyrating multiple vortices which become amazingly well-defined at 5:05 of the video.
Here are a couple of unusual sights. No, not because the close-up of the inner core of the tropical cyclone is so vivid -- although this one is particularly 3-D-ish, this sort of amazing-looking structure is often seen courtesy of high-resolution MODIS imagery when tropical cyclones become very intense. Nor is the second image out of the ordinary -- it's a type known as a microwave image which meteorologists utilize nowadays.
What was unusual is that the Category 5 intensity in the first image was over the Arabian Sea, and at the time of the second one, Gonu was still of hurricane strength as it headed into the Gulf of Oman.
It might not have rained for 40 days and 40 nights in a row last spring and summer, but folks in the central U.S. sure needed an ark at times. This was the 90-day precipitation total as of late July, and the rains kept on comin' for awhile after that.
At one point Iowa got blasted repeatedly by "northwest flow" thunderstorms, one of which produced this gigantic hailstone:
While the weather was stormy there in July, it was sizzling in Montana, and the heat transfered to many other states as August progressed.
This isn't something you see every day: a tornado-producing thunderstorm at sunrise in New York City! It occurred as the heat tried to surge into the Northeast, and the EF-2 twister was Brooklyn's strongest in the historical record.
Then Felix came onshore in Nicaragua, making 2007 the first year on record in which two Atlantic basin hurricanes officially made landfall as Category 5s within the same season.
This model forecast which showed Gabrielle developing, becoming a hurricane, and slamming into New York City helped some forecasters to get wiggy. The storm ended up limping onshore in North Carolina with minimal impact.
What's so notable about this one? Doesn't it show convection over the Gulf of Mexico having gone kaput?
Yes, and that's why I included it! Because despite there being nary a raindrop or puff of wind that evening, by the following evening the radar looked like this, a tipoff that what had quickly become a tropical depression and then tropical storm had the potential to further intensify, which it did, into a compact hurricane (Humberto) before making landfall later at night.
Two weeks later, deja vu in the Gulf of Mexico: another hurricane (Lorenzo) developing with astonishing rapidity, but with an equally remarkable size (tiny, which contributed to how fast the cyclone intensified, as small circulations can spin up or down quickly). Here's the surface map from when Lorenzo became a hurricane, showing nearly calm winds not far away from the center! Nevertheless, Lorenzo was potent enough to produce wind damage, flooding, mudslides, and six fatalities in Mexico.
The blue colors indicate that by late September La Nina was developing, leading to the usual sensationalism. Never mind that all the stuff depicted so far in this entry had already happened before La Nina!
Whether during El Nino, neutral conditions, or La Nina, each of which was present consecutively, it didn't matter -- 2007 was a wild year. The next example: the largest October tornado outbreak on record, and one which was unusually far north for that month. Here is a map showing where all the severe weather struck, and a radar image with three rotating thunderstorms lined up in a row (red/green "couplets") in Kentucky during the peak of the outbreak.
A week later, a particularly vicious Santa Ana windstorm with wind gusts as high as 100+ mph fanned the flames of a wildfire catastrophe in SoCal and even started fires by way of blowing down live wires.
The view from above and a commonplace scene from ground level:
Noel topped Felix as the Atlantic basin tropical cyclone causing the most fatalities, and only a couple of others including Katrina have been deadlier since Mitch nearly a decade ago. Here is Noel producing tragically heavy rainfall, flooding, and mudslides in Hispaniola.
Noel interacted with a large high pressure system to its north to produce a brisk and very persistent onshore flow in Florida. I'm sure some folks in the Sunshine State would want me to point out that the effects, on the heels of other events this year, weren't this bad everywhere on its east coast, but where Jim Cantore was the erosion was severe, and in general beach erosion in the Southeast was significant during '07.
Noel wasn't done yet; although officially non-tropical at this time, it sure looked as if it still had some "tropical characteristics," and the storm packed quite a punch in Cape Cod and Nova Scotia.
The cartoon which a viewer sent Steve Lyons and which helped lead to me doing a little wiggin' out of my own ... about hurricane seasonal outlooks:
The worst fatality count of the year from a single weather event -- more than 3000 -- was from Sidr. Of all the images available of the tropical cyclone, I find this one to be the most chilling. It shows the low-lying area of Bangladesh about to be struck, and it's almost as if the wisps of shadowy cirrus clouds high overhead are fingers of death advertising the cyclone's arrival.
The final month of the year came, and so did a storm that was exceptional even by Pacific Northwest standards because of its intensity, duration, and how far off the coast the low pressure center was during the height of the storm. This upper air analysis is representative of the huge "deep tropospheric gyre" which begat the onslaught and was south of a ridge of high pressure aloft of record December strength over northern Alaska and the Arctic Ocean.
Shortly thereafter: a historic ice storm. These are just a few of countless trees weighed down by the freezing rain in the central U.S. -- the same part of the country that experienced too much non-freezing rain earlier in the year.
Hmmm ... is that Olga regenerating into a tropical storm before making landfall in Florida in mid-December? Methinks so.
And, finally, the image which upon first seeing I stared at, speechless, and wondered whether what I thought I was seeing I was really seeing. Yes, it turned out, I was. Here's a view of the whole supercell and then a zoom on the portion to which I'm referring.
Although radar images can depict signatures that indicate the likelihood a tornado is occurring, conventional (as opposed to portable) Dopper radar generally does not "see" the actual tornado, but in this case it did because the twister that annihilated Greensburg, Kansas was so large in size and its circulation contained so much debris. Pieces of people's shattered homes and businesses, whirled into the sky by the tornado which was so strong that it got the first EF-5 rating on the stringent Enhanced Fujita Scale, contributed to the high "reflectivities" which show up as purple in the donut of destruction.
So as the year draws to a close and we head into '08 and wonder what the weather will bring next year, let's keep in our thoughts the folks in Greensburg and elsewhere who are recovering from the events of 2007 ... while at the same time we marvel at what the atmosphere is capable of and the images it and modern technology can create.
****
IMAGE CREDITS
(Some were embedded within the images but here is a complete list.)
I would like to be the first to wish you a Happy New Year! I hope your 2008 is healthy and exciting!
The weather has been active as of late and some spots are piling up the snow!
Denver's Christmas Record
The mile high city set a Christmas day snowfall record. 2.4 inches fell on December 25th. The old record was 1.7 inches set in 1912.
Boston is one inch away
For the month of December they have accumulated 26.9 inches, that's exactly 1" shy of the all time snowiest December on record. The record of 27.9 inches was set in 1970.
Salt lake city has a heavy snow warning
Salt Lake City needs 8" to tie their December record. They have 27.2 inches so far and their snowiest December on record was set in 1972 with 35.2 inches. There is a heavy snow warning and snow in the forecast through the end of the year!
So are you rooting for the snow or not? How has the snow affected your holiday travel? Does the weather affect your holiday travel? Do you always plan to go to a winter or beach location to ring in the New Year? Let us know your thoughts and we'll see you on TV!
Happy Holidays, everyone! And may your 2008 be healthy, happy, and safe.
The atmosphere has been putting up its decorations lately by depositing ice onto trees, power lines, and other things. This has made for pretty pictures, but unfortunately, also brought misery to many. I thought that I'd show three pictures, illustrating three different ways in which the atmosphere can deposit that ice.
The first picture is of clear or glaze ice. This develops when a long-lasting freezing rain or freezing drizzle event hits a region. On roads this is called "black ice." The rain and drizzle drops form an ice coating when they hit freezing objects, such as this tree. Thanks to Weather Warrior T. Henderson from Missouri for submitting this photo.
This ice is clear, nearly transparent, as these relatively large drops gradually build up coating on objects. Sometimes the freezing is slow enough that small icicles also hang down from horizontal objects where the water tries to initially drip while it freezes. The weight of the building ice coating can bring down trees and power lines and cause power outages.
In these ice storms, the rain drops either form in a warm layer aloft, or form initially as snow and then fall into a warm layer and melt, then fall into a sub-freezing layer near the ground and become "supercooled." That means they get chilled to below freezing temperatures but don't immediately become ice particles (which would be called sleet or ice pellets). The drops freeze on contact with objects at freezing or sub-freezing temperatures. Freezing drizzle drops can form in the same way as freezing rain -- but they have smaller diameters -- or can even develop in a below-freezing layer.
Rime ice is an opaque coating of ice that has a texture more like a crunchy snow and can be rough (as opposed to the smooth coating of clear ice). Thanks to Weather Warrior Teresa Thompson from Philadelphia, IL for submitting the picture below.
Rime ice forms from supercooled cloud or fog drops that are much smaller than rain or drizzle drops. The diameter of these drops is less than 0.004 inches (4 one-thousandth of an inch). They get air bubbles within and between them that gives the opaque appearance. This forms occasionally on mountain tops that stick up into the moving clouds and occasionally from freezing fog at other elevations. This kind of ice does not usually build up enough to cause power outages.
Frost is a layer of ice crystals that form on grass, trees, and other objects. Thanks to Weather Warriors Steve and Yvonne Nuttle for submitting the photo below from Tetonia, ID.
Frost forms as ice crystals are condensed (deposited) directly from water vapor in the air into ice crystals on some object. There is no liquid stage involved. Frost usually forms on clear, calm nights (no clouds or precipitation are involved) when air is moist and cools to below-freezing temperature near the ground.
Clear and rime ice can also form on airplanes that fly through supercooled clouds and/or precipitation. This can be a serious hazard and has caused deadly crashes, partly because of the extra weight of the ice and partly because the ice buildup interferes with the air flow across the wing and can reduce the lift force provided. Wing tips and other pointed leading edges of commercial aircraft have anti-icing devices to either melt or crack off the ice buildup. Clear ice is often more of a problem because it is harder to crack and because it sometimes runs back on the wing beyond the location of the anti-icing devices. Pilots try to avoid flying in layers of the atmosphere where icing is present.
Before taking off in winter conditions, aircraft undergo a de-icing "bath" with an antifreeze-type solution that melts off the coating of ice, snow, or frost. Stricter Federal regulations in recent years with regard to de-icing have cut down on the number of accidents.
This weekend's details have been much different from last weekend's. Instead of pesky cold arctic air ahead of the storm, this time there was a big warm-up in the eastern Great Lakes and Northeast leading to temperatures well above freezing in most places, and thus rain instead of ice or snow. On the cold side of the system, powerful winds on Saturday in the Plains accompanied bursts of snow and caused many traffic accidents and road closures.
As the front marking the boundary between the cold and mild air masses blasted through Chicago early Sunday morning, it was preceded by a line of "low-topped" convection that resulted in many reports of wind damage from that area across northern Indiana and southwestern Lower Michigan. Between that and the strong "gradient" winds prior to and following the cold frontal passage, the Windy City certainly lived up to its name! (But did you know that the average annual wind speed in Chicago is lower than in cities such as Boston, Dallas, and Honolulu?)
In weather, "convection" generally refers to showers and/or thunderstorms along with accompanying vertical motions in the atmosphere.
"Low-topped" means that the convection (and in this case mainly showers, not thunderstorms) didn't erupt up to a very high altitude in the atmosphere because the instability was limited. Below are a radar image from 2:27 am CST Sunday and a black-and-white infrared satellite image from a few minutes prior. Although the convection shows up very well on radar, it's barely visible within the circled area on the satellite image, especially in Indiana. The brighter the whites, the colder & higher the cloud tops; the more subdued grays are lower.
Nevertheless, all it took was some shallow convection to focus the wind energy and bring down many trees and power lines, some power poles, and even at least one roof blown off a building.
Though more sporadic, as the day wore on and the feisty weather pushed east there were a few additional reports of wind damage in the northeast U.S. as a result of yet another strong Sunday cyclone.
In a recent entry I cited examples of subtle and not-so-subtle snowstorms. For the second Thursday in a row there has been one of the former in the northeast U.S.
The satellite image above from Thursday morning which I've annotated is a classic, showing the main low pressure system way offshore but a surface trough extending back to another smaller but subtly potent circulation near the coast. (It wasn't necessarily as teeny as the "L" I put there, but I didn't want to cover up the cloud circulation details.)
Fortunately things didn't get out of hand, yet snow has accumulated 3-6"+ across central to southeast New England with a peak of 10-15" in a few locations in central and southern New Hampshire. Here are links to the latest totals from the Gray, Maine, and Boston offices of the National Weather Service.
Per this excerpt from a scientific study (I couldn't find the whole paper online) ... and what Jim Cantore has been saying for the past couple of days ... this was what's known in meteorology parlance as a "NORLUN" event ... and in this case it was a "Type II" ... wherein what is illustrated by that satellite image occurs ...
After 30 days with no tornadoes (November 15 -- December 14) and an unusually quiet November tornado-wise, suddenly the atmosphere kicked into tornado mode. Six tornadoes were confirmed in Georgia and Florida on December 15-16. Two more weather systems are on the way that could spawn others.
My two favorite aspects of meteorology are interpreting radar imagery and predicting severe thunderstorm and tornado outbreaks. I thought I'd share a little of each of those with you in this blog. The shapes of the radar echoes associated with some of the tornadoes were very interesting, and predicting winter tornadoes can be a challenge.
Four of the tornadoes on December 15 were spawned from the same thunderstorm or spinning thunderstorm complex as it crossed the region of southern Georgia near the warm front. The thunderstorm generally was within a kink or dog-leg within a line of thunderstorms across the area. This is often called a line-echo-wave-pattern or LEWP. The kink is associated with a small wave of low pressure.
The first two figures below show the radar echo associated with the first of the four tornadoes from this thunderstorm, which killed the driver of a tractor trailer that was tossed down a 50-foot embankment. It also destroyed four mobile homes and damaged 29 homes near Isabella, Sylvester, and Ashburn, Georgia. All radar images are courtesy of the National Weather Service.
The first image shows the thunderstorm in a comma configuration, called a mini-bow, with the head of the comma at the kink or dog-leg or LEWP that I was talking about. The tornado is forming near the leading, south edge of the comma pattern near the end of my arrow. A little red dot there indicates that a thunderstorm has formed just ahead of the bow and is about to merge with it -- a common mode of tornado formation in association with mini-bows.
The next image, from just 8 minutes later, continues to show the LEWP, but the tornado has slid north almost to the middle, leading edge of the bow, again at the end of my arrow.
The thunderstorm then began to look more like a low-topped supercell thunderstorm at times as it moved farther northeast and produced 3 more tornadoes. About an hour and a half later it was producing the last and strongest of these, an EF2 tornado near Lothair in Treutlen County, Georgia (just southwest of Soperton on the figures below). The first of the two radar images below show the tornado as a green triangle superimposed on the thunderstorm's precipitation pattern. The second image shows the tornado at the center of the tornado vortex signature (TVS) indicated by the Doppler velocity pattern. Winds toward the northwest are green, while those toward the southeast are red. Where they touch, the shifting winds are so close together that a tornado is suggested (the TVS).
The thunderstorm then swirled itself into a more linear configuration and was no longer tornadic. In fact, one that had a small-scale dog-leg structure within it as shown in the first of the pair of figures below. The rotation center is at the center of the center of that S-pattern near the "a" in Swainsboro, Georgia. Note that the red-green velocity couplet is much more widely spaced than before, indicating the larger, non-tornadic rotation that has developed within the thunderstorm.
As I mentioned briefly earlier, this thunderstorm was rolling along a warm front. It's shown in the figure below, in red. That separated air in the 70s from air in the 50s, along with quite a shift in wind direction from south to northeast. The converging components of the winds helped intensify this thunderstorm, while the shifting winds gave it a source of rotation. Thunderstorms south of the warm front did not have these two "bonus" factors.
Note also that the thunderstorms in south-central Georgia were well ahead of the cold front (blue). These thunderstorms were within a plume of tropical moisture associated with the remnants of Tropical Storm Olga, centered over the eastern Gulf of Mexico. Stu Ostro has written more about that feature in a separate blog.
With just 6 tornadoes, things could have been a lot worse -- considering that tropical moisture and unseasonable warmth were involved. But the middle- and upper-air trough, shown by the U pattern in the black lines below, fortunately was too far to the west of that tropical moisture. Its axis was from east Texas to west Iowa. So the cold air aloft near the trough axis (-30C in south Oklahoma) did not have a chance to move over that low-level warm tropical air and produce tremendous instability. Instead, the instability remained weak and few tornadoes formed. The map below is from about the 19,000 foot level.
The challenge of predicting winter tornado outbreaks usually involves that interaction. Where will the warm, moist, unstable air be? Will the upper-air trough and its cold air overtop it? Often, as was mostly the case on December 15-16, the upper-air system stays back in the cold surface air and promotes a snowstorm.
What about the upcoming weather systems? One is on tap for Wednesday night and Thursday, December 19-20. The second is for Friday night and Saturday, December 21-22. Let's take a brief overview of the numerical model forecasts for them. These model forecasts were generated on the morning of December 18.
The figure below shows the 500 mb map (near 19,000 feet) for the morning of December 20. I've superimposed the surface low (red L) and warm and cold fronts onto that map. Here there is no doubt that the upper trough and its cold pocket aloft are going to run right over the warm air between those fronts. But there isn't much room there, so the areal coverage of severe thunderstorms should be fairly limited to Louisiana and possibly parts of east Texas and Mississippi.
The next map shows the 500 mb pattern for the morning of December 22, again with surface low and cold front superimposed. The warm front doesn't seem like it will be too well defined in these forecasts, so there is a question of how far north the warm, moist, unstable air will get, ahead of the cold front. The strong part of the upper trough is nearing the front from Arkansas northward, so unless the unstable air gets as far north as Tennessee, there may not be much interaction of the warm low-level and cold upper-level air in this case.
At the moment I'm forecasting limited amounts of severe thunderstorm activity on December 21-22 for extreme east Texas, Louisiana, east Arkansas, Mississippi, west Alabama, and the Florida panhandle. But I'll be watching to see whether or not that forecast needs to change -- if the amount of interaction differs.
Well, if it looks like a duck and quacks like a duck (although this one was a strange bird) ...
In my entry on the large, dynamic, and complex weekend storm, I included info on The Return of Olga, and in my final comment on it alluded to its "landfall" in Florida as being very interesting and deserving of its own entry. As promised, here it is; in fact, as I've had time to go back and look at the data and imagery it's become even more intriguing ...
That cluster of thunderstorms morphed during the next couple of hours and reached another severe peak, which resulted in damage in Seminole and Volusia counties in the form of downed trees and power lines as well as a similar appearance on radar.
Turns out the situation that produced this had quite a history ... 'twasn't as simple as being a couple of typical supercells produced by an ordinary setup ...
At first glance, the convection as it approached the coast, with an embedded "LEWP" (line echo wave pattern, highlighted in image), appears to be just an unremarkable prefrontal squall line (although there's a hint of a spiral nature to the rainbands to the east and northeast) ...
The feature which eventually went over the jail had rotation which was already clearly evident while offshore. Here is a Doppler radar "velocity" image from 3:37 am EST on Sunday. The green/red "couplet" shows winds rapidly blowing in opposite directions a few thousand feet up in the atmosphere above the Gulf:
So far, nothing out of the ordinary ... but ... here's the pressure graph from Clearwater Beach!
Source: National Data Buoy Center; click for larger image
The pressure dropped to 1002.9 mb, consistent with that of a typical low-to-medium strength tropical storm. For example in the past couple of years, the pressure at time of Ernesto's landfall in Florida in 2006 was 1003 mb and with Tammy in 2005 it was 1002 mb, and Gabrielle had a central pressure of 1005 mb upon reaching the North Carolina coast in September 2007.
And here are the wind observations at Clearwater Beach, showing a rapid (but not sudden) rise to 40 kts sustained (46 mph), with a peak gust of 68 knots (78 mph) ...
There were other wind reports in the Tampa area that were sustained near tropical storm force (34+ kts / 39+ mph), and many measurements of gusts up into that range, along with pressures that dropped to below 1006 mb ... and data also shows that the cold front had still not caught up yet. Even though the low was embedded in a pressure trough and wind shift, and the temperature/dewpoint dropped slightly as the convection came through, the air was still relatively tropical, and the cooler & drier air mass did not decisively arrive until a bit later.
And although the accompanying storm surge was minor (peak generally ~2' above astronomical tides) given that that the wind field was not comparable in size or strength to that of a large hurricane, there was a noticeable jump (circled) in water level as the center/trough went by and the wind shifted. Here is an example at St. Petersburg. The green line on the first graph represents the departure from the normal astronomical tide; on the second graph the wind arrows point in the direction toward which the wind was blowing, and the higher on the graph they are, the stronger the winds.
Source: NOAA/NOS/CO-OPS
Per my blog as this was unfolding over the Gulf, and as can be seen by the series of satellite images below, the convection (even though it was shrinking by the time it reached Florida) and the surface low were clearly associated with the remnant Olga circulation.
Friday afternoon 12/14:
Saturday afternoon 12/15:
Infrared images from 2pm Saturday to 5am Sunday:
What needs more study ... the strangeness that I alluded to at the beginning of this entry (aside from the fact that this tropical cyclone redevelopment occurred in the Gulf of Mexico in mid-December!) ... is the nature of the small-scale details as the system came onshore, given that the lowest pressure and strongest winds measured (at Clearwater Beach, if the pressure measurement there was accurate) were south of the supercell-ish circulation which hit the jail and which moved onshore about 15-20 miles north of Clearwater Beach.
Also, the satellite imagery shows that the initial flare-up wasn't entirely directly due to the circulation itself, but rather was connected to the mid-latitude system. During that initial phase Saturday afternoon and evening thunderstorms brought flash flooding and tornadoes to south Alabama and Georgia, respectively, and then as the night progressed the deepest convection coalesced around the remnants of Olga, which regenerated.
We'll have to wait and see how the National Hurricane Center classifies this phase of Olga in their final post-event analysis ... but whatever the official assessment, this was yet another one of the infinite varieties of meteorological phenomena that the atmosphere is capable of producing!
[updates on wintry storm and remnants of Olga follow original entry; latest as of 12:15am EST Monday]
What do the snowstorms of Thursday and this weekend have in common with two of the most notorious tornado outbreaks of all time?
Well, one thing that has always fascinated me is the way that high-impact weather events can be produced by atmospheric signatures that run the gamut from dramatic to very subtle.
With tornadoes, you never know literally until the last second how bad it's going to be in terms of how many, exactly where, and how much property damage and how many casualties. But we could see the huge potential of the 1991 outbreak many days in advance, even with the relatively less-advanced numerical weather forecast models of 16 years ago. There was a large and powerful upper-level trough crashing out across the heart of the Great Plains, overhead of warm, moist air streaming up from the Gulf of Mexico.
I don't have an upper-air chart from the time of the peak of the outbreak, late that afternoon and evening on 4/26/91, but here are two from NOAA from the morning before and after, showing an immense trough crashing out across the central U.S.
By contrast, the upper-level signal was MUCH more subtle with the 1994 Palm Sunday outbreak. On the comparable map below, from just a few hours before the unusual morning outbreak began, there's nothing that jumps out. I'll never forget, though, hearing there was a tornado watch in effect for parts of Alabama and Georgia (I was off from work and this was before the days of a ubiquitous Internet), and standing outside in the Atlanta area that morning, feeling the stiff summery wind out of the south and seeing the sprouting cumulus, and thinking, "Uh-oh" ...
The same thing goes for snowstorms. On Thursday, there was a mess as heavy snow fell in a swath extending across southern New England, and people en masse left work early, creating huge traffic jams. Boston received ~10" of snow, yet the atmospheric signal was very subtle, with a weak low skedaddling off to the east at the surface and just a slight wavy wiggle aloft (circled below). The overall situation was very straightforward, though.
Now, this weekend, we're facing the polar opposite: a dramatic signature aloft with a sharp trough (a model forecast for Sunday afternoon is below) and a strong jet stream, and a large and hugely complicated storm system with a wild variety of weather, and forecasts that are difficult in some places insofar as the details of how exactly much snow will fall depending on how much warm, dry air aloft comes in, such as in parts of New York state.
What's certain is that the colorful display on the current radar map below will spread northeast and winds will increase as the barometric pressure in the storm drops, with everything from rain (after snow) and gales on Cape Cod (from where Mike Seidel will be reporting on Sunday) to heavy snow and blowing snow in Lower Michigan (Jim Canore's location) to a poutpourri of precipitation in between and an overall raw, cold, nasty day. I can't possibly provide detailed information within this blog for everywhere -- for that you can enter your location in the local weather box on the top of this page and always get the latest from TWC -- but I will provide updates on the overall situation as it unfolds.
Oh, and one more thing ... this would be a big storm regardless ... this is not like the Perfect Storm (in the same year as the Andover outbreak) wherein a dying hurricane played an important role ... but yes, that swirl over the Gulf of Mexico on the "visible" satellite image shortly before sunset is the remnant of Tropical Storm Olga, and the clouds streaming north are representative of just a little extra dose of moisture and energy feeding into the not-so-subtle/simple atmospheric paroxysm unleashing itself farther north.
UPDATE 1AM EST SUNDAY
Jim Cantore began his reports Saturday evening from Troy, Michigan, in the northern suburbs of Detroit just southeast of Pontiac. That location got some "bonus" snow which will factor into their total amounts, as a result of a "mesoscale" band of heavier precipitation. This occurred well out ahead of the main area of snow which is expected to affect the Detroit metro area from the wee hours through the first part of the day Sunday.
We often see those sorts of small-scale features set up during snowstorms, but predicting them farther ahead of time than as a "nowcast" is difficult if not impossible. Here's a radar from around the time of his last live report for the night, illustrating how it was snowing so hard there at the time and not so hard just a short distance north and south of the band.
... the remnants of Olga are acting up over the Gulf of Mexico! Per the visible satellite image from Saturday afternoon in my original entry above, and one from Friday, that big blow-up is definitely associated with the remnant circulation.
Ex-Olga is also becoming linked with the cold front approaching from the west via a pressure trough and wind shift ahead of the front ... and eventually the front will catch up and merge with it ... but for now the remnant is a distinct feature.
I'm not sure whether the 40 knot northwest wind ob (four barbs) below from 10pm EST is legit -- sometimes ship observations are coded incorrectly -- and it's unclear whether spin evident on radar centered about the "x" is associated with a mid-level center exactly collocated with a surface center ... but the 30 knot wind (three barbs) was measured at a buoy and, whether due to the "center" going by or just the prefrontal trough, has since veered around to blow from the WNW, sustained at 38 mph (33 knots), one mph shy of tropical storm force, with gusts to 47 mph ... and there is a surface low with a pressure down to at least ~1007 mb.
Whatever "it" is (the National Hurricane Center hasn't yet issued any special statements), it's getting picked up by the large mid-latitude system and is accelerating toward the ENE. If the convection stays robust until the system "makes landfall" on the west coast of Florida overnight, it'd bring heavy rain and gusty winds, and there's a threat of isolated tornadoes. Also, prior to the wind becoming westerly and onshore, water levels on Florida's west coast are running 1 - 1 1/2' above astronomical tides.
UPDATE 2:30PM EST SUNDAY
So, am I exaggerating when I say this storm is a big sprawling complicated mess?
It's about to become a bit less labyrinthine, though. Here's how it appears on water vapor imagery and a surface pressure analysis, which boil down all those complex details to show the storm's overall two-pronged nature: the upper low to the west, which up until this point has had underneath it the primary surface low, and the coastal portion, whose surface low will intensify rapidly starting now. By tonight that one's pressure, which was ~995 millibars (29.38") a few hours ago and now is in the mid-980s, will have further plummeted all the way down through the 970s and maybe even into the 960s. With that will come a tightening of the "pressure gradient," and it's going to be quite a windy night tonight and day tomorrow in the northeast United States and southeast Canada!
As for what ended up happening with the remnants of Olga early today, well well well ... I think that'll deserve its own entry, which I'll get to as soon as I can ...
UPDATE 12:15AM EST MONDAY
It's quite a low pressure system now, with the coastal one having taken over and the pressure in the middle of it continuing to plunge -- down to 28.68" or 971 millibars at Bar Harbor, Maine -- and the storm's pressure may go down a few more millibars before the low starts to "fill." A caveat about the NOAA pressure charts in this entry is that the isobars, or lines of equal pressure, are analyzed every 1 mb, rather than 4 millibars like on many weather maps, and the wind velocity has not rivaled that of Post-Noel, but there have been some gusts reported above 50 mph with sporadic damage.
Many locations in the Northeast had a combination of snow, ice (sleet and/or freezing rain) and rain. To the west where it was all snow, "9" was the magic number in Detroit. The nine inches of accumulation officially moved this snowstorm up to a tie for the 9th biggest one on record there in the month of December, with Detroit weather records going back to when Ulysses S. Grant was President of the Unitled States (1871)!
And Jim Cantore, after being awakened by thundersnow at 5:00 in the morning Sunday, later got a taste of the snow -- literally, as he was hit by this snowball during a video report (don't worry, it was all in good fun, in fact as he admitted in the video, it was staged) ... and you know that having been in Boston on Thursday, Jim was lovin' it being in the middle of a big snowstorm for the second time this week!
OK, I have a question for you Weather Channel viewers and blog readers out there. I know we all have our own favorite colors, opinions, tastes, styles, likes, dislikes, habits, etc. On things I have passion for I am very opinionated, whether I like it or not, that's just the way I am. As a scientist I try to allow all the facts and information to weigh-in/be absorbed into my brain before I have an opinion on something, but my personality processes that information selectively! I have never found an unbiased person in my life, unless of course they have "no opinion" on something...uh, oh, I guess that might mean they don't care about the topic, which is a bias to someone who cares deeply about that same topic! Hence, my "opinion" that no one is unbiased.
Well what I would like to ask you is a simple question, namely;
WHAT DO YOU LIKE TO SEE FROM LIVE FIELD COVERAGE OF A LANDFALLING TROPICAL CYCLONE?
I have strong opinions (biases) on these questions, but don't want to sway your opinion before I get yours. I "think" my opinion/bias very closely depicts your opinions, which is why I have them. But I really want to know for sure. Please be honest and think carefully how you score each question, you may have to go back a few times and adjust the scores. Whether you give a 10 or 5 is not important to me, rather which questions are rated highest and which are rated lowest (the relative weighting of the questions) is most important to me.
I give below (in no particular order) 10 choices; please rate them from 1-10, 1 being lowest priority and 10 being highest priority that you want to see on The Weather Channel. If you can use other TV-station examples as a guide for you to give the best answers, that is fine with me.
I don't want to bias your comments with my "bias" list, so please feel free to add choices to the list and rate the ones you add as well.
If I get a large response, it could end up helping get what you want to see during these events. And if I get a reasonable number of responses from you, J.Q. Public, I will post the statistics as a response to this blog. So, please participate or this will be a meaningless waste of time!
Just to clarify, I define "live field coverage" to mean coverage only from our guys/gals live out in the storm/hurricane/snow.
WHAT DO YOU LIKE TO SEE FROM LIVE FIELD COVERAGE OF A LANDFALLING TROPICAL CYCLONE?
Please rate them from 1-10, 1 being lowest priority and 10 being highest priority.
1) Graphics/history of tropical cyclones that have struck an area
2) Showing how people are preparing for a potential strike
3) Weather graphics shown by the live field reporters
4) Live video of unfolding impacts (waves/wind/rain/damage)
5) Broad, panning views of what is going on live
6) Close-up shots to better see the field reporter
7) Questions and answers from studio w/field reporters
8) Forecasts of the cyclone by field reporters
9) Live coverage of structures damaged by the event
10) Live coverage of structures that survived the event
If you care to post comments for any of questions feel free to do so.
Well, of course weather exists on Earth regardless of whether humans are present, but what about our study of it? I answer that question from my perspective in an article I wrote for Weather and Society Watch, a publication of the Societal Impacts Program at the National Center for Atmospheric Research (NCAR). With their permission I have reprinted it below, as I thought it would be of interest to readers of The Weather Channel blog.
First, though, I wanted to take the opportunity to also say a few more words about the subject of societal impacts and people involved in its study. A bunch of folks are endeavoring to integrate the social sciences into meteorological research, and during the past year I've had the pleasure of interacting with some of the scientists involved. It's been a rewarding experience for me as I get to know them and become more familiar with their work.
In addition to the Societal Impacts Program I mentioned above and the American Meteorological Society's Board on Societal Impacts, there's an initiative known as "WAS*IS"; that's a clever play on words involving both what the acronym stands for, which is Weather and Society * Integrated Studies, and the words within the acronym itself, which refer to addressing "societal impacts in real and sustained ways to change the culture from what WAS to what IS the future of integrated weather studies." Since 2005 the WAS*IS program has conducted a number of workshops in an effort to facilitate this as well as pull together people from the government, private, and academic sectors in the spirit of the "Fair Weather" report by the National Research Council of the National Academies.
While producing the most accurate forecasts possible has always been and should forevermore be an essential goal of meteorology, there is an end game, which is providing information that is effectively communicated, well understood, highly valued, and utilized to people's benefit.
For example, what are the best ways to:
-Convey uncertainty?
-Reduce vulnerability to weather extremes and climate change?
-Transmit alerts for hazardous weather phenomena? And then how does the spectrum from emergency managers to transportation officials, school superintendents, and parents effectively use those warnings to make life-or-death decisions or simply run their everyday activities?
And how can physical and social scientists with different responsibilities and backgrounds work together to answer these questions and achieve optimum results for society?
These are the sorts of issues that are explored in this arena. Even with all the advanced technology that exists in this modern meteorological era, there are still too many weather-related fatalities every year (and we've seen examples of that in the U.S. and elsewhere recently), and even when not in a dangerous situation, weather/climate and life are intimately and inexorably connected (and that includes animals and plants as well as humans).
If you'd like to learn more about the NCAR Societal Impacts Program and WAS*IS, their websites are here and here, respectively (and there's contact info on the WAS*IS site for any meteorologists, climatologists, or social scientists interested in attending the next workshop, tentatively scheduled for summer 2008); the latest and previous issues of Weather and Society Watch are here ... and here is that piece I wrote for it ...
Stu Ostro has blogged about the ice storm that formed as warm, moist air was lifted over and above a stalled front. Because there are quite a few weather stations in the Dallas-Fort Worth Metroplex, I thought it would be a fun opportunity to show you how sharp that front became there.
The image below shows the situation at 3 p.m. CT on Tuesday, December 11. On top of the radar -- with reds showing the strongest shower and thunderstorm cores and purple indicating very light rain -- I've plotted some weather data from the time along with the front position (blue line).
Ahead of the front, winds (arrows) were from the south and temperatures were in the 70s Fahrenheit. Behind the front, the temperatures dropped quickly into the 50s and winds were from the northwest. Farther to the northwest, temperatures dropped into the 30s and 20s (off the map, not shown). Fronts are located on the warm edge of the cold air mass, as drawn.
This front was actually behaving like a warm front earlier in the day, having pushed northwestward part of the way across the Metroplex. Temperatures rose in Dallas as the warm air mass pushed in but held almost constant in Fort Worth where the cold air mass held its ground. So at this time more than a 20-degree temperature difference had built up between Dallas and Fort Worth.
The winds colliding from nearly opposite directions helped sharpen the front by squeezing the two air masses closer together. That strong convergence also produced upward motion that helped trigger the line of thunderstorms almost along the front, shown by radar above. These thunderstorms are tapping warm air right from the surface there. We call those "surface-based." Surface-based storms usually have a larger chance to become severe.
Previously, as Stu mentioned in his blogs, the thunderstorms were well north of the front. Those "elevated" thunderstorms were forming in the warm layer aloft, not tapping air from near the ground below. On some occasions elevated thunderstorms produce hail, but they usually have less chance to produce damaging winds and tornadoes than their surface-based counterparts. That is because of the "protective" effect of the cold, stable layer of air near the ground below them.
The cold air layer west of the front was only about 2,000 feet deep at Fort Worth. The diagram below indicates how the temperature varied with height earlier that morning, about 5 a.m. CT. These are measurements from a weather balloon released from near DFW International Airport near the center of the Metroplex. Air temperature at the surface was 10C (50F), then got warmer as the balloon rose upward (green line moves upward and to the right). At about 2000 feet above ground, the temperature was 17C (63F). That's the bottom of the warm layer, being lifted above the front overtop of the Metroplex.
That warm air aloft was producing the precipitation that I've labeled "elevated post-frontal showers" on the diagram. In this region the cold layer wasn't below freezing, so north-central Texas got rain from this storm. But farther north, where the cold layer was below freezing, they had a devastating ice storm in parts of Oklahoma, Kansas, Missouri, and Iowa.
The resorts have all been doing very well lately with big snowstorms. I love to hit the slopes but sometimes find myself in an awkward position. I like to ski and snowboard. This is a big no-no. You have to be one or the other.
The problem is, skiers hate snowboarders and snowboarders couldn't care less about skiers. I end up causing a rift between my skiing buddies because they ski and don't want to be seen with a snowboarder. I can't convince them to try snowboarding so I end up have to ski only. That's cool but I would like to snowboard sometime too. Maybe I just need new friends. Any suggestions on what I should do?
I recently wrote about the confusing scientific jargon one must know to totally understand tropical storm and hurricane watches and warnings. I mentioned to you that all that really matters is what it can do to you, not what we call it.
Well, here is a little reinforcement for that argument. Today we have a newly named cyclone, Subtropical Storm Olga." Olga has just moved across Puerto Rico. I will not get into the definition of subtropical vs. tropical here; rather, I want to show you how two weather events can be very similar in character, but end up being called something very different.
Remember Hurricane Noel; it moved north just off the southeast U.S. coast, offshore North Carolina, just east of New England and then blasted Nova Scotia. But as it did so, there were no tropical cyclone advisories out on it; it had lost its name. It had been "classified" as a non-tropical low pressure circulation. So what I want to show you is a comparison of Subtropical Storm Olga and the non-tropical low pressure circulation that had been Noel (Noel's remnant).
First, satellite images below depict clouds and (based on the color coding of those clouds) the clouds' depth in both circulations. Note that both circulations had deepest convection north of a well-defined low/mid cloud center (Noel's remnant center ESE of Cape Hatteras and Olga's center just west of western Puerto Rico).
Neither had cloud tops that were extremely cold/high; hence, we see no purple colors in the clouds as we typically would for an "average hurricane." The overall shape and cloud patterns of both circulations are very similar; if I were to have blown up the much smaller circulation that is Olga they would look like twins.
Now let me show you the winds in and around each one estimated from the same Quickscat satellite (thanks NOAA). In this case I show them at identical scales: 100 miles is the same size on both images. Note that winds near and around the immediate periphery of Olga are light, strongest winds are well northeast of the center (northeast of Puerto Rico where the gradient in pressure is strengthened by high pressure over the southwest North Atlantic).
Olga has a well-defined circular wind pattern, but so does the remnant of Noel. Comparing the remnant circulation that was Noel, winds near its center are stronger, its strongest winds are closer to its center of circulation than are Olga's, and its winds are much stronger (many winds of 65-70 mph) than Olga's winds are (one wind of 40-45 mph). Olga's strong winds are confined to north of the circulation. Noel's remnant winds are much more symmetric, showing strong winds northwest, east and southeast of its center.
So you ask, why then is Olga a subtropical storm with tropical storm warnings up for the coast of the Dominican Republic while the remnant of Noel can be found only in a non-tropical high seas storm warning? The far more dangerous one to the U.S. and many other locations was of course the remnant of Noel.
The answer to this question is simple. It is a judgment call by the National Hurricane Center based on numerous scientific criteria they base their naming decision on. Relative to impacts, Olga is producing very heavy rains over Puerto Rico that will spread toward the Dominican Republic tonight. We already know the impacts from Noel's remnant along the U.S. East Coast and Nova Scotia (they effective felt hurricane winds and waves of at least 35-40 feet).
My point to all of this is simple. Perhaps you would be better off reacting to weather events based on a cyclone's danger to you, not based on what it is or is not called. Keep an eye on The Weather Channel's tropical cyclone "impact graphics" throughout every hurricane season; they don't include what a cyclone is called only what it can do to you!
In addition to what had already happened in a number of states, early Monday morning during the wee hours a line of that "elevated convection" I explained in my first entry on the ice storm developed over central Oklahoma and then things got out of hand. A wave pattern in the line formed, with a bulge on its rear end causing downpours of freezing rain to persist until the line finally moved away. This took place right smack over the Oklahoma City metro area, with the Will Rogers airport receiving 1.58" inches of rain in one hour between 3 and 4 am CST while the temperature was below freezing.
2:59 am CST Monday
3:23am CST Monday
Much of that rain froze on contact with trees and powerlines, and this contributed to what's being reported to be the largest power outage in Oklahoma history.
Although Oklahoma City's temperature has snuck above freezing at the moment, areas to the north are still solidly below; precipitation is on the increase again over northern Oklahoma and Kansas, with some strikes showing up on the lightning data, indicative of the instability aloft which still exists and could lead to intense precipitation rates again later tonight into Tuesday in some places. As is the case with phenomena such as severe thunderstorms and flash flooding, where the worst occurs depends on small-scale details, but many locations will at least get some freezing rain, and it'll be affecting areas that have been largely spared thus far.
Here is some good advice from the Kansas City office of the National Weather Service, as they state in their ice storm warning which is currently in effect for the region:
MAKE SURE YOU HAVE AN ADEQUATE SUPPLY OF FOOD. CHECK FURNACES AND FUEL LEVELS. DO NOT RUN GENERATORS IN ENCLOSED AREAS! IT IS NOT SAFE TO OPERATE A GENERATOR IN YOUR HOUSE...OR EVEN IN AN ATTACHED GARAGE. THE EXHAUST FROM THE GENERATOR CONTAINS CARBON MONOXIDE...A DEADLY GAS THAT IS BOTH COLORLESS AND ODORLESS. GRILLS AND STOVES DESIGNED FOR COOKING SHOULD NOT BE USED TO GENERATE HEAT INDOORS AS THESE DEVICES ARE NOT DESIGNED FOR PROLONGED USE AND ALSO PRODUCE CARBON MONOXIDE.
SIGNIFICANT AMOUNTS OF ICE ACCUMULATIONS WILL MAKE TRAVEL DANGEROUS OR IMPOSSIBLE. TRAVEL IS STRONGLY DISCOURAGED ONCE THE FREEZING RAIN BEGINS. MAKE SURE YOUR CAR IS WINTERIZED AND IN GOOD WORKING ORDER AND CARRY ALONG A SAFETY SUPPLY KIT THAT INCLUDES FOOD... BLANKETS AND A CELL PHONE. ICE ACCUMULATIONS AND WINDS WILL LIKELY LEAD TO SNAPPED POWER LINES AND FALLING TREE BRANCHES THAT ADD TO THE DANGER.
Also it's best to have a working flashlight with batteries (candles can start fires).
UPDATE 2AM EST TUESDAY
Have you been watching the past couple of days and wondering why The Weather Channel has kept Mike Seidel in the Kansas City metro area even though the bulk of the ice storm has been elsewhere? Well, here's one reason why:
We've been expecting the nasty weather to move into this and other places which had not yet received much ice since the light glaze on Saturday, plus the idea was for Mike to be a regional reporter given that the storm has been so widespread (unlike "chasing" the eyewall of a hurricane) and travel conditions have not been conducive to him moving around.
The radar shows how the ice storm slammed into KC Monday evening. Decoding the weather observation, it says that at Kansas City International Airport (MCI), at 8:53 pm CST (0253 UTC), shortly after the time of the radar image, there was heavy freezing rain (ZR+) with a temperature of 29 degrees.
That 29 degree reading at night (none of the sun's radiation making it through the clouds) is cold enough to cause ice to rapidly build up on trees and power lines. Every degree counts in situations like these, and there was a tipoff earlier today that a problem was looming.
Here are two models' forecast temperatures (part of what's known as model output statistics, or MOS) from Monday morning. The times are in UTC, so subtract six hours for CST. One model predicted the temperature to be teetering on the edge of the melting point all night at 32 degrees, while the other had it consistently above freezing throughout the night at 33.
But ... at 18 UTC (noon CST) the forecasts were for 31 and 28 degrees, yet the actual temperature turned out to be 25. Then at 21 UTC (3 pm CST) the models' predictions were 36 & 32, but when 3:00 came around the thermometer was reading 28 degrees. So it was clear that, as often is the case in a situation like this, the dense cold air near the Earth's surface was stubbornly hanging on, and trouble was a-brewin'. Also, by mid-late afternoon it was evident that the precipitation was coming in more quickly than the models predicted.
At this hour the temperature has crept up to 31 at MCI, but it still has two more degrees to go to get above freezing, and a significant amount of icing has already occurred in the KC metro area tonight as well as in other locations in northwest Missouri, Kansas, extreme southeast Nebraska, and southern Iowa. There's plenty of additional precipitation yet to fall, with thunderstorms erupting in West Texas being indicative of additional moisture and energy getting ready to swing northeastward. How severe the ice storm becomes in any given spot will be determined by the exact temperature there. A couple degrees difference either way with temperatures in the 70s doesn't matter much, but in a situation like this it sure does!
UPDATE WEDNESDAY AFTERNOON
Fortunately the temperature eventually got above freezing for awhile in most places on Tuesday, turning the freezing rain to just plain rain, but the cleanup and recovery will be ongoing for awhile, and I'll second the comments which show appreciation for those working to restore power ... I say that as someone who knows first-hand what it's like ... my house was w/o electricity for three days after one of the ice storms which hit Atlanta in January 2000 (not the one during the weekend of the Super Bowl -- that caused travel problems but there was one which was worse for trees and power lines the prior weekend).
Yes, indeedy, there's a system heading west toward the Caribbean. No wonder, with such a strong subtropical ridge bringing weather to the southeast United States that feels more like September than December.
Although the National Hurricane Center stops routinely producing their tropical weather outlooks on November 30, the "official" end of the season, they started issuing special statements on this system yesterday. Significant development is unlikely; at the moment it's somewhat disorganized and whether NHC officially classifies it as a tropical or subtropical storm at some point is uncertain, but one thing that will have to be monitored is the potential for locally heavy rain in the northern Caribbean Islands, including the Virgin Islands, Puerto Rico, and Hispaniola, with the latter still recovering from the deadly effects of Noel.
Although the bulk of the solid convection remains offshore for now, locally heavy showers are affecting Puerto Rico, where the NWS has issued a flood watch (also in effect for the Virgin Islands).
On St. Thomas, the wind gusted to 48 mph earlier this morning, not within any convection/rain. (The sustained winds were 25 mph at the time.)
UPDATE 9PM EST MONDAY
We have Subtropical Storm Olga, which has officially been declared as such by the National Hurricane Center. This is as a result of a well-defined surface circulation developing, and the system overall becoming better organized, even though it's still assymetric with most of the convection on one side of the center.
Significant intensification wind-wise is not expected, but that's immaterial for the primary risk, which continues to be from flooding. Latest radar shows the main rain area rotating into Puerto Rico, with the Dominican Republic and Haiti next in line. Fortunately the whole system is moving steadily along, but all it takes is a short period of intense rainfall rates to be deadly, so hopefully folks in the northern Caribbean are attuned to the threat.
UPDATE 5PM TUESDAY
There have been mudslides and flooding in Puerto Rico ... no fatalities reported yet, and hopefully that'll continue ... and now the rain area is moving into the Dominican Republic. The strength (wind-wise) and organization of the storm have peaked and from this point on should be on a downhill trend. Olga does not have the same oomph that Noel did, so hopefully there won't be the same outcome, but given how easily it is for deadly impacts to occur in the countries of Hispaniola when moist low pressure areas such as this interact wth the topography, the rain threat needs to be taken seriously just in case.
To Jim's and Shawn's questions, of the few tropical or subtropical cyclones which have formed in December, the only other one to do so during the satellite era in the tropics south of 20N and anywhere near land was Odette in 2003, which hit Hispaniola, and was a bit earlier in the month. Most of them have formed out in the middle of nowhere, such as the most recent one which was Zeta, which formed in late December 2005 and persisted into January '06.
So while there might have been other similar circulations that didn't get classified as tropical or subtropical storms by NHC, at least as far as the official historical record is concerned Olga is the latest to develop during the satellite era in this part of the basin.
Prior to the satellite era, in 1954, Hurricane Alice formed in the eastern Caribbean in late December and lived into January.
There has been one tropical storm in February, in 1952, and one hurricane in March, in 1908, though ya gotta wonder what they'd have been classified as in today's era.
UPDATE 8PM EST TUESDAY
The National Hurricane Center has now officially changed the classification of the storm from subtropical to tropical. Says NHC:
DATA FROM A HURRICANE HUNTER PLANE INDICATE THAT THE STRONGER WINDS ARE NOW CLOSER TO THE CENTER SUGGESTING THAT OLGA HAS TRANSITIONED TO A TROPICAL STORM.
UPDATE 5PM EST WEDNESDAY
Alas, while not of the catastrophic magnitude of Noel, there are reports of seven fatalities in the Dominican Republic from flooding, and one in Puerto Rico. This NOAA visible satellite image from a little while ago this afternoon before the sun set shows that while it's over in PR, deeper rain clouds persist over Hispaniola and some of them are moving into Cuba and Jamaica, even though winds with Olga have decreased and it has been downgraded to a tropical depression.
[updated as of 1am EST Monday, following original entry]
Well, maybe not quite fire, but I'm sitting outside in the Atlanta area while blogging and it sure is warm! Unfortunately, though, the strong subtropical ridge of high pressure responsible is also fending off the rain we so desperately need.
The other half of the title -- ice -- is definitely not an exaggeration, as people in parts of Kansas and thereabouts who have been in vehicular accidents today can attest to, even though most of the freezing rain which has fallen so far has been quite light.
There's more inclement weather in the offing, with a mixed bag increasing overnight in the south-central states, pushing across the Midwest Sunday and into the Northeast Sunday night & Monday, then another precipitation potpourri affecting the southwest and central U.S. Monday night into Tuesday. All the while, it'll continue feeling September-ish in the Southeast.
This is the temperature map from mid-afternoon Saturday:
72 degrees in Memphis and 32 in St. Louis -- you don't need to be a meteorologist to deduce that there's a front in between!
Here's the problem: the cold air near the front is very shallow, cutting under an above-freezing layer and leading to precipitation falling through the warmer air, melting, and then refreezing if the surface temperature is below 32F. S-SW winds aloft (arrows below) are bringing warm moist air in over the top of the icy cold, and are also blowing parallel to the front so it isn't moving much and the pattern is persisting.
Do you know the difference between hail, sleet, and freezing rain? If you don't, you're not alone. Here's the scoop:
The balls of ice which can become quite large and are typically associated with intense thunderstorms are known as hailstones.
Sleet also refers to ice pellets, but they remain small and only fall when it's cold out -- the wintry precipitation that goes ping ping and bounces around when it hits.
Freezing rain is nastier than sleet; it's rain which doesn't refreeze until reaching the Earth's surface. When accumulating heavily, that's what brings down tree limbs and power lines, but even a slight glaze on roads and sidewalks can be very hazardous. Be especially wary of "black ice," so called because sometimes a thin, virtually transparent layer of ice is invisible so drivers think they're just seeing a dark-colored roadway.
As can be seen by that graphic, just a sliver of above-freezing air typically results in sleet, and a thicker warm layer favors freezing rain.
Check your local weather on weather.com for the latest TWC forecasts and National Weather Service advisories, watches, and warnings, and if you're in the messy zone, please be aware of dangerous travel conditions!
UPDATE 6:45AM EST SUNDAY
Elevated training convection developed overnight. In other words, even though the air near the Earth's surface was cold, that warm moist air above let to instability aloft, and an atmospheric trigger coming in from the southwest helped ignite it; plus, the convection (heavy precipitation and even thunderstorms) has been traveling over the same places like train cars on a track because of that setup I described yesterday with the steering flow being parallel to the front.
Here are radars from within the past hour. In the top one Kansas City is in the upper left corner, and St. Louis is in the lower right of the bottom. These are not images of "winter weather radar," i.e. they don't differentiate between precipitation types by color, but I've included them because they show the detail of intensity very well. Some of this is sleet or just plain rain -- but in a narrow zone where the precip is all freezing rain it must be getting pretty nasty.
UPDATE NOON EST SUNDAY
Yep, it got pretty nasty, as indicated by this set of storm reports from southwest Missouri and southeast Kansas. For example:
ICE STORM COLUMBUS
12/09/2007 CHEROKEE KS LAW ENFORCEMENT
AT LEAST THREE QUARTERS OF AN INCH OF ICE ACCUMULATION. 100S OF POWER LINES AND TREES DOWN ACROSS THE COUNTY. DOWNED POWER LINES HAVE SPARKED TREE AND HOUSE FIRES. ALL ROADS ARE IN POOR DRIVING CONDITION.
UPDATE 11PM EST SUNDAY
'Twas another temperature classic today, from an afternoon high of 80 degrees in Shreveport to 25 in Springfield, Missouri. Although the small-scale temperature details will vary from day to day, esp. near that tight gradient with the front, overall WYSIWYG well into this week with that subtropical ridge not budging. In the Southeast, restaurants and bars with outdoor seating will be lovin' it, while it's not so pleasant in the temperature contrast zone where a variety of precipitation, heavy in some places, will continue.
UPDATE 1AM EST MONDAY
Here's a photo from TWC "Weather Warrior" Sonia Sansonetti near Versailles, Missouri which shows the scene following the major ice storm there Saturday night into Sunday. On the National Weather Service map of ice accumulations which follows, Versailles is in Morgan County.
To follow up on my tirade a week ago about hurricane season outlooks ...
The Weather Channel has adopted a "position" as stated below and condensed in the graphic which is airing today ... and moving forward, the policy will be that regardless of whose forecast it is, this set of caveats should routinely be communicated in tandem with broadcasting the outlooks.
>>>
Seasonal hurricane outlooks are inherently very uncertain and it is impossible to accurately predict critical details such as track, intensity, size and impact of any tropical cyclone months or weeks in advance. Therefore, regardless of any seasonal outlook, adequate preparation is imperative before and during each hurricane season.
>>>
Oprah has her "Favorite Things" show every year, which is a huge hit! So our Abrams and Bettes team thought it would be fun to have our version of "Favorite Things," but change it up a bit and have our "Green Favorite Things." There are lots of ideas so I asked the A & B team what their favorite green gifts are and have listed them below.
Mike: Dual-flush toilet. Press #1 button for #1 and it uses only 1.2 gallons per flush. Press #2 button for #2 and it uses 1.6gpf. Average household of 4 can save an estimated 13,000 gallons a year by switching to dual flush toilets. Installs just like a regular toilet.
Rashida: executive producer, keeps it simple! Cold Hard CashCarbon neutral, reusable. Best gift ever!
Rob: director, suggests that you replant your Christmas tree! This is a gift the whole family can share!
Stephanie: I like to buy presents that are useful and meaningful. By a simple switch of light bulbsyou can save on your electricity bill and help the environment at the same time! Just make sure you turn the light off when you leave the room. Every time the receiver of this gift turns on the lights he/she will think of you!
The other item I really like and use is the reusable grocery bag. I bought some from my local grocery store, but you can find them online too. Every plastic grocery bag takes up to 1000 years to degrade. Think about that the next time you are at the store. I have never bought anything from this site, but it seems to have a lot of good suggestions.
I would love to know which idea you like the best and let me know if you are considering being more environmentally friendly this holiday season. There are super easy ways to help the environment. I think one of the easiest things to do is wrap presents with newspaper!
Oh, how I hate when we scientists and educators define criteria, boxes, classes, classifications, regimes, definitions and ranges for things that in general confuse the public and force the public to know/understand the definition before they can decipher what we are trying to say.
All this jargon is fine within the scientific community that made it up and routinely uses it, but when it is shoved onto the general public it typically results in great confusion or, at the least, misinterpretation. Most of the time it is necessary as shorthand within a specific scientific discipline, but when removed from it and brought to the general public, especially through a mostly "language arts" trained media, the result is confusion and misuse. I will show you just a few of these to make my point.
Let me start with probably the most misunderstood pair of meteorological definitions that leads to confusion, namely tropical storm vs. subtropical storm. Let me say first, for you John Q. Public, what we call it doesn't matter; rather only what it can or will do to you matters.
I take all the following "definitions" directly from the source that routinely uses them, the National Hurricane Center. Just for clarification the symbol "kt" is shorthand for knots, nautical miles per hour. If you multiply knots by 1.15 you get miles per hour. Here are a few:
Hurricane:
A tropical cyclone in which the maximum sustained surface wind (using the U.S. 1-minute average) is 64 kt (74 mph or 119 km/hr) or more. The term hurricane is used for Northern Hemisphere tropical cyclones east of the International Dateline to the Greenwich Meridian. The term typhoon is used for Pacific tropical cyclones north of the Equator west of the International Dateline.
Tropical Storm:
A tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) ranges from 34 kt (39 mph or 63 km/hr) to 63 kt (73 mph or 118 km/hr).
Subtropical Storm:
A subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 34 kt (39 mph or 63 km/hr) or more.
Well, you might say, the last two sound the same to me, except for the upper wind limit added for "tropical storm." That's the point; relative to what they can do to you there often is no difference! The difference comes from the gory man-made "scientific" definition. And note that we have terms (marked with bold) within these definitions that require definition, namely:
Tropical Cyclone:
A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).
Subtropical Cyclone:
A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones.
Note that we need a few more man-made definitions to clarify the definitions we used to define the original definitions! Man, this gets more complicated for the media and the public by the minute, and hence leads to routine media mistakes, misdefining, misunderstanding and miscommunication, not to mention a total lack of knowledge by many who use the terms!
OK, now let's add a few more definitions that are routinely used to get you to take action and evacuation in vulnerable coastal areas, namely:
Tropical Storm Warning:
A warning that sustained winds within the range of 34 to 63 kt (39 to 73 mph or 63 to 118 km/hr) associated with a tropical cyclone are expected in a specified coastal area within 24 hours or less.
Hurricane Warning:
A warning that sustained winds 64 kt (74 mph or 119 km/hr) or higher associated with a hurricane are expected in a specified coastal area in 24 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continue, even though winds may be less than hurricane force.
Wow, more defined terms to define the warnings! And now we have a caveat for "Hurricane Warning" that we do not have for a "Tropical Storm Warning", namely, the fact that hurricane force winds are NOT necessary to keep a hurricane warning in place. You may ask why not for tropical storms as well? I have no answer for you, those other impacts also occur in a tropical storm.
So we have used definitions with definitions embedded within them to make definitions of actions the public is sometimes required to take! If you forget/forgot any or any part of a definition, then these warning definitions may not make sense or may not be fully understood.
Whatever you do, don't confuse a "warning" with a "watch"!
Tropical Storm Watch:
An announcement for specific coastal areas that tropical storm conditions are possible within 36 hours.
Hurricane Watch:
An announcement for specific coastal areas that hurricane conditions are possible within 36 hours.
And note that we now have two new terms that are not defined, "tropical storm conditions" and "hurricane conditions." Do they mean tropical storm and hurricane winds as defined above in the definition of "tropical storm" and "hurricane"? The answer is, not necessarily (based on my experience), but there is no definition for "conditions" provided by the National Hurricane Center!
If that is not confusing enough, application of these definitions to real life, real-time wind observations is often subjective due to lack of wind observations and observations with highly varying sampling times and anemometer (wind measuring device) heights, and the reality of the definitions used for the warnings!
For example, there are many times we do NOT ever see a 1-minute average wind of "tropical storm" or "hurricane" strength on the coast as the "tropical cyclone" makes "landfall."
Why not? One good reason is probably because I failed to include the definition for "U.S. 1-minute average wind" for you above; therefore, that portion of the total definition is a mystery! It means; "a 1-minute average wind at 10 meters (33 feet) for an open exposure free from buildings and trees"!
Yes, I know that means nothing for you, you and your homes are typically not 33 feet up in the air, away from all other homes and structures, nor are they void of trees, vegetation, power poles and lines and may not be on open exposure (there are hills, valleys, etc.). About the only place this is the case is at the beach 33 feet up in the air! What I mean is that most of you take that tropical storm warning to mean that you are going to get 1-minute average winds of 39 mph or higher. Fortunately, this doesn't happen very often over land! Much of the warning area never experiences sustained winds as high as those listed in the forecast advisory because you don't live on the beach with no obstructions in from of you (you may measure a brief gust that high, but not a 1-minute average of that strength) or perhaps there are/were no wind measurements to verify the wind exactly at 33 feet elevation!
I guess what I am trying to say with all of this is, I sympathize with you, John Q. Public! You should not have to deal with scientific terms and meteorological jargon, you should know what hits you when it hits you and you should clearly understand what a watch or a warning means when it is posted. Oh, but I am one of them, a scientist, and we all live in an imperfect world. I live in a world with scientific definitions, man-made confusion, and man-made media that can and sometimes does make communication of all this nomenclature to you unclear!
If I could change how we do all this, I'd change it in a minute. But no one person controls it, nor could he/she propose a perfect methodology. So instead of confusing you with all these definitions, I try hard to concentrate most on the upcoming impacts (winds/waves/water rise/rainfall) -- what is important to you, what is going to happen to your coast, to your house, what it could do to you. Watch The Weather Channel to get an idea of what your impacts are going to be. Because much of the media will be tossing around terms and listing warnings that may or may not mean anything to them or to you!
Well, the television show "Desperate Housewives" has had its tornado. In the context of other encounters with tornadoes in television shows, this one wasn't the worst. I remember one that aired while I was in graduate school that so infuriated me that I wrote a condemning letter to the television network. This one didn't bring me to that state, but maybe some of you wonder what my reactions were. What if the writers and producers had asked for my input? Here are my thoughts....
In general, this episode tried to convey proper safety precautions to the viewers. A few characters got caught up in their other problems and ran outside into the tornado. Bad idea! If you watched, one of the characters who was outside in the tornado (the mayor) got killed; more on that yet to come. But mostly they went to the basement or crawlspace or got into an interior bathroom or closet. Well done!
Lynnette and Mrs. McClusky got into a bathtub in a bathroom with an external wall and pulled a mattress overtop of them. Not ideal (should have been an interior room) but the bathtub is an option often mentioned. I should point out that bathtubs were a lot safer decades ago when they were made of metal and enamel. The plastic bathtubs today don't offer much protection!
One "precautionary" action set me off. Katherine Mayfair started putting tape across the windows as soon as the tornado watch was issued. There is no good reason to put tape over windows. The tape won't do any good, and the odds are very low of your house being hit. If your home does get hit by a tornado, the tornado winds or the flying debris will break the window - taped or not. We don't even advise taping windows for a hurricane. In that case, with a day or more of time to prepare and the odds much higher of being struck, putting plywood over the windows is a wise precaution.
A neighbor kid went door-to-door selling bottled water. Hardly necessary! People don't die of thirst waiting to be rescued from a tornado!
The time scale of the events wasn't totally realistic, but some parts were reasonable. Tornadoes were being reported several hours before the one that hit Wisteria Lane in Fairview. That isn't unusual in a tornado outbreak, as sometimes several lines of tornadic storms will move across an area; even across the same community. Injured people were being brought to the hospital, perhaps from the Mount Pleasant tornado, before Fairview got hit. That, too, can happen.
The initial tornado shown was almost rope-like, then a big wedge, whereas the one about to strike Wisteria Lane was a long, cylindrical "elephant trunk" or landspout-type tornado. This, too, is pretty realistic of a tornado outbreak. Some are big, others are small. We don't understand why, except that it probably involves very small differences on the storm scale, or in storm evolution, or in the near-storm environment - possibly due to interaction with nearby or previous storms.
As Lynette and Mrs. McClusky spotted the tornado, probably about a mile away, a charcoal grill fell from the sky. That's about the distance where a lot of debris can start falling from the sky, usually pieces of wood. Such shrapnel gets hurled upward, then outward by the tornado and can fall ahead of it. Eyewitnesses have told me that, and I've seen it in storm videos. Smaller items like papers can get carried even more than a hundred miles downwind from the tornado, having been shot up and then outward in strong winds aloft. I've even read of fish and frogs falling from the sky.
Winds started blowing a fence apart and a car fell from the sky just before the tornado hit. These types of events are usually within the tornado. Cars and other large objects do get hurled in tornadoes. While I haven't seen it happen in progress, I've personally looked at damage paths where large to huge objects got tossed. I walked the 75-100 yard path from a destroyed home to where the refrigerator and hot water tank came to rest. There were no bounce marks along the way! Of course, the whole house was also gone, broken to tiny pieces and hurled down the path along with these items.
Arguably the most frightening thing I've seen was in a sequence of slides taken by a resident of Wichita Falls, TX, during the tornado that hit there in 1979. He's trapped outside, crouching behind his pickup truck while the large tornado tears apart the townhouses across the street. Then all of a sudden this small object shows up in his frame, then it gets bigger, and in the final shot you can see that it's a whole room of a house that is being hurled toward him Miraculously, he survived!
The mayor and Carlos were outside fighting, with no difficulty standing, while fences were flying apart and a car dropped from the sky, but before the brunt of the tornado hit. The scene wasn't totally consistent. For them to be standing this easily, winds should have been less than about 40 mph. The breaking fences meant that winds should have been much higher, and parts of the nearby houses should have also been flying off. But the episode certainly showed that flying debris in a tornado can prove deadly - with one of those pieces of fence piercing the mayor. It probably had to be doing at least 75 mph to do that!
One of the characters got sucked out of a doorway and picked up into the tornado. Unfortunately, this can happen. People have been found (usually dead) considerable distances from where they were when the tornado struck. But Bree's house seemed to have been still holding its own at the time, and I think that it should have been flying apart at wind speeds fast enough to pick up a person right off the ground.
All of that took minutes to transpire on Wisteria Lane. Usually a tornado hits with a rather sudden frenzy, lasts 30 seconds or less at your location, and is gone. Well, this was fiction!
Here are a few other tidbits of actual tornado trivia. The ones from Pennsylvania in 1985 are from my own searches of newspaper stories from that outbreak, the worst in Pennsylvania history.
- A check blew 223 miles in a Kansas-Nebraska tornado on April 11, 1911
- A mattress from Worcester, Massachusetts, wound up 40 miles away in Boston Harbor on June 9, 1953
- A person was blown a mile away in Kickapoo, Kansas on May 1, 1930
- A person was blown 1307 feet in a tornado at Fordland, Missouri on March 12, 2006, and survived
- A sack of flour was blown 110 miles in a 1915 tornado at Great Bend, Kansas
- A refrigerator was blown a quarter mile in the Albion, Pennsylvania tornado of May 31, 1985
- An 800 pound ice chest was blown several miles in a tornado at Marshall, Missouri in 1880
- A 500 gallon propane tank, three-quarters full, was blown half a mile in Kansas in 1992
- A baby grand piano was blown 300 feet in the F5 Wheatland, Pennsylvania tornado of May 31, 1985
- A large farm gravity wagon was blown a mile in Corry, Pennsylvania on May 31, 1985
I think the year was 1974, it was winter in Hawaii and yes, I was in paradise attending the University of Hawaii, running on its track team and studying atmospheric science. Oh, and surfing every chance I got! Beautiful weather, northeast trade winds blowing at 10-15 mph and humidity that was amazingly low for an isolated tropical island location.
I was in paradise, at least until my first encounter that February with a "Kona Storm." I didn't even know what they called them let alone what they were; I had just arrived in Hawaii a few months earlier and had just changed majors from pre-med to atmospheric science (my parents loved that idea). I loved weather, and because of that they supported my change. I knew a lot about Southern California weather; I grew up there, but I didn't know much about Hawaiian weather -- until that Kona Storm came.
I went to sleep as the trade winds had weakened that evening and the sky everywhere was unusually cloudy for Hawaii. I woke the next morning to the sound of heavy rain; I didn't know it was even possible for it to rain that hard ("it never rains in Southern California")! It was coming down at a rate of one to two inches per hour out my window near the University of Hawaii, which, by the way, is in the Sugar Bowl this year and the only undefeated college football team in the nation. But I digress.
It was raining harder in the mountains just 2 miles north, cloud bases were barely off the ground and the mountains were shrouded in them. At first I thought, wow, a heavy morning shower, I see these all the time, just not this strong. But the rain continued and continued. I rode my bike to school in rapidly rising puddles and in rain so heavy I could barely see as the drops pelted my face. Well, it rained and it rained and two days later it was still raining. More than 2 feet of rain had fallen in many locations, flash flooding was occurring in the mountains, roads washed out, streams turned into rivers, and some houses flooded. Muddy red (from iron-rich soil) rain water raced down the streets of the university from the mountains still hidden in the clouds. It seemed to me that the land was in such pain from all the rain it was bleeding!
The track and football field was in the lower portion of the university; we called it the quarry back then, because it was an old rock quarry that had been transformed into a wonderful athletic facility, at least until those rains filled it with 3-5 feet of standing water! Four days later the rains finally stopped, the skies cleared, the trade winds came back and as if a miracle paradise had returned to Hawaii. I sure felt sorry for the tourists in Hawaii those four days.
OK, enough day dreaming. What's a Kona Storm, you ask? It is a cyclone that typically forms in the northern tropics or subtropics near or most typically just northwest of the Hawaiian Islands in the cool half of the year (most common from December to March). In other parts of the world they are just called subtropical cyclones or cut-off low pressure circulations.
They form when a deep trough of cold low pressure far north protrudes south near Hawaii and then cuts off a cold pocket of air at mid- and upper levels of the atmosphere (typically in the 12-20,000 feet levels of the atmosphere). This vigorous cut-off, mid-level cyclone then forms its own relatively weak surface low beneath it, or very slightly east of its center. This surface low just northwest of Hawaii causes winds to shift from the typical northeast (windward) direction to a southwest (leeward or Kona) direction. Hence, the Hawaiian name Kona Storm meaning a leeward wind storm.
Although winds can be 30-40 mph in extreme events most are dominated by winds in the 15-25 mph range with higher gusts. Higher mountain elevations more commonly see winds of 30-40 mph, sometimes higher. Kona Storms are extremely slow-moving and can persist near Hawaii for a number of days, and when vigorous can bring very persistent, heavy rains. Their tracks are slow, erratic, meandering and they can close in on Hawaii more than once in a single lifetime. Numerical models usually forecast the big picture aspects of a Kona Storm, but often fail to catch the small shifts in location that can be the difference between light rain and a day or two of tropical downpours. Models also often fail to forecast the longevity of strong events.
I hope you are not going on vacation to Hawaii from December 6-10 this year as a Kona Storm is beginning to develop just northwest of Hawaii, as if it knows where to set up; it's been there before! It is too early to tell whether this one will bring flooding rains to paradise, but it appears to me that it will be very wet, humid and not great vacation weather. One thing for sure you will get to experience a Kona Storm first hand, and in all its rage and glory those rains are beautiful, at least to a meteorologist like me.
For me it seems like the Kona Storm brings rains like cleansing hand from heaven, of everything that was not there when land first appeared about the ocean in that great volcanic event that became Hawaii.
