Extreme heat repeat – July 4th was hot as a firecracker in the Southwest – Death Valley was the hot spot of the nation at 126°F, with a handful of other Southwest cities topping 115 F (Needles, Imperial and Blythe, Calif., and Phoenix, Bullhead City, Gila Bend, Casa Grande and Roosevelt, Ariz.). Look for similar heat to overspread the West today, with excessive heat warnings in place for inland sections of Southern California, southern Nevada and western Arizona. Heat advisories are in effect for western Arizona (including Reno) as well as parts of southern Washington and northern Oregon.

At time of writing (6 a.m. ET), the temperatures in both Las Vegas and Phoenix are sitting at a sultry 92°F. With such a warm morning start, both cities should easily top 110°F again today.

Of course, dealing with extreme heat comes with living in a desert environment. Some of the deadliest heat waves have occurred in cities farther to the north (Chicago, Philadelphia), where prolonged, excessive heat has caught residents unawares and unprepared. (Graphic reprinted from USA TODAY newspaper)

In conversation with Buzz Bernard, senior forecaster at The Weather Channel, this morning, he mentioned that, on Monday afternoon, an hourly observation at Las Vegas showed an air temperature of 110°F and a dew point of -7°F! Doing the math yields a dew-point depression (the difference between air temperature and dew point) of 117°F and a relative humidity around 1%. Now that's what I call a dry heat!

That astounding value for relative humidity also brought to mind a past "Ask the Experts" reader question -- can relative humidity ever reach zero percent?

Of course, in such conditions, sweating is the order of the day. In fact, the motto for holiday revelers in the West should be, "Go Fourth and Perspire!" Triple-digit temperatures will be widespread this afternoon, with excessive heat warnings in effect for western Arizona, southern Nevada and eastern parts of Southern California (this includes inland parts of the San Diego metro area). Heat advisories are in effect for southern Arizona (including Tucson), western Nevada (including Reno) and even parts of the Columbia River Valley in northern Oregon and southern Washington. Heat advisories remain in place for most locations through Friday.

(Kaan Beyaz, left, Alara Dinc, center, and Baris Beydaz, all from Turkey, cool off in the mist on the Strip in Las Vegas, Tuesday, July 3 , 2007. Photo by Jae C. Hong, AP)

Lone Star soaking – While parts of Missouri, Kansas, Oklahoma and Arkansas continue to grapple with rain that has already fallen and is still finding its way into streams and rivers, another dry day for most of these areas will allow for some of the flooding to subside. Not so for southern Texas as well as the Texas Gulf Coast and southwestern Louisiana. Rain will be heavy at times in these locations today. Concern for additional flooding this week will be in southern Texas into the Rio Grande Valley – this is where most of the rainfall will be focused in the next few days.

As temperatures soar to near record levels in the Southwest this week, a new study reports that U.S. death rates in the summer are expected to rise because of global warming. The study notes that more Americans should die because of hot summer weather than would be saved by the milder winters associated with global warming.

Researchers found that during two-day cold snaps there was a 1.59 percent increase in deaths because of the extreme cold. However, during similar periods of extremely hot weather, death rates went up by 5.74 percent.

The Harvard study was published online in the journal Occupational and Environment Medicine. Researchers analyzed city-specific weather data related to the deaths of more than 6.5 million people in 50 U.S. cities between 1989 and 2000.

The authors, Mercedes Medina-Ramón and Joel Schwartz of the Harvard School of Public Health, report that "our findings suggest that decreases in cold weather as a result of global warming are unlikely to result in decreases in cold-related mortality in the U.S. Heat-related mortality, in contrast, may increase, particularly if global warming is associated with increased variance of summer temperature."

While all 50 U.S. cities showed similar rises in deaths when temperatures plummeted, more deaths were seen during extreme temperature rises in cities with milder summers, less air conditioning and higher population density.

Blistering heat will be the rule across the Desert Southwest over the next few days. According to the National Weather Service, daytime temperatures through Thursday will be 6 to 12 degrees above normal for early July, with many locations near or breaking daily record highs.

Excessive heat warnings and heat advisories have been posted throughout the region. An excessive heat warning means that a prolonged period of dangerously hot weather will occur.

Readers poked fun at the article I wrote a couple of weeks ago, part of which noted that the Southwest was forecast to be unusually hot this summer. But the forecast has verified, at least for now. While high temperatures in the 100s are common there, temperatures at or above 120 degrees are far above the region's average highs.

(Graphic reprinted from USA TODAY newspaper)

I'm not the biggest Grateful Dead fan, but I found myself humming the song, Box of Rain, after receiving a press release about water packaged in boxes rather than those ubiquitous plastic bottles. The product resonates with me, not because I buy a lot of bottled water, but because I recently read about how many water bottles get tossed each year. Those bottles, of course, wind up in landfills and new ones have to be produced (using petroleum or natural gas) to meet the demands of a thirsty nation.

The boxed water, Aqua2Go, looks much like a drink box and 74% of the Tetra Brik Aseptic package is made from renewable resources. The box is recyclable and, because it is largely paper, is more biodegradable than most plastic bottles in the event that it does wind up in the landfill.

I think it's a great idea and I'm not alone -- Ellen Degeneres pitched an idea for a Water2Go commercial on her show!

(The packaging of the Aqua2Go purfied water box is 74% paper, 20% plastic and 6% aluminum. Photo by Carlton Mickle)

Need to find out the temperature, and don't have a thermometer handy? Charlie Wilson of Internet Partnership Radio reminded me today of how you can tell the temperature at night in the summer by listening to cricket chirps:

Count the number of cricket chirps in 15 seconds, and add 40. That's the temperature at ground level in degrees Fahrenheit. (The temperature will be slightly warmer around your head.) The chirping of the crickets seems to be influenced by the air temperature -- the hotter it gets, the more they seem to want to "talk" about it. (Courtesy of Stu Ostro of the Weather Channel.)

This is known as Dolbear's Law (named after American physicist and inventor Amos Dolbear) and was featured in an entertaining article in the Vineyard Gazette in 2005.

(Photo by Darin Oswald, The Idaho Statesman)

I must admit that I don't spend much time on the water and certainly have not been out boating during a thunderstorm. However, this article from the University of Florida's William Becker is packed with boating safety tips, as well as some guidelines for assessing the lightning protection systems in a new or used boat.

Got any inclement-weather boating tips or stories to share? Feel free to leave your comment by clicking below. (Graphic reprinted from USA TODAY newspaper)

Rainy days and Mondays – There seems to be no end to the showers and storms plaguing the southern Plains and more rainfall is expected today from South Texas through eastern Oklahoma and western Arkansas. While rain is expected to continue for much the same area tomorrow, parts of Missouri and Kansas should stay dry the next few days, allowing streams and rivers to return to the confines of their banks. There will be even be some relief for Texas on Wednesday, as the upper-level low drifts into northern Mexico, taking the bulk of the rainfall into the Rio Grande Valley.

This week's weather photo gallery is packed with poultry -- there is one photo of a swan swimming down the backstretch of a racetrack as well as the photo at left of ducks on the banks of Walden Pond. I'm not sure if Henry David Thoreau ever did any sunbathing after he "went to the woods . . . to live deliberately," but I'm pretty sure that he was not as striking as the gal in the background of this photo.

(Ducks walk around near shore where bathers enjoy the sun at Walden Pond in Concord, Mass., Thursday, June 28, 2007. Photo by Elise Amendola, AP)

"Spanning the globe, to bring you the constant variety of weather..."

I was going to write a post about this cool NASA photo of noctilucent clouds (below), when I came across this photo of a car flooded out in Texas (above)... While the cloud photo is pretty neat, this photo of the flooded car just touched me for its sheer, simple stupidity (see my previous post for why you shouldn't try this at home.)

The caption that accompanied the photo was also rather droll: "A motorist stalls amid floodwaters..." Um, really?

As for the noctilucent clouds, this was the first satellite photo taken this summer of the mysterious shiny polar clouds that form 50 miles above Earth’s surface. The photo was taken aboard NASA's AIM satellite, which is the first satellite mission dedicated to the study of these unusual clouds.

And another week ends here in the USA TODAY weather office.

"... the thrill of victory, and the agony of defeat..."

(Top photo: By Ron Jenkins, Fort Worth Star Telegram/AP;  Bottom photo: NASA)

Hello, is anybody listening out there? Despite the endless warnings from the media and the National Weather Service, with their "Turn around, don't drown" campaign, cars -- and the people who drive them -- continue to end up in the wrong places during floods. It may be hard for drivers to believe, but it only takes two feet of moving water to float most cars.

Although the "bull's-eye" for rainfall might move north into Oklahoma over the next few days, enough rain is forecast to fall in saturated central Texas for flood worries to continue well into next week.

(Graphic reprinted from USA TODAY newspaper)

Reading about Congress' grilling of former EPA chief Christie Whitman reminded me of the days following 9/11, and how the gorgeous September weather that week was in stark contrast to the hellish, surrealistic images from the World Trade Center and the Pentagon.

With the cold front that had just moved off the East Coast on Sept. 11, 2001, the winds in New York City were out of the north and northwest, which blew the plumes of smoke from Ground Zero to the south and southeast. By the next day, as winds shifted more to the north and northeast, the smoke blew to the southwest into New Jersey, as seen on this satellite image (above).

When we check out our weather forecast each day, wind direction likely isn't one of the conditions we look at -- we want to know the predicted high temperature and whether or not it's going to rain. But with the ongoing threats of dirty bombs and other nightmarish terrorist weapons, being aware of which way the wind is blowing -- and having an escape route in the opposite direction -- could indeed make the difference between life and death.

(AP/USGS satellite photo from Sept. 12, 2001)

Following record-tying heat in Boston on Wednesday, there is one more day of warm, muggy weather on tap for the Northeast and Mid-Atlantic. Thunderstorms will form along and ahead of a cold front that will sweep through the Northeast today and tonight, bringing cooler and drier weather for the weekend.

Abundant moisture in the atmosphere may lead to torrential rainfall and urban and flash flooding. There isn't much shear in the atmosphere -- winds are mainly from the west with increasing altitude -- so tornadoes are not a major threat. Likewise, with the cold air relatively high in the atmosphere, hail that forms is likely to largely melt on its way down. Downburst winds appear to be the biggest threat with this system, not only in producing wind damage, but also giving rise to other thunderstorms in multicell clusters. (Graphic reprinted from USA TODAY newspaper)

As we deal with floods in Texas and wildfires in California today, at least we don't have much severe weather to worry about, which is why this NASA satellite image caught my eye -- a cool shot of a tornado's damage path in Wisconsin. The tornado, one of a series of twisters that caused property damage but no injuries, hit northern Wisconsin on June 7. This image was taken on June 15.

According to the NASA press release, this natural-color image taken from Landsat 7 shows the area around the Wolf River and Bear Paw Resort just north of the Menominee Indian Reservation. The diagonal slash across the landscape from one of the tornadoes is quite dramatic in this full-resolution image.... the wide, bare swath of destruction from the tornado is very evident here, where trees were torn down by winds, leaves stripped from their branches or where agricultural fields outside the Reservation were flattened.

(Image from NASA's Earth Observatory)

The big stories dominating the weather wires this morning are the continuing fire threat in the vicinity of Lake Tahoe and the torrential rainfall across parts of the Southern Plains.

Firefighters had made some progress in containing the Angora fire near Lake Tahoe on Tuesday, but the fire managed to jump a line as winds increased Tuesday evening. More wind gusts up to 35 mph will make the battle difficult and dangerous today and the situation will not be getting any better on Thursday. Winds at the ridgelines may gust to 50 mph on Thursday, so the likelihood of containing the fire appears to be decreasing by the hour. Check out more fire coverage by the Reno Gazette-Jounal.

In the Texas Hill Country northwest of Austin, the rainfall has been unbelievably torrential during the overnight and morning hours. Around 19 inches of rain has fallen in parts of Burnet and Blanco Counties. The South Fork of the San Gabriel River is running at least 21 feet above flood stage and the rain is still falling. Additional coverage can be found on the News 8 Austin website.

I personally can't get over some of the rain in Texas -- 19 inches is more than is produced by many tropical systems. Apparently, the rain developed due to the merger overnight of an MCS (mesoscale convective system) that moved out of New Mexico and the North Texas panhandle and a slow-moving mid-level low that is sitting over northcentral Texas.

Have you been affected either by the fires or the flooding? Share your eyewitness account by clicking the comment button below.

Turns out that the death toll from lightning-related incidents climbed to 20 shortly after this graphic went to press. A 57 year-old woman was struck and killed yesterday afternoon while doing yard work outside her home in  Panama City, Fla.

To learn about other lightning-related injuries and fatalities both domestic and international, check out the lightning-strike database on the StruckByLightning.org website. (Graphic reprinted from USA TODAY newspaper)

July is usually the deadliest month when it comes to lightning fatalities, which is why NOAA chooses the last week in June as Lightning Safety Awareness Week.

Bob Dylan, perhaps unwittingly, included lightning safety tips when he penned Chimes of Freedom from his 1964 album, Another Side of Bob Dylan. In the opening stanza he sings, "We ducked inside the doorway, thunder crashing." Sounds a bit like NOAA's lightning safety slogan, "When thunder roars, go indoors!" From his safe vantage point, Dylan goes on to poetically describe the storm -- the "wild ripping hail," the "blowin' wind," and the "majestic bells of bolts" that rang like chimes of freedom.

An article, "Tonight as I Stand Inside the Rain--Bob Dylan and Weather Imagery," was published in the April 2005 issue of the Bulletin of the American Meteorological Society.  Alan Robock of Rutgers University writes about the influence of weather on Dylan's songwriting, detailing Dylan's poetic descriptions of weather and how these descriptions are used to evoke emotions in the listener.

So do you have a favorite Dylan tune with a weather-related title or lyric? Post your comment below.

(The album cover of Another Side of Bob Dylan. Photo courtesy Sony Music)

As Europe endures two deadly weather extremes -- high heat in southeast Europe and record flooding in England -- the British are preparing for more disasters brought on by global warming, which USA TODAY reported in today's paper:

Britain's armed forces chief said military planners are preparing for conflicts and humanitarian disasters brought on by global warming. Jock Stirrup, chief of the defense staff, said the security threat was far more immediate than is apparent from scientists' predictions of average temperature rises by the end of the century. The unpredictability of the effects of global warming on rainfall patterns and storms means flash points could advance by years without warning, Stirrup told a think tank in London. "We could already start to see serious physical consequences by 2040 — and that is if things get no worse," he said.