ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE LESTER DISCUSSION NUMBER 20 NATIONAL WEATHER SERVICE MIAMI FL 2 PM PDT MON OCT 19 1998 LESTER CONTINUES TO UNDERGO EAST/NORTHEASTERLY VERTICAL WIND SHEAR ...ASSOCIATED WITH THE MID-TO UPPER LEVEL LOW CURRENTLY OVER NORTHERN GUATEMALA....WHICH IS INHIBITING THE OUTFLOW NORTH AND EAST OF THE CENTER. INDEED...PART OF THE LOW-LEVEL CIRCULATION IS EXPOSED ON THE EAST SIDE OF THE CYCLONE. THE INITIAL INTENSITY IS REDUCED TO 80 KNOTS...IN GOOD AGREEMENT WITH DVORAK ESTIMATES. THE GLOBAL MODELS ARE FORECASTING THE MID-TO UPPER LEVEL LOW TO MOVE WESTWARD INTO SOUTH CENTRAL MEXICO AND WEAKEN BY 48 HOURS. THE STATISTICAL HURRICANE INTENSITY PREDICTION SCHEME...SHIPS...ACTUALLY STRENGTHENS LESTER SLIGHTLY...TO 90 KNOTS BY 24 HOURS. DUE TO THE UNCERTAINTY SURROUNDING THE FUTURE UPPER ENVIRONMENT...THE INTENSITY WILL BE HELD AT 80 KNOTS UNTIL A SOLID TREND...UP OR DOWN...IS IDENTIFIED. AS SUSPECTED EARLIER...AND CONFIRMED BY SATELLITE FIXES THROUGH THE DAY...THE CENTER OF LESTER IS SLIGHTLY NORTH OF THE PREVIOUS ESTIMATES. THE INITIAL MOTION IS NOW 280/10 KNOTS. THE SYNOPTIC REASONING BEHIND THE FORECAST TRACK REMAIN UNCHANGED FROM THE PREVIOUS PACKAGE AS THE MID-TROPOSPHERIC RIDGE NORTH OF THE TROPICAL CYCLONE SHOULD KEEP IT ON A GENERAL WESTWARD COURSE FOR THE NEXT DAY OR SO WITH A MORE WEST-NORTHWEST HEADING THEREAFTER AS LESTER NEARS THE WESTERN PERIPHERY OF THE RIDGE. THE OFFICIAL TRACK FORECAST IS SLIGHTLY TO THE RIGHT OF THE PREVIOUS PACKAGE MOSTLY DUE TO THE POSITION ADJUSTMENT. THE GOVERNMENT OF MEXICO HAS DISCONTINUED THE HURRICANE WATCH FOR THE SOUTHERN COAST OF MEXICO. THUS...THE LAST PUBLIC ADVISORY WILL BE ISSUED WITH THIS PACKAGE UNLESS LESTER THREATENS LAND AGAIN. GUINEY FORECAST POSITIONS AND MAX WINDS INITIAL 19/2100Z 14.7N 102.9W 80 KTS 12HR VT 20/0600Z 14.9N 104.5W 80 KTS 24HR VT 20/1800Z 15.4N 106.5W 80 KTS 36HR VT 21/0600Z 16.0N 108.5W 80 KTS 48HR VT 21/1800Z 16.5N 110.0W 80 KTS 72HR VT 22/1800Z 17.5N 112.5W 80 KTS NNNN