Tropical Storm LARRY
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TROPICAL STORM LARRY DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT FRI OCT 03 2003
THE AIR FORCE RESERVE HURRICANE HUNTER REPORTED A CENTRAL PRESSURE
OF 995 MB AT 17Z...ALONG WITH FLIGHT-LEVEL WINDS THAT WOULD SUPPORT
ABOUT 45 KT SURFACE WINDS. HOWEVER...LARRY HAS INCREASED IN
ORGANIZATION IN BOTH SATELLITE AND RADAR IMAGERY...AND BASED ON
THESE MIXED SIGNALS THE INITIAL INTENSITY WILL REMAIN 50 KT. IT
SHOULD BE NOTED THAT EVEN THOUGH THE TOPS ARE WARMING IN THE
CURRENT CONVECTIVE BURST...THE RADAR PRESENTATION FROM ALVARADO
MEXICO IS BECOMING MORE IMPRESSIVE.
THE INITIAL MOTION REMAINS A VERY UNCERTAIN 235/2. THERE IS NO
CHANGE IN THE FORECAST PHILOSOPHY...AS LARRY REMAINS TRAPPED IN AN
AREA OF WEAK STEERING CURRENTS AND IS LIKELY TO STAY THAT WAY FOR
THE NEXT 3-5 DAYS. MOST DYNAMICAL GUIDANCE CALLS FOR A SLOW MOTION
BETWEEN SOUTHEAST AND SOUTHWEST DURING THE FORECAST PERIOD...SO THE
OFFICIAL FORECAST WILL UPDATE THE SLOW SOUTHWARD DRIFT FROM THE
PREVIOUS PACKAGE. THIS MOTION SHOULD BE RATHER UNSTEADY...WITH
JUMPS IN THE POSITION OF THE CENTER. THE MID-LEVEL VORTICITY
CENTER EARLIER SEEN NORTHEAST OF LARRY SEEMS TO BE MOVING
NORTHEASTWARD AND WILL NOT LIKELY HAVE MUCH EFFECT ON THE STORM
LARRY IS THE NORTH OF AN EAST-WEST ORIENTED UPPER-LEVEL RIDGE...AND
THIS IS EXPOSING THE STORM TO LIGHT/MODERATE WESTERLY SHEAR.
LARGE-SCALE MODELS SUGGEST THAT THE SHEAR SHOULD DECREASE LATER IN
THE FORECAST PERIOD...WHICH WOULD ALLOW STRENGTHENING IF PROXIMITY
TO LAND DOES NOT HINDER IT. A WILD CARD IN THE INTENSITY FORECAST
IS THAT THE SLOW MOTION IS GIVING LARRY TIME TO UPWELL COLD WATER
UNDERNEATH IT. SHOULD LARRY NOT MOVE...IT WILL EVENTUALLY UPWELL
COLD ENOUGH WATER TO LITERALLY PUT THE CHILL ON INTENSIFICATION.
HOWEVER...IT IS UNCERTAIN HOW LONG THAT MIGHT TAKE.
INITIAL AND FORECAST WIND RADII HAVE BEEN REVISED BASED ON THE
AIRCRAFT DATA AND THE FORECAST PROXIMITY TO LAND.
FORECASTER BEVEN
FORECAST POSITIONS AND MAX WINDS
INITIAL 03/2100Z 19.9N 94.7W 50 KT
12HR VT 04/0600Z 19.6N 94.7W 50 KT
24HR VT 04/1800Z 19.4N 94.7W 55 KT
36HR VT 05/0600Z 19.2N 94.7W 55 KT
48HR VT 05/1800Z 18.9N 94.7W 60 KT
72HR VT 06/1800Z 18.4N 94.8W 60 KT...INLAND
96HR VT 07/1800Z 18.0N 95.0W 30 KT...INLAND
120HR VT 08/1800Z 17.5N 95.5W 20 KT...INLAND DISSIPATING
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