LARRY #7 - DISCUSSION

[AussieMark]

000
WTNT42 KNHC 030845
TCDAT2
TROPICAL STORM LARRY DISCUSSION NUMBER 7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT FRI OCT 03 2003

CONTINUITY IS USED IN THIS PACKAGE SINCE THE NEXT RECONNAISSANCE
PLANE IS NOT EXPECTED TO BE IN THE AREA UNTIL 1200 UTC. SATELLITE
IMAGES DO NOT SHOW MUCH OF AN ORGANIZED CLOUD PATTERN ASSOCIATED
WITH LARRY. BUT BOTH MICROWAVE DATA AND A RADAR LOOP FROM ALVARADO
MEXICO SHOW A DISTINCT LOW-LEVEL CENTER. INITIAL INTENSITY IS THEN
KEPT AT 50 KNOTS UNTIL THE AIR FORCE PLANE MEASURES THE WINDS LATER
THIS MORNING. I AM TEMPTED TO WEAKEN THE CYCLONE IN THE OFFICIAL
FORECAST DUE TO THE CURRENT ORGANIZATION AND UNFAVORABLE
UPPER-LEVEL WINDS BUT THE INTENSITY GUIDANCE EITHER MAINTAINS THE
CURRENT INTENSITY OR STRENGTHENS THE CYCLONE.

LARRY CONTINUES TO BE TRAPPED WITH LITTLE MOTION IN THE BAY OF
CAMPECHE. RISING PRESSURES TO THE NORTH WILL PROBABLY FORCE LARRY
TO DRIFT SOUTHWARD FOR THE NEXT FEW DAYS AS INDICATED IN THE
OFFICIAL FORECAST.

GLOBAL MODELS SHOW BASICALLY LITTLE MOTION. IN FACT...THE GFS KEEPS
A RATHER STRONG CYCLONE IN THE SOUTHERN GULF OF MEXICO DURING ITS
ENTIRE 384-HOUR RUN...YES...384-HOUR RUN. BOTH THE UK MODEL AND
THE NOGAPS WEAKEN THE CYCLONE OVER LAND BUT MAINTAIN A LARGE AREA
OF LOW PRESSURE FOR SEVERAL DAYS BUT THE CANADIAN MODEL KEEPS A
CYCLONE IN THE GULF OF MEXICO. REGARDLESS OF THE MODEL
SOLUTION...IT APPEARS THAT A BROAD AREA OF LOW PRESSURE WILL
PERSIST EITHER IN THE GULF OF MEXICO OR OVER CENTRAL AMERICA FOR
SEVERAL DAYS. THIS PATTERN WOULD TYPICALLY BRING MOIST AIR FROM THE
PACIFIC RESULTING IN HEAVY RAINS AND MUD SLIDES.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL 03/0900Z 20.4N 94.1W 50 KT
12HR VT 03/1800Z 20.4N 94.1W 50 KT
24HR VT 04/0600Z 20.0N 94.0W 55 KT
36HR VT 04/1800Z 19.5N 94.0W 60 KT
48HR VT 05/0600Z 19.5N 94.0W 60 KT
72HR VT 06/0600Z 19.0N 94.0W 55 KT
96HR VT 07/0600Z 18.5N 94.0W 35 KT
120HR VT 08/0600Z 18.0N 94.5W 25 KT...INLAND