Tropical Storm ANDRES

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TROPICAL STORM ANDRES DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT TUE MAY 20 2003
 
INFRARED IMAGES SHOW A PERSISTENT AREA OF DEEP CONVECTION WITH SOME
SYMMETRY AND BANDING...RESULTING IN DVORAK INTENSITY ESTIMATES OF
35 KT FROM TAFB AND SAB.  THE DEPRESSION IS UPGRADED TO TROPICAL
STORM ANDRES ON THIS BASIS.  0936Z TRMM PASS SUGGESTS THE LOW LEVEL
CLOUD CENTER IS DISPLACED NORTHWEST OF THE CENTER OF THE DEEP
CONVECTION.  FIRST VISIBLE IMAGE DOES NOT HELP MUCH IN LOCATING LOW
LEVEL CENTER. A VERY RECENT QUIKSCAT PASS SHOWS AN EAST/WEST
ELONGATED CENTER TO THE NORTHWEST OF THE DEEP CONVECTION ALONG WITH
AN UNCONTAMINATED 40 KT SURFACE WIND AND A COUPLE OF 60-65 KT
FLAGGED RAIN-CONTAMINATED SURFACE WINDS.
 
THE INITIAL MOTION ESTIMATE IS 270/09.  GLOBAL MODEL GUIDANCE SHOWS
A MID-LEVEL RIDGE PERSISTING TO THE NORTH OF THE STORM FOR SEVERAL
DAYS AND TRACK GUIDANCE VARIES BETWEEN DUE WESTWARD AND
WEST-NORTHWESTWARD.  THE FORWARD MOTION FROM THE GFDL MODEL IS
RATHER SLOW WHILE THE GFS MODEL IS CONSIDERABLY FASTER.  THE
OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND FOLLOWS A
CONSENSUS OF THE AVAILABLE GLOBAL MODELS.
 
THE GFDL AGGRESSIVELY BRINGS THE WIND SPEED TO 78 KT IN 60 HOURS AND
THE SHIPS BRINGS IT TO 60 KT...OVER WARM SSTS AND WEAK VERTICAL
SHEAR.  THE GFS...NOGAPS...AND UKMET MODELS FORECAST LITTLE CHANGE
IN INTENSITY FOR 120 HOURS.  THE OFFICIAL WIND SPEED FORECAST IS TO
55 KT BY 36 HOURS FOLLOWING THE PREVIOUS ADVISORY AND SHIPS.
 
FORECASTER LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/1500Z  9.9N 105.7W    35 KT
 12HR VT     21/0000Z 10.0N 107.2W    40 KT
 24HR VT     21/1200Z 10.5N 109.5W    50 KT
 36HR VT     22/0000Z 11.2N 111.8W    55 KT
 48HR VT     22/1200Z 11.8N 114.5W    55 KT
 72HR VT     23/1200Z 13.0N 119.5W    55 KT
 96HR VT     24/1200Z 14.0N 123.0W    45 KT
120HR VT     25/1200Z 15.0N 127.0W    35 KT
 
 
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