Hurricane PATRICIA

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TROPICAL STORM PATRICIA DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT THU OCT 23 2003

PATRICIA REMAINS SHEARED THIS MORNING WITH THE LOW LEVEL-CENTER
EXPOSED TO THE WEST OF THE MAIN CONVECTIVE CLUSTER....WHICH HAS
DECREASED IN COVERAGE AND INTENSITY OVER THE PAST FEW HOURS.  NEW
BURSTS OF CONVECTION HAVE BEEN DEVELOPING SOUTH AND SOUTHWEST OF
THE CENTER.   SATELLITE INTENSITY ESTIMATES ARE 55 KT FROM SAB AND
AFWA...AND 45 KT FROM TAFB.  THE INITIAL INTENSITY REMAINS 50 KT.

THE INITIAL MOTION IS NOW 290/9.  WATER VAPOR IMAGERY SHOWS AND
UPPER-LEVEL LOW NEAR 22N128W WITH A TROUGH EXTENDING TO 14N116W. 
IR SATELLITE IMAGERY AND LARGE-SCALE MODEL ANALYSES INDICATE THAT
PATRICIA IS SOUTH OF A WEAK LOW/MID-LEVEL RIDGE.  THE COMBINATION
OF EASTERLY LOW-LEVEL FLOW AND WESTERLY UPPER-LEVEL FLOW SUGGESTS
SEVERAL POSSIBLE FORECAST SCENARIOS...WHICH IS REFLECTED IN THE
SPREAD OF THE MODEL GUIDANCE.  THE GFDL CALLS FOR PATRICIA TO
RECURVE BACK TOWARD THE MEXICAN COAST AS A HURRICANE...AND THIS IS
SUPPORTED BY LBAR AND BAMD.  THE GFS CALLS FOR A WEAKER SYSTEM TO
CONTINUE WEST-NORTHWESTWARD...AND IT IS SUPPORTED BY THE BAMM AND
BAMS.  THE NOGAPS AND THE UKMET CALLS FOR A TURN TOWARD THE
NORTH-NORTHWEST...FOLLWED BY A TURN TOWARD THE WEST AFTER 72 HR. 
SINCE PATRICIA IS CURRENTLY POORLY-ORGANIZED AND VERTICAL SHEAR
SHOULD NOT ALLOW MUCH DEVELOPMENT...THE FORECAST TRACK IS A BLEND
BETWEEN THE GFS...NOGAPS...AND UKMET SOLUTIONS.  IT CALLS FOR A
BEND TO THE NORTHWEST IN 12-24 HR...FOLLOWED BY A GRADUAL TURN TO
THE WEST-NORTHWEST AFTER 72 HR.

LARGE-SCALE MODELS CONTINUE TO FORECAST THAT PATRICIA WILL BE
AFFECTED BY WESTERLY SHEAR THROUGH THE FORECAST PERIOD.  THUS...THE
INTENSITY FORECAST WILL CALL FOR NO CHANGE IN STRENGTH THROUGH 48
HR.  THE MODELS SUGGEST THE POSSIBILITY THAT THE SHEAR COULD
TEMPORARILY DECREASE IN ABOUT 24 HR...BUT THE CONFIDENCE IN THIS IS
LOW AND IT WILL NOT BE REFLECTED IN THE FORECAST.  AFTER 48 HR...A
WEAKENING TREND SHOULD BEGIN AS THE CYCLONE ENCOUNTERS COOLER SEA
SURFACE TEMPERATURES.

FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/0900Z 13.1N 110.0W    50 KT
 12HR VT     23/1800Z 13.8N 111.0W    50 KT
 24HR VT     24/0600Z 14.6N 111.9W    50 KT
 36HR VT     24/1800Z 15.6N 112.9W    50 KT
 48HR VT     25/0600Z 16.7N 113.9W    50 KT
 72HR VT     26/0600Z 18.5N 115.5W    45 KT
 96HR VT     27/0600Z 19.5N 118.0W    40 KT
120HR VT     28/0600Z 20.0N 120.5W    35 KT
 
 
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