Tropical Storm SONIA

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TROPICAL STORM SONIA DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182013
700 PM PST SUN NOV 03 2013
 
MUCH OF THE DEEP CONVECTION ASSOCIATED WITH SONIA IS BEING DISPLACED
TO THE NORTHEAST OF THE ESTIMATED LOW-LEVEL CENTER LOCATION DUE TO
INCREASING SOUTHWESTERLY SHEAR...AND THE OVERALL CLOUD PATTERN IS
BECOMING LESS ORGANIZED.  THE CURRENT INTENSITY ESTIMATE IS REDUCED
TO 35 KT IN AGREEMENT WITH DVORAK T-NUMBERS FROM BOTH SAB AND TAFB. 
SONIA COULD WEAKEN TO A DEPRESSION JUST BEFORE MAKING LANDFALL...
AND RAPID WEAKENING WILL ENSUE AFTER THE CYCLONE MOVES INLAND DUE
TO MOUNTAINOUS TERRAIN AND PROHIBITIVELY HIGH SHEAR.  THE OFFICIAL
FORECAST SHOWS A 24-HOUR FORECAST POINT FOR A REMNANT LOW OVER
MEXICO...ALTHOUGH IT IS DOUBTFUL THAT THE SYSTEM WILL BE ABLE TO
ACTUALLY MAINTAIN ITS IDENTITY FOR THAT LONG.

THE CENTER LOCATION IS RATHER UNCERTAIN...BUT IT APPEARS THAT THE
FORWARD SPEED HAS INCREASED AND THE MOTION ESTIMATE IS NOW 030/15. 
THIS MOTION SHOULD BE MORE OR LESS MAINTAINED FOR THE NEXT 12 TO 24
HOURS WHILE SONIA IS EMBEDDED IN THE FLOW AHEAD OF A BROAD
MID-TROPOSPHERIC TROUGH.  THE OFFICIAL FORECAST IS A LITTLE FASTER
THAN THE PREVIOUS ONE DUE TO THE FASTER INITIAL MOTION.  THIS IS
VERY CLOSE TO THE LATEST MULTI-MODEL CONSENSUS.
 
THE PRIMARY THREAT FROM SONIA CONTINUES TO BE LOCALLY HEAVY RAINFALL
THAT IS EXPECTED TO AFFECT PORTIONS OF WESTERN MAINLAND MEXICO OVER
THE NEXT DAY OR SO.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/0300Z 23.2N 108.1W   35 KT  40 MPH
 12H  04/1200Z 25.0N 107.0W   30 KT  35 MPH...INLAND
 24H  05/0000Z 27.0N 104.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 36H  05/1200Z...DISSIPATED
 
$$
FORECASTER PASCH
 
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