Hurricane PATRICIA

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TROPICAL STORM PATRICIA DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT FRI OCT 24 2003

DEEP CONVECTION ASSOCIATED WITH PATRICIA HAS INCREASED OVER THE PAST
SEVERAL HOURS...WITH TOPS OF COLDER THAN -80C NOW OBSCURING THE
LOW-LEVEL CENTER. HOWEVER...THE CONVECTION IS CURRENTLY POORLY
ORGANIZED. SATELLITE INTENSITY ESTIMATES ARE 35 KT FROM AFWA...AND
30 KT FROM TAFB AND SAB.  GIVEN THE INCREASE IN CONVECTION SINCE
THE PREVIOUS ADVISORY...PATRICIA WILL REMAIN A 35 KT TROPICAL
STORM.  WATER VAPOR IMAGERY AND SHEAR ANALYSES FROM CIMSS AT THE
UNIVERSITY OF WISCONSIN INDICATE THAT AN UPPER-LEVEL ANTICYCLONE IS
FORMING NEAR PATRICIA AND SIGNIFICANTLY DECREASING THE SHEAR...AND
THE CONVECTIVE FLARE-UP MAY BE TIED TO THAT.

THE INITIAL MOTION IS NOW 295/6.  WATER VAPOR IMAGERY SHOWS A
MID/UPPER-LEVEL LOW NEAR 24N124W WITH BROAD TROUGHING COVERING THE
AREA NORTH OF 18N EAST OF 140W TO NORTHWESTERN MEXICO.  LARGE-SCALE
MODELS INDICATE THAT THIS PATTERN WILL EVOLVE INTO AN EAST-WEST
TROUGH ALONG ROUGHLY 28N DURING THE FORECAST PERIOD.  IR IMAGERY
AND MODEL ANALYSES SHOW WEAK LOW-LEVEL RIDGING NORTH OF PATRICIA...
AND THIS SHOULD PERSIST THROUGH THE PERIOD.  ALL DYNAMICAL GUIDANCE
NOW CALLS FOR PATRICIA TO TURN NORTHWARD...AND ALL BUT THE UKMET
SHOW A NORTHEASTWARD TURN AFTER 48-72 HR.  THE UKMET FORECASTS
PATRICIA TO TURN WESTWARD INSTEAD.  FULL RECURVATURE STILL APPEARS
UNLIKELY...AS A COMBINATION OF COOLER SEA SURFACE TEMPERATURES AND
FORECAST STRONG SHEAR SHOULD CAUSE PATRICIA TO WEAKEN AS IT TRIES
TO RECURVE.  THUS...THE FORECAST TRACK WILL BE TO THE LEFT OF THE
BULK OF THE DYNAMICAL GUIDANCE.  THE NEW FORECAST IS SHIFTED TO THE
RIGHT OF THE PREVIOUS TRACK...CALLING FOR A TURN TOWARD THE
NORTH-NORTHWEST THROUGH 72 HR...THEN CALL FOR A SLOWER AND MORE
WESTWARD MOTION BEYOND 72 HR UNDER THE WEAK LOW-LEVEL RIDGE.
 
THE CURRENT DECREASE IN THE SHEAR SHOULD BE TEMPORARY.  INDEED...THE
GFS AND CANADIAN MODELS FORECAST IT TO INCREASE IN AS SOON AS 12
HR.  THE INTENSITY FORECAST WILL USE THE PREMISE THAT IT WILL TAKE
LONGER THAN THAT FOR CONDITIONS TO WORSEN...AND THUS CALL FOR
GRADUAL STRENGTHENING FOR 36 HR.  PATRICIA IS FORECAST TO CROSS
INTO SUB-26C SSTS BY 72 HR WHILE MOVING INTO INCREASING UPPER-LEVEL
WESTERLIES.  THIS COMBINATION SHOULD CAUSE STEADY WEAKENING.  IT IS
POSSIBLE THAT PATRICIA COULD DISSIPATE SOONER THAN CURRENTLY
FORECAST...ESPECIALLY IF NO STRENGTHENING OCCURS DURING THE FIRST
36 HR.
  
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/0900Z 14.0N 113.0W    35 KT
 12HR VT     24/1800Z 14.7N 113.7W    35 KT
 24HR VT     25/0600Z 15.9N 114.6W    40 KT
 36HR VT     25/1800Z 16.9N 115.1W    45 KT
 48HR VT     26/0600Z 17.9N 115.6W    45 KT
 72HR VT     27/0600Z 19.0N 116.5W    35 KT
 96HR VT     28/0600Z 20.0N 117.5W    30 KT
120HR VT     29/0600Z 20.5N 119.5W    25 KT...DISSIPATING
 
 
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