Tropical Storm BORIS

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TROPICAL STORM BORIS DISCUSSION NUMBER  25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP022008
800 PM PDT WED JUL 02 2008
 
BORIS IS STUBBORNLY CONTINUING TO DISPLAY RELATIVELY SYMMETRIC DEEP
CONVECTION DESPITE MOVING OVER COOL WATERS THIS EVENING.  DVORAK
T-NUMBER ESTIMATES WERE 4.0 AND 3.5 FROM TAFB AND SAB...
RESPECTIVELY.  HOWEVER...THE CIMSS AMSU TECHNIQUE SUGGESTED ONLY 52
KT FROM A 2229Z AMSU PASS.  THIS LOWER VALUE IS CONSISTENT WITH AN
EARLIER QUIKSCAT PASS SHOWING ABOUT 50 KT MAXIMUM WINDS.  THE
INTENSITY ANALYSIS REMAINS AT 50 KT.  A 1738Z ASCAT PASS...THOUGH
IT MISSED BORIS' CENTER...DID CONFIRM THAT THE 34 KT WIND RADII HAS
NOT CHANGED SUBSTANTIALLY.

BORIS' TRACK CONTINUES OFF TO THE NORTHWEST AT ABOUT 7-8 KT.  ALL OF
THE GUIDANCE SUGGESTS AN IMMEDIATE TURN TOWARD THE WEST...BUT THE
MODELS HAVE BEEN TOO QUICK IN MAKING THIS TURN OVER THE LAST COUPLE
OF RUNS.  THE CONTINUED NORTHWEST MOVEMENT TODAY LIKELY IS THE
RESULT OF THE COMBINATION OF A STILL DEEP TROPICAL CYCLONE ALONG
WITH THE RATHER VIGOROUS MID-UPPER LEVEL TROUGH NORTHWEST OF BORIS. 
BUT IF THE STORM IS INDEED ABOUT TO LOSE ITS DEEP CONVECTION...AND
IT IS ANTICIPATED HERE THAT IT WILL...THEN THE TURN TO THE WEST AND
THEN WEST-SOUTHWEST SHOULD MATERIALIZE.  THE TRACK FORECAST IS
WEIGHTED MORE TOWARD PERSISTENCE AT 12 HR AND THEN PRIMARILY UPON
GFS...NOGAPS...UKMET...AND HWRF AT LONGER TIME PERIODS.  THIS TRACK
IS SLIGHTLY NORTH OF THE PREVIOUS FORECAST THROUGH 72 HR.

BORIS WILL BE MOVING OVER SSTS OF 23C SHORTLY...AS INDICATED BY THE
EXTENSIVE STRATOCUMULUS FIELD JUST TO ITS NORTHWEST.  IT MAY VERY
WELL BE THAT TONIGHT'S CONVECTIVE REINVIGORATION OF BORIS IS ITS
LAST GASP BEFORE SUCCUMBING TO THE NEGATIVE THERMODYNAMICS.  THE
INTENSITY FORECAST...QUITE SIMILAR TO THE PREVIOUS PREDICTION...IS
BASED UPON THE CONSENSUS OF SHIPS...LGEM...AND GFDL MODELS.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      03/0300Z 17.7N 128.3W    50 KT
 12HR VT     03/1200Z 18.0N 129.1W    45 KT
 24HR VT     04/0000Z 18.2N 130.1W    35 KT
 36HR VT     04/1200Z 18.2N 130.9W    25 KT
 48HR VT     05/0000Z 17.9N 132.2W    20 KT...REMNANT LOW
 72HR VT     06/0000Z 17.0N 135.5W    20 KT...REMNANT LOW
 96HR VT     07/0000Z 15.5N 139.0W    20 KT...REMNANT LOW
120HR VT     08/0000Z 15.0N 142.5W    20 KT...REMNANT LOW
 
$$
FORECASTER LANDSEA/BEVEN
 
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