Tropical Storm BORIS

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TROPICAL STORM BORIS DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP022008
800 PM PDT SUN JUN 29 2008
 
THE RAGGED EYE VISIBLE EARLIER HAS BEEN OBSCURED BY NEW CONVECTION
NEAR THE CENTER...ALTHOUGH EXCELLENT BANDING ALOFT IS APPARENT IN
AN AMSU PASS AT 0045 UTC.  THE ADVISORY INTENSITY OF 60 KT IS A
BLEND OF SUBJECTIVE DVORAK ESTIMATES OF 55 KT FROM TAFB AND SAB...A
CIMSS ADT OF 65 KT...AND A CIMSS AMSU ESTIMATE OF 66 KT.  THE
MICROWAVE IMAGERY IS NOT CONCLUSIVE BUT SUGGESTS A SMALL
DISLOCATION OF THE SURFACE AND UPPER CENTERS...IN LINE WITH THE
MODEST NORTHEASTERLY SHEAR STILL AFFECTING THE CYCLONE.  ALL OF THE
OBJECTIVE GUIDANCE...THE SHIPS...LGEM...HWRF...AND GFDL...INDICATE A
LITTLE MORE STRENGTHING WHILE THE CYCLONE IS OVER 27C WATERS...AND
THIS GUIDANCE IS REFLECTED IN THE OFFICIAL FORECAST.  A MORE STABLE
ENVIRONMENT AND COOLER WATERS LIE AHEAD...HOWEVER...WHICH SHOULD
RESULT IN A GRADUAL DECAY OF THE SYSTEM WITHIN A DAY OR SO.

THE INITIAL MOTION IS 270/9.  BORIS IS SOUTH OF A MID- TO
UPPER-LEVEL RIDGE...WHICH SHOULD CONTINUE TO PROVIDE A WESTWARD
STEERING CURRENT FOR THE NEXT DAY OR TWO.  AFTER THAT THERE IS
CONSIDERABLE UNCERTAINTY IN THE FORECAST TRACK.  THE GFDL AND GFS
SOLUTIONS SHOW BORIS TURNING BACK EASTWARD TO THE SOUTH OF THE
LARGE CYCLONIC DISTURBANCE CENTERED SOUTH OF ACAPULCO...WHILE THE
ECMWF AND NOGAPS MAINTAIN A MID-LEVEL RIDGE TO SUPPORT A WESTWARD
TRACK FOR THE NEXT 4-5 DAYS.  I NOTE THAT THE GFS IS ALREADY TOO
SLOW WITH THE WESTWARD MOTION...AND MAY BE OVERDOING THE
INTERACTION WITH THE EASTERN DISTURBANCE.  THE OFFICIAL FORECAST IS
CLOSE TO THE PREVIOUS TRACK...TO THE DYNAMICAL MODEL
CONSENSUS...AND IN PARTICULAR TO THE UKMET.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/0300Z 14.8N 118.3W    60 KT
 12HR VT     30/1200Z 14.8N 119.5W    65 KT
 24HR VT     01/0000Z 14.8N 120.9W    60 KT
 36HR VT     01/1200Z 14.7N 122.3W    55 KT
 48HR VT     02/0000Z 14.5N 123.5W    50 KT
 72HR VT     03/0000Z 14.0N 126.0W    40 KT
 96HR VT     04/0000Z 14.0N 127.0W    30 KT
120HR VT     05/0000Z 14.0N 128.0W    25 KT...REMNANT LOW
 
$$
FORECASTER FRANKLIN
 
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