Hurricane ISIS
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TROPICAL STORM ISIS DISCUSSION NUMBER 34
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT THU SEP 16 2004
CONVECTION ASSOCIATED WITH ISIS HAS DIMINISHED CONSIDERABLY THIS
MORNING...WITH ONLY ISOLATED CELLS REMAINING AT THIS TIME.
SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM SAB...AND 35 KT FROM
TAFB AND AFWA. BASED ON THIS...THE INITIAL INTENSITY IS REDUCED TO
40 KT...AND THIS MAY BE GENEROUS.
THE CENTER HAS BEEN RE-LOCATED TO THE SOUTH OF THE PREVIOUS POSITION
AND THE INITIAL MOTION IS A VERY DUBIOUS 280/2. DYNAMICAL MODEL
GUIDANCE IS IN SOMEWHAT BETTER AGREEMENT ON A WESTWARD TO
WEST-SOUTHWESTWARD DRIFT...AND THE OFFICIAL FORECAST WILL FOLLOW
THIS. THE NEW FORECAST TRACK IS SIMILAR TO...BUT SHIFTED SOUTH
OF...THE PREVIOUS ADVISORY BASED ON THE INITIAL POSITION.
ISIS IS OVER 25-26C SEA SURFACE TEMPERATURES...AND THE SATELLITE
IMAGERY SUGGESTS SOME SOUTHWESTERLY SHEAR HAS DEVELOPED. UNLESS
THE CONVECTION RETURNS...ADDITIONAL WEAKENING IS EXPECTED...WITH
ISIS BECOMING A DEPRESSION IN 12 HR AND A REMNANT LOW IN 48 HR.
THIS IS IN BEST AGREEMENT WITH THE GFDL FORECAST. THE SHIPS MODEL
CALLS FOR SOME REGENERATION WHEN THE SYSTEM DRIFTS INTO WARMER
WATER. THAT SOLUTION IS DISCOUNTED FOR THE MOMENT.
FORECASTER BEVEN
FORECAST POSITIONS AND MAX WINDS
INITIAL 16/1500Z 18.3N 132.6W 40 KT
12HR VT 17/0000Z 18.3N 133.0W 30 KT
24HR VT 17/1200Z 18.2N 133.5W 25 KT
36HR VT 18/0000Z 18.1N 134.0W 25 KT...DISSIPATING
48HR VT 18/1200Z 17.8N 134.7W 20 KT...REMNANT LOW
72HR VT 19/1200Z 17.5N 136.0W 20 KT...REMNANT LOW
96HR VT 20/1200Z 17.5N 137.5W 20 KT...REMNANT LOW
120HR VT 21/1200Z 17.5N 139.0W 20 KT...REMNANT LOW
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