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TROPICAL STORM ISIDORE DISCUSSION NUMBER  32
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT MON SEP 23 2002

SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE THAT ISIDORE HAS 
MOVED VERY LITTLE OVER THE PAST SEVERAL HOURS.  IT IS STILL EXPECTED 
THAT A MID-TROPOSPHERIC RIDGE WILL BUILD TO THE EAST OF THE TROPICAL 
CYCLONE...AND FORCE A GENERALLY NORTHWARD MOTION OVER THE NEXT 
COUPLE OF DAYS.  GUIDANCE FROM THE NCEP GLOBAL FORECAST 
SYSTEM...GFS...SHOWS A SOMEWHAT FASTER MOTION AND IS A LITTLE TO THE 
EAST OF THE PREVIOUS MODEL RUN.  IT IS NOT CLEAR WHAT IS CAUSING 
THIS CHANGE...BUT PERHAPS SOME OF THE EARLIER OBSERVATIONS FROM THE 
NOAA G-IV JET HAVE BEEN ASSIMILATED IN THE 18Z RUN OF THE GFS.  THE 
JET DATA SHOULD BE COMPLETELY UTILIZED IN THE NEXT...OOZ...RUN SO WE 
SHALL SOON SEE WHETHER THE FASTER AND MORE NORTHEASTWARD MOTION IS 
CONFIRMED.  FOR THIS ADVISORY...THE FORECAST TRACK IS ADJUSTED TO 
THE EAST AND IS SLIGHTLY FASTER THAN THAT FROM THE PREVIOUS 
ADVISORY...BUT IS STILL A LITTLE SLOWER AND WEST OF THE NEW GFS 
TRACK.  THE 36-48 HR FORECAST POINTS AND WIND FIELD SUGGEST THAT A 
HURRICANE WATCH MAY BE REQUIRED FOR THE NORTHERN GULF COAST ON 
TUESDAY MORNING...PROVIDES ISIDORE STARTS TO MOVE SOON.

ISIDORE IS BARELY A TROPICAL STORM...IF AT ALL.  STRONGEST WINDS ARE 
PROBABLY CONFINED TO A FEW SPOTS IN THE COASTAL WATERS AROUND 
YUCATAN...AND THE SYSTEM WILL PROBABLY BE DOWNGRADED TO A DEPRESSION 
ON THE NEXT ADVISORY.  HOWEVER SINCE THERE IS WEAK VERTICAL SHEAR 
AND A BROAD AREA OF UPPER-LEVEL ANTICYLONIC OUTFLOW OVER 
ISIDORE...RE-INTENSIFICATION SHOULD COMMENCE ONCE THE CENTER MOVES 
BACK OVER THE WATER.  THE BIG QUESTION IS HOW MUCH ISIDORE WILL 
RE-STRENGTHEN.  AS NOTED EARLIER...THIS DEPENDS LARGELY ON HOW SOON 
THE TROPICAL CYCLONE'S INNER CORE IS RE-ESTABLISHED.  ONCE THAT 
HAPPENS...ASSUMING IT DOES...SIGNIFICANT STRENGTHENING IS POSSIBLE.  
BEARING IN MIND THE GREAT UNCERTAINTIES IN INTENSITY FORECASTING... 
ISIDORE COULD BE NEAR CATEGORY TWO STRENGTH AS IT APPROACHES THE 
NORTHERN GULF COAST.
 
FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     24/0300Z 20.5N  89.3W    35 KTS
12HR VT     24/1200Z 21.8N  90.0W    40 KTS
24HR VT     25/0000Z 23.5N  90.7W    50 KTS
36HR VT     25/1200Z 25.4N  91.2W    65 KTS
48HR VT     26/0000Z 27.5N  91.5W    80 KTS
72HR VT     27/0000Z 32.5N  90.0W    30 KTS...INLAND
 
 
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