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515 
WTNT42 KNHC 221506
TCDAT2
HURRICANE DEBBY DISCUSSION NUMBER  12
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT TUE AUG 22 2000
 
AN EYE FEATURE HAS CONTINUED TO SPIN UP AND SPIN DOWN IN ABOUT 3
HOURS INCREMENTS OVER THE PAST 24 HOURS...AND RECON AND RADAR DATA
INDICATE THAT DEBBY MAY BE WRAPPING UP AN EYE AGAIN.  OUTFLOW HAS
IMPROVED DURING THE PAST 12 HOURS AND THE OVERALL CONVECTIVE PATTERN
HAS BECOME MORE CIRCULAR.

INITIAL MOTION ESTIMATE IS 290/19.  HOWEVER...RECENT RECON AND RADAR
REPORTS SUGGEST THAT DEBBY MAY BE MAKING ANOTHER WOBBLE TO THE WEST
AND IS CURRENTLY PASSING OVER THE VIRGIN ISLANDS...AND THE SOUTHERN
EYEWALL MAY JUST SKIRT THE NORTHEAST COAST OF PUERTO RICO THIS
AFTERNOON.  IN THE LONGER TERM...MOST OF THE MODEL GUIDANCE HAS
SHIFTED A LITTLE MORE POLEWARD WITH THE UKMET MODEL SLOWLY TRACKING
DEBBY NORTHWARD THROUGH THE CENTRAL BAHAMAS IN 48 TO 72 HOURS.   ALL
OF THE GLOBAL MODELS MAINTAIN A WEAKNESS IN THE 500 MB RIDGE AXIS
OVER THE SOUTHEAST U.S. AND BAHAMAS...BUT THE UKMET DIGS THE
NORTHERN U.S. TROUGH FURTHER SOUTH THAN ANY OF THE OTHER MODELS. 
HOWEVER...EVEN THE UKMET MODEL MAINTAINS THE SURFACE TO 700 MB RIDGE
TO THE NORTH OF DEBBY THROUGH 72 HOURS.  AS A RESULT...THE OFFICIAL
TRACK MERELY SLOWS THE FORWARD SPEED DOWN TO 8 KT IN 72 HOURS RATHER
THAN RECURVING THE CYCLONE TO THE NORTH.  THE OFFICIAL TRACK IS JUST
NORTH OF THE PREVIOUS FORECAST AND A LITTLE SOUTH OF THE GFDL MODEL.
  
THE RAPID MOTION OF DEBBY SHOULD KEEP ANY SIGNIFICANT
INTENSIFICATION FROM OCCURRING FOR PROBABLY THE NEXT 24 HOURS...
AND IN 36 HOURS...SOME SOUTHERLY DOWNSLOPE FLOW OFF HISPANIOLA MAY
HINDER THE INTENSIFICATION PROCESS.  HOWEVER...BY THE 48 AND 72 HOUR
PERIODS...DEBBY SHOULD BE CLEAR OF ANY LAND EFFECTS AND BE OVER 29C
OR HIGHER SSTS. THE WARM WATER AND IMPRESSIVE OUTFLOW PATTERN WOULD
TEND TO FAVOR SIGNIFICANT INTENSIFICATION AND DEBBY COULD POSSIBLY
BECOME A MAJOR HURRICANE AT THAT TIME.  IN FACT...THE GFDL MODEL
TAKES DEBBY DOWN TO 937 MB IN 72 HOURS.  WE ARE FOLLOWING THE SHIPS
INTENSITY MODEL...WHICH HAS PERFORMED WELL...UNTIL THE INNER CORE OF
DEBBY BECOMES BETTER ORGANIZED.  FORECAST INTENSITIES MAY BE
ADJUSTED HIGHER IN THE AFTERNOON FORECAST.

FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     22/1500Z 18.5N  64.4W    65 KTS
12HR VT     23/0000Z 19.2N  67.0W    70 KTS
24HR VT     23/1200Z 20.3N  70.3W    75 KTS
36HR VT     24/0000Z 21.5N  73.2W    75 KTS
48HR VT     24/1200Z 22.5N  75.5W    80 KTS
72HR VT     25/1200Z 24.5N  78.5W    85 KTS