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Tropical Depression DEBBY (Text)

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TROPICAL DEPRESSION DEBBY DISCUSSION NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042012
1100 PM EDT TUE JUN 26 2012

THE CENTER OF DEBBY MADE LANDFALL IN THE FLORIDA BIG BEND
REGION AT AROUND 2100 UTC.  SINCE THAT TIME...THE CENTER HAS TURNED
SOUTHEASTWARD...POSSIBLY DUE TO INTERACTION WITH A GUST FRONT FROM
THE MOST RECENT CONVECTIVE BURST AND A MESOSCALE VORTICITY CENTER
OVER NORTHEASTERN FLORIDA.  THE CIRCULATION HAS ALSO BECOME
ELONGATED WITH THE CENTRAL PRESSURE RISING TO AROUND 1000 MB.  THE
INITIAL INTENSITY OF 30 KT IS BASED ON COASTAL OBSERVATIONS AND THE
CHANCE THAT SOME STRONGER WINDS MAY EXIST OVER THE WATER.

THE INITIAL MOTION IS 125/6.  A DEEP-LAYER TROUGH IS NORTH AND
NORTHEAST OF DEBBY...AND AN ASSOCIATED SURFACE FRONTAL ZONE EXTENDS
FROM SOUTHERN GEORGIA EAST-NORTHEASTWARD INTO THE ATLANTIC.  WHILE
THE LARGE-SCALE MODELS FORECAST THESE FEATURES TO WEAKEN DURING THE
NEXT 72 HR...THEY AGREE THAT THERE WILL BE ENOUGH WESTERLY STEERING
FLOW TO ALLOW THE CENTER TO CROSS FLORIDA AND REACH THE ATLANTIC
DURING THE NEXT 24 HR OR SO.  THE MODELS DIVERGE AFTER THAT.  THE
NOGAPS AND CANADIAN MODELS SHOW THE CENTER STALLING OFF THE U. S.
COAST...WHILE THE GFS...UKMET...ECMWF...GFDL...AND HWRF MOVE IT
EAST-NORTHEASTWARD INTO THE ATLANTIC AT VARYING SPEEDS.  THE
FORECAST TRACK GOES WITH THE LATTER SCENARIO.  THE NEW FORECAST IS
ADJUSTED SOUTH OF THE PREVIOUS TRACK BASED ON THE INITIAL POSITION
AND MOTION...AND IS A BIT FASTER.  IT SHOULD BE NOTED THAT
ADDITIONAL ADJUSTMENTS TO THE TRACK FORECAST MAY BE NECESSARY IF
THE CENTER RE-FORMS WHILE CROSSING FLORIDA.

DEBBY IS CURRENTLY EXPERIENCING MODERATE VERTICAL WIND SHEAR...DRY
AIR ENTRAINMENT...AND LAND INTERACTION.  THIS COMBINATION SHOULD
PERSIST UNTIL THE CENTER REACHES THE ATLANTIC.  IN 36-48 HR...THE
GFS...UKMET...AND ECMWF FORECAST AN UPPER-LEVEL TROUGH TO INTERACT
WITH THE CYCLONE...WHICH COULD REDUCE THE SHEAR AND PROVIDE
FAVORABLE UPPER-LEVEL DIVERGENCE.  HOWEVER...DEEP-LAYER DRY AIR
SHOULD STILL BE NEAR DEBBY AT THAT TIME...WHICH COULD PREVENT THE
MORE FAVORABLE DYNAMICS FROM STRENGTHENING THE SYSTEM.  THUS...THE
NEW INTENSITY FORECAST IS ALMOST IDENTICAL TO THE PREVIOUS
FORECAST.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/0300Z 29.0N  82.8W   30 KT  35 MPH
 12H  27/1200Z 29.3N  81.7W   30 KT  35 MPH...INLAND
 24H  28/0000Z 29.7N  80.0W   30 KT  35 MPH...OVER WATER
 36H  28/1200Z 30.3N  77.8W   30 KT  35 MPH
 48H  29/0000Z 30.7N  75.6W   35 KT  40 MPH
 72H  30/0000Z 32.0N  72.5W   40 KT  45 MPH
 96H  01/0000Z 35.0N  69.0W   45 KT  50 MPH
120H  02/0000Z 39.0N  62.0W   45 KT  50 MPH
 
$$
FORECASTER BEVEN
 
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