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Subtropical Depression ANDREA (Text)

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SUBTROPICAL DEPRESSION ANDREA DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL012007
1100 AM EDT THU MAY 10 2007
 
DEEP CONVECTION IS DISAPPEARING QUICKLY AND ONLY A FEW THUNDERSTORMS
REMAIN IN THE NORTHEASTERN QUADRANT.  IT IS THEREFORE NO SURPRISE
THAT THE STRONGEST FLIGHT-LEVEL WINDS MEASURED AT 1000 FT BY THE
AIR FORCE RECONNAISSANCE AIRCRAFT THIS MORNING WERE LESS THAN 40
KT.  ANDREA IS DOWNGRADED TO A SUBTROPICAL DEPRESSION WITH 30 KT
MAXIMUM WINDS.  A COMEBACK SEEMS UNLIKELY IN THE DRY AND STABLE
ENVIRONMENT...COMBINED WITH NORTHWESTERLY WIND SHEAR...DEPICTED IN
WATER VAPOR IMAGERY.  A CONTINUED DECLINE IS FORECAST...AND UNLESS
DEEP CONVECTION REDEVEOPS SOON...ANDREA WILL PROBABLY NO LONGER
QUALIFY AS A DEPRESSION BY TOMORROW OR PERHAPS EARLIER.  A REMNANT
LOW CIRCULATION MIGHT PERSIST FOR A COUPLE OF DAYS BEYOND THEN.  IT
IS WORTH NOTING THAT ALL OF THE DYNAMICAL MODELS FORECAST
EXTRATROPICAL CYCLOGENESIS FARTHER NORTH OVER THE WESTERN ATLANTIC
IN ABOUT THREE DAYS.  THE GFDL IS THE ONLY ONE THAT KEEPS ANDREA
INTACT LONG ENOUGH TO MOVE NORTHEASTWARD AND EVENTUALLY BECOME THIS
EXTRATROPICAL CYCLONE...AND WHILE THIS SOLUTION IS NOT
IMPOSSIBLE...IT IS DISCOUNTED IN THE OFFICIAL FORECAST.

ANDREA CONTINUES TO DRIFT SOUTHWARD AND MOST MODELS INDICATE THIS
WILL CONTINUE FOR THE NEXT DAY OR TWO.  THE OFFICIAL FORECAST NOW
HINTS AT AN EASTWARD MOTION BEGINNING ON DAY TWO AS THE LONGWAVE
SYNOPTIC PATTERN BECOMES A LITTLE MORE PROGRESSIVE...BUT THE
OVERALL MOTION THROUGH 48 HOURS IS EXPECTED TO BE MINIMAL.
 
THE TROPICAL STORM WATCH ALONG THE SOUTHEAST U.S. COAST IS BEING
DISCONTINUED.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/1500Z 29.9N  79.9W    30 KT
 12HR VT     11/0000Z 29.6N  79.9W    30 KT
 24HR VT     11/1200Z 29.3N  79.8W    25 KT...DISSIPATING
 36HR VT     12/0000Z 29.2N  79.6W    25 KT...REMNANT LOW
 48HR VT     12/1200Z 29.5N  79.3W    20 KT...REMNANT LOW
 72HR VT     13/1200Z...DISSIPATED
 
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FORECASTER KNABB
 
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