Tropical Depression GABRIELLE

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TROPICAL DEPRESSION GABRIELLE DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
1100 PM EDT MON SEP 10 2007

DESPITE A RATHER HARSH UPPER-LEVEL WIND ENVIRONMENT...GABRIELLE IS
HANGING ON AS A TROPICAL CYCLONE AS IT MOVES OVER THE WARM WATERS
OF THE NORTHERN PORTION OF THE GULF STREAM.  EARLIER IR IMAGERY AND
LIGHTENING DATA SHOWED SOME RESURGENCE OF DEEP CONVECTION OVER THE
SOUTHEAST QUADRANT OF THE SYSTEM BUT RECENTLY THIS ACTIVITY HAS
DIMINISHED AND IS BEING SHEARED AWAY FROM THE CENTER.  DVORAK
SATELLITE INTENSITY ESTIMATES RANGE FROM 25 TO 30 KT AND A RECENT
QUIKSCAT PASS SHOWS NO VELOCITIES GREATER THAN 30 KT. 
THEREFORE...THE INITIAL INTENSITY WILL REMAIN 30 KT.  THE FORECAST
TRACK TAKES THE CENTER ALONG THE NORTHERN WALL OF THE GULF STREAM
AND THE CYCLONE COULD PASS OVER ONE OF THE ASSOCIATED WARM CORE
RINGS.  ALTHOUGH THIS WOULD FAVOR SOME RESTRENGTHENING...THE
INCREASINGLY HOSTILE UPPER-LEVEL FLOW SHOULD PRECLUDE SIGNIFICANT
INTENSIFICATION.  IN 24 HOURS OR SO...THE GFS SHOWS THE SYSTEM
INTERACTING WITH A WARM FRONT EXTENDING FROM AN EXTRATROPICAL
CYCLONE OVER SOUTHEASTERN CANADA AND GABRIELLE IS LIKELY TO BECOME
ABSORBED BY THAT CYCLONE AFTER 36 HOURS...IF NOT SOONER.

THE FORWARD SPEED IS INCREASING AND THE INITIAL MOTION IS ABOUT
075/17.  GABRIELLE IS EXPECTED TO BE STEERED BY THE FLOW TO THE
SOUTHEAST OF A MID-TROPOSPHERIC TROUGH APPROACHING THE NORTHEASTERN
UNITED STATES...AND TO THE NORTH OF AN ANTICYCLONE IN THE VICINITY
OF BERMUDA.  THE OFFICIAL FORECAST IS VERY SIMILAR TO THE PREVIOUS
ONE...AND IS A LITTLE TO THE SOUTH OF THE U.K. MET AND GFS TRACKS...
BUT CLOSE TO THE ECMWF SOLUTION.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/0300Z 38.1N  68.8W    30 KT
 12HR VT     11/1200Z 39.1N  65.9W    30 KT
 24HR VT     12/0000Z 40.5N  61.5W    30 KT
 36HR VT     12/1200Z 43.0N  56.0W    30 KT
 48HR VT     13/0000Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER PASCH/ROBERTS
 
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