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Hurricane TOMAS (Text)

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HURRICANE TOMAS DISCUSSION NUMBER  30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL212010
1100 AM EDT FRI NOV 05 2010

BEFORE IT DEPARTED TOMAS...THE AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT REPORTED THAT THE CENTRAL PRESSURE HAD RISEN SLIGHTLY TO
987 MB.  HOWEVER...THE FLIGHT-LEVEL AND SFMR WINDS STILL SUPPORTED
AN INTENSITY OF 75 KT...WHICH IS THE INITIAL INTENSITY FOR THIS
ADVISORY.  THE CENTRAL CONVECTION IS CURRENTLY LOOKING A LITTLE
RAGGED IN SATELLITE IMAGERY AND RADAR DATA FROM CUBA...POSSIBLY DUE
TO THE CIRCULATION OF TOMAS INTERACTING WITH THE MOUNTAINS OF
HISPANIOLA.  THE CIRRUS OUTFLOW IS GOOD TO EXCELLENT OVER THE
NORTHERN SEMICIRCLE AND POOR ELSEWHERE.

THE INITIAL MOTION IS 030/10.  TOMAS IS TO THE EAST OF A STRONG
DEEP-LAYER TROUGH AND ASSOCIATED SURFACE FRONTAL SYSTEM OVER THE
EASTERN UNITED STATES AND THE WESTERN ATLANTIC.  FOR THE NEXT
36-48 HR...THIS FEATURE SHOULD STEER THE HURRICANE GENERALLY
NORTH-NORTHEASTWARD.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT WITH
THE DIRECTION OF MOTION...BUT THERE ARE DIFFERENCES IN SPEED
BETWEEN THE FASTER GFS/GFDL/HWRF AND THE SLOWER UKMET/ECMWF/NOGAPS. 
THIS PART OF THE FORECAST TRACK IS SIMILAR TO...BUT A LITTLE TO THE
LEFT OF...THE PREVIOUS TRACK...AND IN THE MIDDLE OF THE GUIDANCE
ENVELOPE.  AFTER 36-48 HR...THE GUIDANCE SHOWS SIGNIFICANT SPREAD
IN BOTH DIRECTION AND SPEED.  THE UKMET AND NOGAPS...WHICH APPEAR
TO SHEAR TOMAS APART...SHOW A SLOW EASTWARD MOTION SOUTH OF 25N. 
THE GFS/GFDL/HWRF MOVE TOMAS MUCH MORE QUICKLY TO THE NORTH OR
NORTHEAST AND ABSORB IT INTO THE BAROCLINIC SYSTEMS OVER THE
WESTERN ATLANTIC.   THE ECMWF IS IN BETWEEN...SHOWING AN EASTWARD
TURN FOLLOWED BY AN EAST-NORTHEASTWARD MOTION BY THE END OF THE
FORECAST PERIOD.  THIS PART OF THE NEW FORECAST TRACK LIES SOUTH OF
THE CENTER OF THE GUIDANCE ENVELOPE BETWEEN THE CONSENSUS MODELS
AND THE ECMWF...AND SHOWS A SLOWER FORWARD SPEED THE THE ECMWF. 
THIS PORTION OF THE TRACK FORECAST REMAINS LOW CONFIDENCE.
 
TOMAS STILL HAS ABOUT 24 HR IN WHICH TO STRENGTHEN BEFORE
ENCOUNTERING INCREASING VERTICAL WIND SHEAR AND DRIER AIR
ASSOCIATED WITH THE TROUGH...WITH THE CAVEAT THAT INTERACTION WITH
HISPANIOLA COULD SLOW OR HALT DEVELOPMENT.  THE SHIPS...LGEM...AND
GFDL MODELS NOW SHOW THE CYCLONE BECOMING A CATEGORY 2 HURRICANE IN
24 HR...AND THE NEW INTENSITY FORECAST WILL FOLLOW SUIT.  AFTER
THAT...THE CYCLONE IS EXPECTED TO ENCOUNTER HOSTILE ENOUGH
CONDITIONS TO CAUSE WEAKENING REGARDLESS OF THE EXACT TRACK IT
TAKES...AND THE FORECAST FOLLOWS THE TREND OF THE PREVIOUS ADVISORY
IN SHOWING A QUICK WEAKENING.  THE FINAL DEMISE OF TOMAS IS
DEPENDENT UPON ITS TRACK...AS A MORE NORTHWARD MOTION WOULD LIKELY
LEAD TO EXTRATROPICAL TRANSITION AND A MORE EASTWARD MOTION TO
DEGENERATION INTO A REMNANT LOW.  THE FORECAST WILL CONTINUE TO USE
THE LATTER SCENARIO FOR THE TIME BEING.
 
REGARDLESS OF THE EXACT TRACK AND INTENSITY OF TOMAS...THE MOST
SIGNIFICANT THREAT FROM THIS TROPICAL CYCLONE SHOULD CONTINUE TO BE
HEAVY RAINFALL...WHICH COULD PRODUCE FLASH FLOODING AND LIFE-
THREATENING MUD SLIDES OVER PORTIONS OF HAITI AND THE DOMINICAN
REPUBLIC DURING THE NEXT COUPLE OF DAYS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      05/1500Z 19.1N  74.4W    75 KT
 12HR VT     06/0000Z 20.8N  73.4W    80 KT
 24HR VT     06/1200Z 23.1N  72.1W    90 KT
 36HR VT     07/0000Z 25.1N  71.0W    80 KT
 48HR VT     07/1200Z 26.0N  69.9W    65 KT
 72HR VT     08/1200Z 27.5N  67.5W    40 KT
 96HR VT     09/1200Z 28.0N  64.5W    25 KT...POST-TROP/REMNT LOW
120HR VT     10/1200Z 29.0N  62.5W    25 KT...POST-TROP/REMNT LOW
 
$$
FORECASTER BEVEN
 
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