Tropical Storm EPSILON

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TROPICAL STORM EPSILON DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
10 PM EST TUE NOV 29 2005
 
WHILE ITS POSITION NEAR THE CENTER OF A LARGE UPPER-LEVEL
LOW SUGGESTS THAT EPSILON HAS NOT FULLY SHED SUBTROPICAL
CHARACTERISTICS...THE LOW-LEVEL CENTER HAS REMAINED BENEATH THE
PERSISTENT CENTRAL CONVECTION DURING THE PAST SEVERAL HOURS. 
ADDITIONALLY...A TRMM OVERPASS AT 2051Z AND A QUIKSCAT OVERPASS AT
2155Z BOTH SUGGEST THAT THE CYCLONE HAS FORMED AN INNER WIND CORE
MORE CHARACTERISTIC OF A TROPICAL CYCLONE...WITH THE QUIKSCAT DATA
SHOWING 40 KT WINDS NEAR THE CENTER.  SATELLITE INTENSITY ESTIMATES
ARE SUBTROPICAL 45-50 KT FROM TAFB...AND TROPICAL 35 KT FROM SAB
AND AFWA.  BASED ON THE ABOVE...EPSILON REMAINS A 45 KT TROPICAL
STORM FOR THIS PACKAGE.  AN AMSU OVERPASS AT ABOUT 02Z MAY PROVIDE
MORE INFORMATION ON THE THERMAL STRUCTURE OF THE STORM.

THE INITIAL MOTION REMAINS 270/7.  EPSILON...AND THE UPPER-LEVEL LOW
IT IS EMBEDDED IN....ARE SOUTH OF A DEEP-LAYER RIDGE THAT IS MOVING
EASTWARD FROM SOUTHEASTERN CANADA INTO THE ATLANTIC.  THE LARGE-
SCALE MODELS FORECAST THIS RIDGE TO PASS NORTH OF THE CYCLONE
DURING THE NEXT 24 HR...THEN CONTINUE EASTWARD AND WEAKEN AS A
DEEP-LAYER TROUGH AND ASSOCIATED SURFACE CYCLONE MOVE INTO THE
EASTERN UNITED STATES AND NORTHWESTERN ATLANTIC.  THIS EVOLUTION
SHOULD STEER THE STORM WESTWARD FOR 12-24 HR...THEN ALLOW
RECURVATURE TOWARD THE NORTHEAST.  ALL THE TRACK GUIDANCE AGREES
WITH THIS SCENARIO THROUGH ABOUT 72 HR.  AFTER THAT TIME...THE GFS
AND NOGAPS MODELS FORECAST EPSILON TO MOVE MORE EASTWARD...WHILE
THE ECMWF...UKMET...AND CANADIAN MODELS CALL FOR A NORTHEASTWARD
MOTION.  THE OFFICIAL FORECAST WILL LIE BETWEEN THESE TWO EXTREMES
IN BEST AGREEMENT WITH THE GFDL.  OVERALL...THE NEW FORECAST TRACK
IS A LITTLE TO THE WEST AND NORTH OF THE PREVIOUS TRACK.
 
THE LARGE-SCALE MODELS FORECAST EPSILON TO REMAIN NEAR THE CENTER OF
THE UPPER-LEVEL LOW FOR 24-36 HR.  WHILE THIS IS NOT THE BEST PLACE
FOR TROPICAL CYCLONES FROM A THERMODYNAMIC STANDPOINT...THIS WILL
LIKELY KEEP THE VERTICAL SHEAR AT LIGHT TO MODERATE LEVELS AND
ALLOW SOME STRENGTHENING.  THE INTENSITY FORECAST THUS CALLS FOR
THE STORM TO REACH 60 KT IN 36 HR...WHICH IS A LITTLE STRONGER THAN
THE SHIPS GUIDANCE.  AFTER THAT...THE UPPER LOW SHOULD WEAKEN AND
MOVE EASTWARD...EXPOSING THE STORM TO SHEAR.  ALSO...THE FORECAST
NORTHEASTWARD TURN SHOULD BRING THE SYSTEM OVER SEA SURFACE
TEMPERATURES COLDER THAN THE CURRENTLY MARGINAL-AT-BEST 23C.  THIS
COMBINATION SHOULD CAUSE WEAKENING.  THEN...THE FRONTAL SYSTEM
ASSOCIATED WITH THE APPROACHING DEEP-LAYER TROUGH SHOULD BEGIN TO
MERGE WITH EPSILON IN ABOUT 72 HR...EVENTUALLY CAUSING THE STORM TO
BECOME EXTRATROPICAL.

THE TRMM AND QUIKSCAT DATA SUGGEST THE WIND FIELD OF EPSILON IS
ABOUT TO JOIN THE LARGE AREA OF NORTHEASTERLY FLOW LOCATED
NORTHWEST OF THE STORM.  IF THIS HAPPENS...THE WIND RADII IN THE
NORTHWESTERN QUADRANT MAY NEED SIGNIFICANT REVISION.  IN THE LONGER
TERM...THE SIZE OF THE 34 KT WIND FIELD AT 72 HR WAS REDUCED BASED
ON THE LARGE-SCALE MODELS NOT SHOWING A VIGOROUS OUTER ENVELOPE.
 
FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/0300Z 31.4N  51.9W    45 KT
 12HR VT     30/1200Z 31.4N  53.1W    50 KT
 24HR VT     01/0000Z 31.6N  53.9W    55 KT
 36HR VT     01/1200Z 32.0N  53.9W    60 KT
 48HR VT     02/0000Z 32.8N  53.0W    60 KT
 72HR VT     03/0000Z 34.5N  48.5W    55 KT...BECOMING EXTRATROPICAL
 96HR VT     04/0000Z 37.0N  43.5W    50 KT...EXTRATROPICAL
120HR VT     05/0000Z 40.5N  39.0W    40 KT...EXTRATROPICAL
 
 
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