Hurricane EPSILON

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TROPICAL STORM EPSILON DISCUSSION NUMBER  20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
4 AM EST SUN DEC 04 2005
 
WATER VAPOR IMAGERY SHOWS DRY AIR PENETRATING THE SOUTHWEST QUADRANT
OF THE CIRCULATION UNDERNEATH THE CIRRUS CANOPY...AND THE EYEWALL
CONVECTION HAS THINNED TO THE SOUTH OF THE CENTER. DATA T NUMBERS
FROM TAFB AND SAB ARE NOW BELOW HURRICANE STRENGTH...AND EPSILON IS
DOWNGRADED TO A TROPICAL STORM ON THIS BASIS.  
 
THE INITIAL MOTION IS 090/11.  EPSILON CONTINUES TO BE EMBEDDED IN A
WEAK WESTERLY STEERING CURRENT.  A BAROCLINIC ZONE TO THE NORTHWEST
OF EPSILON IS ALSO MOVING EASTWARD...BUT MORE RAPIDLY THAN THE
TROPICAL CYCLONE.  THIS ZONE IS FORECAST BY THE GLOBAL MODELS TO
PASS NEAR BUT NORTH OF EPSILON IN ABOUT 36 HOURS OR SO...AFTER
WHICH HIGH PRESSURE IS FORECAST TO BUILD IN...BLOCKING EPSILON'S
PATH.  MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON A SOUTHWESTWARD
TURN AFTER 48 HOURS.  THE UKMET IS STILL SOMETHING OF AN OUTLIER
FOR THE FIRST 48 HOURS WITH AN EAST-NORTHEASTERLY TRACK.  THE
OFFICIAL FORECAST DISCOUNTS THE UKMET...WHICH MISSED YESTERDAY'S
EASTWARD MOTION...AND IS BASED ON A CONSENSUS OF THE
GFS...GFDL...AND NOGAPS MODELS.

ON THE FORECAST TRACK...WATER TEMPERATURES WILL DECREASE ONLY
SLIGHTLY OVER THE NEXT COUPLE OF DAYS...AND THE GFDL SHOWS LITTLE
CHANGE IN STRENGTH DURING THIS TIME.  EPSILON HAS CARVED OUT FOR
ITSELF A LITTLE POCKET OF MODERATE SHEAR...OF ABOUT 20-25 KT
ACCORDING TO THE LATEST ANALYSIS FROM UW/CIMSS.  HIGHER VALUES
EXIST IN THE NEAR ENVIRONMENT OF THE CYCLONE THOUGH...AND IF THE
AFOREMENTIONED DRY AIR CONTINUES TO WEAKEN THE CORE CONVECTION THEN
EPSILON COULD QUICKLY FIND ITSELF OVERTAKEN BY THE SHEAR AND
DEGENERATE TO A NON-CONVECTIVE REMNANT LOW WITHIN A COUPLE OF DAYS. 
IT IS POSSIBLE THAT EPSILON COULD BECOME EXTRATROPICAL BEFORE
THAT...WHEN THE BAROCLINIC ZONE APPROACHES IN ABOUT 36 HOURS.
  
FORECASTER FRANKLIN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/0900Z 34.3N  40.4W    60 KT
 12HR VT     04/1800Z 34.3N  38.4W    55 KT
 24HR VT     05/0600Z 34.2N  36.3W    45 KT
 36HR VT     05/1800Z 34.0N  34.4W    40 KT...EXTRATROPICAL
 48HR VT     06/0600Z 33.0N  33.0W    35 KT...REMNANT LOW
 72HR VT     07/0600Z 30.0N  35.0W    25 KT...REMNANT LOW
 96HR VT     08/0600Z 26.0N  39.0W    25 KT...REMNANT LOW
120HR VT     09/0600Z 22.0N  44.0W    25 KT...REMNANT LOW
 
 
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