Hurricane EARL

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HURRICANE EARL DISCUSSION NUMBER  27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
1100 PM AST TUE AUG 31 2010

EARL REMAINS A WELL-ORGANIZED HURRICANE ON SATELLITE IMAGES.  AN EYE
OF ABOUT 20 N MI IN DIAMETER IS EVIDENT ON THE INFRARED IMAGES...
AND THE UPPER-LEVEL OUTFLOW IS WELL-DEFINED OVER ALL BUT THE
SOUTHWEST PART OF THE CIRCULATION...AS CONFIRMED BY SURVELLIANCE
DATA FROM THE NOAA G-IV JET THIS EVENING.  THE INITIAL INTENSITY IS
KEPT AT 115 KT BASED ON A DVORAK ESTIMATE FROM TAFB.  THERE IS
CURRENTLY ABOUT 20 KT OF SOUTHWESTERLY SHEAR OVER EARL AS DEPICTED
BY UW-CIMSS ANALYSES.  THIS SHEAR SHOULD LESSEN AS AN UPPER-LEVEL
TROUGH...JUST TO THE WEST AND NORTHWEST OF THE HURRICANE...IS
PREDICTED BY THE GLOBAL MODELS TO SHIFT WESTWARD OVER THE NEXT DAY
OR SO.  THIS EVOLUTION OF THE UPPER-LEVEL ENVIRONMENT SHOULD ALLOW
EARL TO MORE OR LESS MAINTAIN ITS INTENSITY FOR ABOUT THE NEXT 36
HOURS.  THE NHC INTENSITY FORECAST IS ONLY A LITTLE ABOVE THE
STATISTICAL/DYNAMICAL LGEM GUIDANCE AND A LITTLE BELOW THE GFDL
HURRICANE MODEL GUIDANCE.  BY DAY 4...GLOBAL MODELS SHOW EARL
BECOME EMBEDDED WITHIN A BAROCLINIC ZONE WITH WELL-DEFINED THERMAL
ADVECTION SO EXTRATROPICAL TRANSITION SHOULD HAVE OCCURRED BY THAT
TIME.

THE TRACK HAS BEEN WOBBLING AS IS TYPICAL OF INTENSE HURRICANES BUT
THE MEAN MOTION OVER THE PAST 6 HOURS IS ABOUT 310/13.  THERE HAS
BEEN LITTLE CHANGE TO THE NHC FORECAST TRACK OR REASONING.  EARL IS
EXPECTED TO GRADUALLY TURN TO THE RIGHT AS IT MOVES AROUND THE
WESTERN PERIPHERY OF A MID-LEVEL SUBTROPICAL ANTICYCLONE FOR THE
NEXT COUPLE OF DAYS.  AFTERWARDS...A VIGOROUS MID-LATITUDE TROUGH
AT 500 MB WILL APPROACH THE EAST COAST AND SHOULD CAUSE THE
HURRICANE TO TURN TOWARD THE NORTH-NORTHEAST.  OF COURSE...THE
TIMING OF THIS TURN IS CRITICAL IN DETERMINING HOW CLOSE THE CENTER
WILL COME TO THE U.S. EAST COAST.  ONE SHOULD NOT FOCUS ON THE
EXACT FORECAST TRACK BECAUSE OF FORECAST UNCERTAINTY...AND ALSO
BECAUSE EARL IS A LARGE HURRICANE AND SIGNIFICANT IMPACTS CAN BE
WELL REMOVED FROM THE CENTER.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      01/0300Z 23.0N  69.9W   115 KT
 12HR VT     01/1200Z 24.5N  71.6W   115 KT
 24HR VT     02/0000Z 27.0N  73.5W   115 KT
 36HR VT     02/1200Z 29.8N  75.0W   115 KT
 48HR VT     03/0000Z 32.7N  75.2W   110 KT
 72HR VT     04/0000Z 39.0N  70.5W    90 KT
 96HR VT     05/0000Z 47.0N  62.0W    75 KT...POST-TROP/EXTRATROP
120HR VT     06/0000Z 56.0N  58.0W    50 KT...POST-TROP/EXTRATROP
 
$$
FORECASTER PASCH/KIMBERLAIN
 
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