[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 011455
TCDAT2
HURRICANE EARL DISCUSSION NUMBER  29
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
1100 AM EDT WED SEP 01 2010


VISIBLE SATELLITE IMAGES THIS MORNING SHOW THAT EARL HAS A DISTINCT
EYE SURROUNDED BY MODERATE TO STRONG CONVECTION. A BLEND BETWEEN
SATELLITE INTENSITY ESTIMATES AND DATA FROM A NOAA RECONNAISSANCE
PLANE SUGGEST THAT WINDS ARE STILL 110 KNOTS.  GIVEN THE CURRENT
SATELLITE PRESENTATION...WHICH SHOWS A DECREASE IN THE SHEAR SINCE
YESTERDAY AND THE WARM OCEAN ALONG THE TRACK OF EARL...THERE IS A
POSSIBILITY THAT THE HURRICANE COULD REGAIN SOME INTENSITY.
HOWEVER...MOST OF THE GUIDANCE WITH THE EXCEPTION OF THE GFDL MODEL
SHOWS A STEADY STATE OR GRADUAL WEAKENING DURING THE NEXT DAY OR
TWO...AND THIS TREND IS FOLLOWED IN THE OFFICIAL FORECAST. AFTER
48 HOURS...EARL SHOULD BEGIN TO MOVE OVER COOLER WATERS AND
ENCOUNTER INCREASING SHEAR RESULTING IN WEAKENING. BY DAY 5 THE
HURRICANE SHOULD HAVE BEEN ABSORBED BY A LARGE EXTRATROPICAL
CYCLONE WELL NORTH OF CANADA.

SATELLITE AND RECONNAISSANCE AIRCRAFT FIXES INDICATE THAT THE
INITIAL MOTION IS TOWARD THE NORTHWEST OR 320 DEGREES AT 15 KNOTS.
THE SUBTROPICAL RIDGE THAT HAS BEEN STEERING EARL TOWARD THE
NORTHWEST IS ALREADY SHIFTING EASTWARD...AND LATER TODAY...EARL
SHOULD BE ON THE WESTERN SIDE OF THE RIDGE TURNING GRADUALLY
NORTHWARD. IN 36 HOURS OR SO...THE HURRICANE WILL ENCOUNTER THE
BASE OF THE MID-LATITUDE WESTERLIES AND SHOULD BEGIN TO RECURVE OR
TURN TO THE NORTHEAST WITH AN INCREASING FORWARD SPEED. THIS IS THE
SOLUTION UNANIMOUSLY PROVIDED BY TRACK MODELS...WHICH HAVE EARL
PASSING TO THE EAST BUT NOT FAR FROM THE OUTER BANKS OF NORTH
CAROLINA BETWEEN 36 AND 48 HOURS. ONLY A SMALL WESTWARD DEVIATION
TO THE TRACK TO THE WEST WOULD BRING THE CORE OF THE HURRICANE
TO THE COAST.

GIVEN THE FORECAST TRACK AND THE LARGE WIND RADII ASSOCIATED WITH A
EARL...A HURRICANE WARNING WAS REQUIRED FOR A PORTION OF THE NORTH
CAROLINA COAST.


FORECAST POSITIONS AND MAX WINDS

INITIAL      01/1500Z 25.1N  72.1W   110 KT
 12HR VT     02/0000Z 27.0N  73.7W   110 KT
 24HR VT     02/1200Z 29.8N  75.0W   110 KT
 36HR VT     03/0000Z 32.8N  75.2W   110 KT
 48HR VT     03/1200Z 36.0N  73.6W   100 KT
 72HR VT     04/1200Z 44.0N  66.0W    70 KT
 96HR VT     05/1200Z 55.0N  60.0W    50 KT...POST-TROP/EXTRATROP
120HR VT     06/1200Z...ABSORBED BY A LARGER EXTRATROPICAL CYCLONE

$$
FORECASTER AVILA


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