[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 292052
TCDAT2
HURRICANE EARL DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
500 PM AST SUN AUG 29 2010

THE SATELLITE APPEARANCE OF EARL HAS CONTINUED TO IMPROVE THROUGHOUT
THE DAY.  SEVERAL CURVED BANDS OF THUNDERSTORMS ARE SEEN SURROUNDING
A CENTRAL DENSE OVERCAST FEATURE.  THERE ARE NO HINTS OF AN EYE IN
VISIBLE IMAGERY...HOWEVER AN EYE IS APPARENT IN RECENT RADAR
IMAGERY FROM GUADELOUPE AND WAS ALSO REPORTED BY THE AIRCRAFT A
FEW HOURS AGO.  ALTHOUGH THE PLANE DID NOT FIND HIGHER FLIGHT-LEVEL
OR SFMR WINDS THAN IT DID THIS MORNING...THE MINIMUM PRESSURE
REPORTED WAS LOWER ON EACH SUCCESSIVE FIX AND WAS DOWN TO 978 MB.
BASED ON SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY ESTIMATES...
AND THE INCREASED ORGANIZATION ON SATELLITE IMAGES...THE ADVISORY
INTENSITY HAS BEEN INCREASED TO 75 KT.  A NOAA P-3 AIRCRAFT ON A
RESEARCH MISSION SHOULD BE IN EARL SHORTLY...FOLLOWED BY THE NEXT
AIR FORCE C-130 MISSION BETWEEN 0000 AND 0600 UTC.

THE CENTER FIXES FROM THE AIRCRAFT FLIGHT TODAY YIELD AN INITIAL
MOTION OF ABOUT 285/12...A LITTLE SLOWER THAN BEFORE.  THE FORECAST
REASONING REMAINS UNCHANGED FROM THE PREVIOUS ADVISORY.  EARL IS
EXPECTED TO BE STEERED AROUND THE WESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE DURING THE NEXT COUPLE OF DAYS.  THE HURRICANE
SHOULD TURN NORTHWESTWARD IN 36-48 HOURS.  EARL IS FORECAST TO TURN
NORTHWARD...THEN NORTHEASTWARD AHEAD OF A TROUGH THAT MOVES INTO
GREAT LAKES REGION IN 4-5 DAYS.  THE TRACK GUIDANCE GENERALLY AGREES
WITH THIS SCENARIO...BUT THERE ARE SOME LARGE DIFFERENCES IN
THE FORWARD SPEED OF EARL AT DAYS 4 AND 5.  THE GLOBAL MODELS REMAIN
FASTER THAN THE GFDL/HWRF AND THE OFFICIAL CONTINUES TO BE FASTER
THAN THE DYNAMICAL MODEL CONSENSUS AFTER 72 HOURS.

THE GLOBAL MODELS SHOW A RATHER FAVORABLE UPPER-LEVEL ENVIRONMENT
FOR STRENGTHENING DURING THE NEXT COUPLE OF DAYS AS AN UPPER-LEVEL
ANTICYCLONE BUILDS OVER THE SYSTEM.  THE SHIPS...LGEM...AND GFDL
MODELS SHOW EARL REACHING MAJOR HURRICANE STRENGTH IN A DAY OR SO
AND THE OFFICIAL FORECAST FOLLOWS SUIT.  LATE IN THE FORECAST
PERIOD...THE HURRICANE IS EXPECTED TO BEGIN TO WEAKEN AS IT MOVES
OVER COOLER SSTS AND INTO AN AREA OF INCREASING SOUTHWESTERLY
SHEAR.


FORECAST POSITIONS AND MAX WINDS

INITIAL      29/2100Z 17.6N  59.5W    75 KT
 12HR VT     30/0600Z 18.0N  61.3W    90 KT
 24HR VT     30/1800Z 18.9N  63.3W   100 KT
 36HR VT     31/0600Z 20.3N  65.1W   110 KT
 48HR VT     31/1800Z 22.1N  66.9W   115 KT
 72HR VT     01/1800Z 27.3N  70.2W   115 KT
 96HR VT     02/1800Z 33.5N  71.5W   105 KT
120HR VT     03/1800Z 40.0N  68.0W    90 KT

$$
FORECASTER BROWN/BERG



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