Tropical Storm GREG

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TROPICAL STORM GREG DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT FRI AUG 12 2005
 
THE CIRCULATION CENTER OF GREG HAS BECOME PARTIALLY EXPOSED NORTH OF
THE DEEP CONVECTION. UNIVERSITY OF WISCONSIN-CIMSS WIND SHEAR
PRODUCT DEPICTS A SYNOPTIC SCALE ANTI-CYCLONE SITUATED OVER
HURRICANE FERNANDA GENERATING 20 TO 30 KT OF NORTHERLY SHEAR ALONG
GREG'S PATH. WATER VAPOR IMAGERY SUGGESTS DRIER MID/UPPER LEVEL AIR
IS UNDERCUTTING THE OUTFLOW. CLOUD TOPS ASSOCIATED WITH THE
DISPLACED CONVECTION HAVE SIGNIFICANTLY WARMED OVER THE PAST 6
HOURS AS WELL. SATELLITE CLASSIFICATION ESTIMATES ARE 30 KT FROM
AFWA AND 35 KT FROM TAFB AND SAB. THE INITIAL INTENSITY IS
DECREASED TO 35 KT.

THE INTENSITY FORECAST CONTINUES TO BE PUZZLING. THE GFDL IS THE
ONLY MODEL THAT STRENGTHENS GREG TO A HURRICANE...IN 48 HOURS. THE
FSU SUPERENSEMBLE NOW INDICATES SOME STRENGTHENING BELOW HURRICANE
STRENGTH...TO 60 KT IN 48 HOURS.  THE SHIPS MODEL CONTINUES TO
SUGGEST TROPICAL STORM STRENGTH THROUGH DAY 5. SHIPS DOES INDICATE
LIGHT TO MODERATE NORTH TO NORTHEASTERLY SHEAR THROUGH 48 HOURS
BEFORE BECOMING SOUTHEASTERLY. THE OFFICIAL FORECAST IS A LITTLE
LESS GENEROUS THAN THE PREVIOUS FORECAST...GRADUALLY INCREASING
GREG TO HURRICANE STRENGTH BY DAY 2....MAINTAINING 65 KT THROUGH
THE REMAINDER OF THE FORECAST.  THIS IS BASICALLY A BLEND OF THE
SUPERENSEMBLE AND SHIPS SOLUTIONS.
 
THE INITIAL MOTION ESTIMATE IS 290/5. LOW-MID LEVEL EASTERLY
STEERING CURRENTS ARE EXPECTED TO PERSIST THROUGH THE FORECAST.
THE OFFICIAL FORECAST TRACK FOLLOWS THE GUNS CONSENSUS MODEL...WHICH
INCLUDES THE UKMET/NOGAPS AND THE GFDL. THE GFS CONTINUES TO
INDICATE ERRONEOUS BINARY INTERACTION WITH ANOTHER LOW TO THE EAST
OF GREG.  THEREFORE...CONU AND THE GUNA WHICH INCLUDE THE GFS WERE
NOT FACTORED INTO THE FORECAST.

FORECASTER ROBERTS/STEWART
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/0300Z 14.6N 113.7W    35 KT
 12HR VT     13/1200Z 14.6N 114.2W    40 KT
 24HR VT     14/0000Z 14.5N 114.8W    45 KT
 36HR VT     14/1200Z 14.3N 115.5W    55 KT
 48HR VT     15/0000Z 14.1N 116.5W    65 KT
 72HR VT     16/0000Z 14.1N 119.0W    65 KT
 96HR VT     17/0000Z 14.0N 122.5W    65 KT
120HR VT     18/0000Z 14.0N 126.0W    65 KT
 
 
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