919 
 WTPZ42 KNHC 130255
 TCDEP2
 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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