Tropical Storm PHILIPPE

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TROPICAL STORM PHILIPPE DISCUSSION NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
1100 PM AST TUE SEP 27 2011
 
SOUTHWESTERLY SHEAR CONTINUES TO TAKE ITS TOLL ON PHILIPPE.  DEEP
CONVECTION HAS BECOME QUITE LIMITED AND WHAT CONVECTION REMAINS IS
LOCATED WELL TO THE NORTHEAST OF THE CENTER.  HOWEVER...PHILIPPE IS
CONSERVATIVELY KEPT AS A TROPICAL STORM...BASED ON A RECENT DVORAK
CURRENT INTENSITY ESTIMATE OF 35 KT FROM TAFB.  THE SHEAR IS
EXPECTED TO REMAIN STRONG THROUGHOUT THE FORECAST PERIOD...EXCEPT
FOR A SMALL WINDOW BETWEEN ABOUT 36 AND 60 HOURS.  THE SHEAR ALONG
WITH MARGINAL SEA SURFACE TEMPERATURES AND SOME DRIER AIR TO THE
NORTHWEST OF THE CYCLONE IS LIKELY TO RESULT IN PHILIPPE BECOMING A
TROPICAL DEPRESSION. THE OFFICIAL INTENSITY FORECAST IS CLOSE TO
THE SHIPS/LGEM MODELS...AND MUCH BELOW THE DYNAMICAL GUIDANCE THAT
DEEPENS THE CYCLONE IN A FEW DAYS.  THE UPDATED FORECAST ALSO NOW
SHOWS PHILIPPE BECOMING A POST-TROPICAL REMNANT LOW IN 4-5
DAYS...WHEN THE SHEAR INCREASE FURTHER.  IF DEEP CONVECTION DOES
NOT REDEVELOP NEAR THE CENTER OVERNIGHT OR ON WEDNESDAY...THE
CYCLONE COULD BECOME A REMNANT LOW MUCH SOONER.
 
THE INITIAL MOTION ESTIMATE IS 285/8. PHILIPPE IS FORECAST TO MOVE
WEST-NORTHWESTWARD TO NORTHWESTWARD AROUND THE WESTERN PERIPHERY OF
A MID-LEVEL RIDGE TO ITS NORTHEAST.  AFTER 72 HOURS...A STRONG MID-
TO UPPER-LEVEL RIDGE IS FORECAST TO BUILD OVER THE NORTH-CENTRAL
ATLANTIC.  THIS RIDGE IS EXPECTED TO TURN PHILIPPE...OR ITS
REMNANTS...MORE TOWARD THE WEST LATER IN THE FORECAST PERIOD. THE
GUIDANCE HAS AGAIN SHIFTED WESTWARD AND THE NEW NHC TRACK HAS BEEN
ADJUSTED IN THAT DIRECTION.  THE NHC FORECAST LIES BETWEEN THE GFS
AND ECMWF MODELS AND IS IN BEST AGREEMENT WITH THE GFS ENSEMBLE
MEAN AND THE EXPERIMENTAL HFIP MULTI-MODEL CONSENSUS.
  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0300Z 16.1N  37.0W   35 KT  40 MPH
 12H  28/1200Z 16.5N  38.1W   30 KT  35 MPH
 24H  29/0000Z 17.7N  39.7W   30 KT  35 MPH
 36H  29/1200Z 19.1N  41.0W   30 KT  35 MPH
 48H  30/0000Z 20.6N  42.1W   30 KT  35 MPH
 72H  01/0000Z 22.8N  44.6W   30 KT  35 MPH
 96H  02/0000Z 24.5N  47.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  03/0000Z 25.5N  50.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 
$$
FORECASTER BROWN
 
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