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Tropical Storm PHILIPPE (Text)

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TROPICAL STORM PHILIPPE DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
1100 PM AST MON SEP 26 2011
 
AN ASCAT PASS CAUGHT PHILIPPE AT 2304 UTC...AND THE HIGHEST WINDS
SHOWN IN THE SWATH WERE 40 KT WITHIN THE DEEP CONVECTION LOCATED TO
THE SOUTHEAST OF THE LOW-LEVEL CENTER.  THIS DATA SUGGESTS THAT THE
INITIAL INTENSITY IS 45 KT...WHICH IS SUPPORTED BY SATELLITE
INTENSITY ESTIMATES OF 45 KT FROM TAFB AND SAB.  THIS IS THE FIRST
REAL GROUND-TRUTH DATA WE HAVE RECEIVED OVER PHILIPPE IN A COUPLE
OF DAYS...AND THE LOWERING OF THE INTENSITY SHOULD BE SEEN MORE AS
AN ADJUSTMENT RATHER THAN A WEAKENING OF THE STORM.  NONETHELESS...
PHILIPPE IS EXPECTED TO MOVE INTO AN ENVIRONMENT OF INCREASING
SOUTHWESTERLY SHEAR OVER THE NEXT DAY OR SO...AND THAT SHOULD LIMIT
STRENGTHENING...IF NOT INDUCE SOME WEAKENING.  THE SHEAR COULD
DIMINISH BY DAY 3 AS THE CYCLONE MOVES INTO AN UPPER-LEVEL
COL...AND THAT COULD BE JUST ENOUGH TO KEEP PHILIPPE FROM
DEGENERATING INTO A REMNANT LOW.  THE NHC INTENSITY FORECAST HAS
BEEN LOWERED PRIMARILY DUE TO THE ADJUSTED INITIAL INTENSITY AND IS
CLOSE TO THE INTENSITY CONSENSUS ICON THROUGH 48 HOURS AND THE
SHIPS AND LGEM ON DAYS 3 THROUGH 5.

THE INITIAL MOTION IS 315 DEGREES AT 7 KT.  PHILIPPE IS FORECAST TO
ACQUIRE A LITTLE MORE WESTWARD COMPONENT TO ITS MOTION OVER THE
NEXT DAY OR TWO WHEN A LONGWAVE TROUGH TO THE NORTHWEST OF THE
CYCLONE LIFTS NORTH AND A MID-LEVEL ANTICYCLONE BUILDS NORTH OF THE
CAPE VERDE ISLANDS.  THERE CONTINUES TO BE DIVERGENCE IN THE TRACK
GUIDANCE AFTER 48 HOURS WITH SOME MODELS INDICATING A TURN TOWARD
THE NORTH AND NORTHEAST WHILE ANOTHER SET...FIRST SHOWN BY THE
ECMWF...MAINTAINS A NORTHWESTWARD MOTION.  SINCE PHILIPPE IS
FORECAST TO SLOWLY WEAKEN...IN THE OFFICIAL FORECAST ANYWAYS...IT
SHOULD BECOME BLOCKED BY HIGH PRESSURE TO ITS NORTH AND WOULD MOST
LIKELY FOLLOW THE WESTERN CLUSTER OF MODELS.  THE OFFICIAL FORECAST
IS THEREFORE A LITTLE WEST OF THE PREVIOUS FORECAST AND THE TVCA
CONSENSUS...AND EVEN SHOWS A SLIGHT WESTWARD BEND AT DAY 5.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/0300Z 15.9N  34.8W   45 KT  50 MPH
 12H  27/1200Z 16.5N  35.5W   45 KT  50 MPH
 24H  28/0000Z 17.4N  36.6W   45 KT  50 MPH
 36H  28/1200Z 18.3N  38.1W   40 KT  45 MPH
 48H  29/0000Z 19.5N  39.4W   40 KT  45 MPH
 72H  30/0000Z 22.0N  41.0W   35 KT  40 MPH
 96H  01/0000Z 24.0N  41.5W   35 KT  40 MPH
120H  02/0000Z 25.0N  42.0W   35 KT  40 MPH
 
$$
FORECASTER BERG
 
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