[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 052056
TCDAT2

TROPICAL STORM PHILIPPE DISCUSSION NUMBER  47
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
500 PM AST WED OCT 05 2011

THE OVERALL ORGANIZATION OF PHILIPPE HAS IMPROVED SLIGHTLY.  A 1753
UTC TRMM OVERPASS SHOWS THAT THE CENTER REMAINS NEAR THE
NORTHWESTERN EDGE OF THE MAIN CONVECTIVE MASS...WITH SOME INCREASE
IN BANDING EVIDENT IN THE MICROWAVE IMAGERY.  IN ADDITION...RECENT
GEOSTATIONARY IMAGERY INDICATES THAT CONVECTION HAS RECENTLY
DEVELOPED OVER THE NORTHWESTERN PORTION OF THE CIRCULATION FOR THE
FIRST TIME IN SEVERAL DAYS.  HOWEVER...DVORAK SATELLITE ESTIMATES
STILL SUPPORT AN INITIAL INTENSITY OF AROUND 55 KT.  IT SEEMS THAT
THE SHEAR OVER THE CYCLONE IS FINALLY DECREASING AS PREDICTED AND
PHILIPPE HAS A VERY SMALL WINDOW OF OPPORTUNITY FOR STRENGTHENING.
THE REDUCTION IN SHEAR IS EXPECTED TO BE SHORT-LIVED AS STRONG
WESTERLY UPPER-LEVEL WINDS ASSOCIATED WITH A LARGE MID-LATITUDE
TROUGH MOVING INTO THE WESTERN ATLANTIC IMPINGE UPON THE CYCLONE ON
THURSDAY.  AFTER THAT...THE SHEAR IS FORECAST TO INCREASE FURTHER
AND PHILIPPE WILL ALSO BE INTERACTING WITH A FRONT IN 2 TO 3 DAYS.
THE OFFICIAL INTENSITY FORECAST IS AT OR JUST ABOVE THE STATISTICAL
GUIDANCE DURING THE NEXT COUPLE OF DAYS...BUT IS MUCH BELOW THE
MORE AGGRESSIVE HWRF AND GFDL MODELS.  BY 72 HOURS...THE GLOBAL
MODELS UNANIMOUSLY SHOW PHILIPPE BECOMING EXTRATROPICAL AND SO DOES
THE OFFICIAL FORECAST.

PHILIPPE HAS TURNED NORTHWARD WITH AN INITIAL MOTION OF 360/5 KT.
THE TRACK FORECAST REASONING REMAINS UNCHANGED FROM THE PREVIOUS
ADVISORY.  PHILIPPE IS EXPECTED TO TURN NORTHEASTWARD AND
ACCELERATE AHEAD OF THE AFOREMENTIONED TROUGH DURING THE NEXT
COUPLE OF DAYS.  THE TRACK GUIDANCE IS IN RELATIVELY GOOD
AGREEMENT...HOWEVER THE GUIDANCE IS A LITTLE SLOWER THAN 6 HOURS AGO
IN MOVING THE EXTRATROPICAL CYCLONE NORTHEASTWARD BETWEEN DAYS 4
AND 5.  AS A RESULT...THE NEW TRACK SHOWS LESS NORTHEASTWARD MOTION
THAN THE PREVIOUS ADVISORY NEAR THE END OF THE FORECAST PERIOD.

FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 25.8N  61.3W   55 KT  65 MPH
 12H  06/0600Z 26.6N  61.1W   60 KT  70 MPH
 24H  06/1800Z 27.8N  59.9W   65 KT  75 MPH
 36H  07/0600Z 28.8N  57.9W   60 KT  70 MPH
 48H  07/1800Z 29.9N  55.2W   55 KT  65 MPH
 72H  08/1800Z 35.0N  48.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
 96H  09/1800Z 41.5N  44.0W   55 KT  65 MPH...POST-TROP/EXTRATROP
120H  10/1800Z 45.0N  41.0W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
FORECASTER BROWN


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