[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 261434
TCDAT2

TROPICAL STORM PHILIPPE DISCUSSION NUMBER  10
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
1100 AM AST MON SEP 26 2011

DEEP CONVECTION HAS BEEN PULSING...BUT OVERALL THE CLOUD PATTERN OF
PHILIPPE HAS NOT CHANGED SIGNIFICANTLY OVER THE PAST SEVERAL HOURS.
MOST OF THE SHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING OVER THE
SOUTHERN PORTION OF THE CIRCULATION.  DVORAK CURRENT INTENSITY
ESTIMATES FROM TAFB AND SAB ARE UNCHANGED...AND THE INITIAL
INTENSITY IS HELD AT 50 KT.  THE STORM IS BEING AFFECTED BY
MODERATE WESTERLY SHEAR AND THE UPPER-LEVEL OUTFLOW IS RESTRICTED
OVER THE NORTHWEST QUADRANT.  SINCE THE SHEAR IS NOT FORECAST TO
DIMINISH...ONLY SLIGHT SHORT-TERM STRENGTHENING SEEMS POSSIBLE.
WATER VAPOR IMAGERY SHOWS INCREASING WESTERLY FLOW NORTH OF 20N
AND...IF THIS FLOW PERSISTS...PHILIPPE WILL BE MOVING INTO A MORE
HOSTILE ENVIRONMENT IN A COUPLE OF DAYS.  THE OFFICIAL WIND SPEED
FORECAST IS CONSERVATIVE AND ONLY SHOWS SLIGHT WEAKENING AFTER 24
HOURS...CLOSE TO THE LATEST LGEM GUIDANCE.  IT IS POSSIBLE...
HOWEVER...THAT THE CYCLONE COULD WEAKEN MORE THAN SHOWN HERE IN THE
LATTER PART OF THE FORECAST PERIOD.

PHILIPPE APPEARS TO HAVE TURNED SLIGHTLY TO THE RIGHT AND THE MOTION
ESTIMATE IS NOW 310/10.  THE STORM SHOULD MOVE ALONG THE
SOUTHWESTERN AND WESTERN PERIPHERY OF A MID-LEVEL ANTICYCLONE OVER
THE NEXT FEW DAYS.  BY DAYS 4 AND 5...AS A LARGE TROUGH AMPLIFIES
OVER THE EASTERN ATLANTIC NORTH OF 30N...MOST OF THE TRACK MODELS
TURN PHILIPPE SHARPLY TOWARD THE NORTHEAST.  THE ECMWF MODEL...WHICH
DEPICTS A WEAKER CYCLONE...IS AN OUTLIER IN THAT IT FORECASTS
PHILIPPE TO MOVE NORTHWESTWARD TO WEST-NORTHWESTWARD THROUGH THE
PERIOD.  SINCE THE CYCLONE COULD WEAKEN MORE THAN EXPECTED...THE
LATTER SCENARIO IS INDEED PLAUSIBLE.  FOR NOW...THE OFFICIAL
FORECAST IS CLOSE TO THE MULTI-MODEL CONSENSUS TRACK.

FORECAST POSITIONS AND MAX WINDS

INIT  26/1500Z 15.2N  34.2W   50 KT  60 MPH
 12H  27/0000Z 16.0N  35.1W   55 KT  65 MPH
 24H  27/1200Z 17.0N  36.1W   55 KT  65 MPH
 36H  28/0000Z 18.0N  37.1W   50 KT  60 MPH
 48H  28/1200Z 19.1N  38.2W   50 KT  60 MPH
 72H  29/1200Z 22.0N  40.0W   50 KT  60 MPH
 96H  30/1200Z 24.5N  40.0W   45 KT  50 MPH
120H  01/1200Z 26.0N  39.0W   45 KT  50 MPH

$$
FORECASTER PASCH


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