[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 280900
TCDAT2

TROPICAL STORM PHILIPPE DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
500 AM AST WED SEP 28 2011

DURING THE LAST SEVERAL HOURS DEEP CONVECTION HAS BEEN INCREASING IN
INTENSITY AND COVERAGE TO THE NORTH AND NORTHEAST OF THE CENTER OF
PHILIPPE. HOWEVER...THIS CONVECTION HAS BEEN UNABLE TO WRAP AROUND
THE CIRCULATION DUE TO ABOUT 20 KT OF SOUTHWESTERLY SHEAR. THE
INITIAL WIND SPEED IS HELD AT 35 KT FOR THIS ADVISORY...IN
AGREEMENT WITH DVORAK CLASSIFICATIONS FROM TAFB AND ADT VALUES
FROM UW-CIMSS. OTHER THAN A BRIEF DECREASE IN THE WIND SHEAR IN
36-48 HOURS...THE SHIPS MODEL MAINTAINS SHEAR VALUES OF 20 KT OR
HIGHER OVER PHILIPPE DURING THE NEXT SEVERAL DAYS. ACCORDINGLY...
THE SHIPS AND LGEM MODELS SHOW LITTLE CHANGE IN STRENGTH OR A
SLIGHT WEAKENING THROUGHOUT THE FORECAST PERIOD. ON THE OTHER
HAND...THE FSSE...GFDL...AND HWRF MODELS CONTINUE TO INTENSIFY THIS
SYSTEM AND BRING PHILIPPE TO HURRICANE STRENGTH. THE LATTER
SCENARIO APPEARS HIGHLY UNLIKELY...AND THE OFFICIAL FORECAST
CLOSELY FOLLOWS THE SHIPS/LGEM GUIDANCE. PHILIPPE IS FORECAST TO
BECOME A REMNANT LOW BY DAY 4 WHEN THE SHEAR IS EXPECTED TO BE IN
EXCESS OF 30 KT.

PHILIPPE IS MOVING WEST-NORTHWESTWARD AT ABOUT 10 KT TO THE SOUTH OF
A NARROW MID-LEVEL RIDGE. THIS RIDGE IS EXPECTED TO WEAKEN DURING
THE NEXT COUPLE OF DAYS DUE TO THE AMPLIFICATION OF A LARGE-SCALE
TROUGH OVER THE NORTHEASTERN ATLANTIC...WHICH SHOULD CAUSE THE
CYCLONE TO TURN NORTHWESTWARD DURING THAT TIME PERIOD. BEYOND
THAT...PHILIPPE...OR ITS REMNANT LOW...IS EXPECTED TO TURN BACK
TOWARD THE LEFT AS THE SUBTROPICAL RIDGE RESTRENGTHENS. THE MODEL
GUIDANCE HAS SHIFTED A LITTLE MORE TO THE WEST THIS CYCLE...AND THE
OFFICIAL FORECAST FOLLOWS THAT TREND BUT IS TO THE RIGHT OF THE
MULTI-MODEL CONSENSUS.


FORECAST POSITIONS AND MAX WINDS

INIT  28/0900Z 16.5N  38.0W   35 KT  40 MPH
 12H  28/1800Z 17.2N  39.1W   35 KT  40 MPH
 24H  29/0600Z 18.4N  40.7W   30 KT  35 MPH
 36H  29/1800Z 19.8N  42.0W   30 KT  35 MPH
 48H  30/0600Z 21.2N  43.4W   30 KT  35 MPH
 72H  01/0600Z 23.2N  45.9W   30 KT  35 MPH
 96H  02/0600Z 24.5N  49.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  03/0600Z 25.5N  52.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
FORECASTER CANGIALOSI


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