[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 030247
TCDAT2

TROPICAL STORM PHILIPPE DISCUSSION NUMBER  36
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL172011
1100 PM AST SUN OCT 02 2011

BURSTS OF DEEP CONVECTION CONTINUE TO FORM NEAR THE WELL-DEFINED
CENTER OF PHILIPPE. HOWEVER...THE CONVECTION HAS BEEN UNABLE TO
SUSTAIN ITSELF IN THE FACE OF VERY STRONG UPPER-LEVEL WINDS FROM
THE NORTH. PHILIPPE MAY BE SOMEWHAT RESILIENT IN SPITE OF THE SHEAR
BECAUSE THE SHEAR IS CONFINED TO LEVELS ABOVE 300 MB INSTEAD OF
EXTENDING THROUGH THE DEPTH OF THE TROPOSPHERE. A BLEND OF DVORAK
T- AND CI-NUMBERS AND RECENT ADT VALUES SUGGESTS THAT PHILIPPE IS
MAINTAINING ITS STRENGTH...AND THE INTENSITY IS HELD AT 45 KT. THE
HOSTILE SHEAR AFFECTING PHILIPPE IS FORECAST TO GRADUALLY RELAX
DURING THE NEXT COUPLE OF DAYS...REACHING A RELATIVE MINIMUM IN
48-72 HOURS. THE OFFICIAL FORECAST SHOWS WEAKENING OVER THE NEXT
DAY OR SO UNTIL THE SHEAR WEAKENS...WITH SOME INTENSIFICATION
EXPECTED IN 2 TO 3 DAYS. AFTER THAT...INCREASING SOUTHWESTERLY
SHEAR...PERHAPS EVEN STRONGER THAN WHAT PHILIPPE IS EXPERIENCING
NOW...SHOULD RESULT IN WEAKENING. THE OFFICIAL INTENSITY FORECAST
IS NEAR THE INTENSITY CONSENSUS THROUGH DAY 3 BUT REMAINS A TAD
BELOW IT AT LATER TIMES. IT SHOULD BE NOTED THAT THE ECMWF SOLUTION
THAT CONTINUES TO INDICATE DISSIPATION IN 2-3 DAYS WHEN THE SHEAR
IS FORECAST TO DECREASE HAS BEEN DISCOUNTED.

RECENT FIXES INDICATE THAT PHILIPPE HAS CHANGED ITS HEADING. WHILE
THE INITIAL MOTION ESTIMATE IS 270/10...RECENT SATELLITE IMAGES
SUGGEST THAT A MOTION JUST SOUTH OF DUE WEST MAY HAVE ALREADY BEGUN.
GLOBAL MODELS KEEP PHILIPPE MOVING WESTWARD TO EVEN WEST-
SOUTHWESTWARD FOR THE NEXT DAY OR TWO TO THE SOUTH OF A MID-LEVEL
RIDGE OVER THE CENTRAL ATLANTIC. LATER IN THE FORECAST PERIOD...
PHILIPPE SHOULD TURN NORTHWARD AND EVENTUALLY NORTHEASTWARD UNDER
THE INFLUENCE OF INCREASING WESTERLY FLOW TO SOUTH OF A MID- TO
UPPER-LEVEL TROUGH OVER THE WEST-CENTRAL ATLANTIC. WHILE THE LARGE-
SCALE MODELS ARE IN GOOD AGREEMENT ON THIS SCENARIO...DIFFERENCES
ARE SEEN IN THE SHARPNESS AND TIMING OF THE TURN. THESE DIFFERENCES
ARE LARGELY RELATED TO THE LATITUDE OF THE STORM WHEN IT FIRST
ENCOUNTERS THIS DEEP-LAYER WESTERLY FLOW. THE UKMET AND NOGAPS...
WHICH KEEP THE PHILIPPE FARTHER NORTH...FAVOR A QUICKER AND SHARPER
TURN WHILE THE GFS AND REGIONAL MODELS...WHICH LIE FARTHER SOUTH
INITIALLY...DELAY THE TURN AND ARE NOT AS SHARP. THE NEW NHC TRACK
FORECAST IS NEAR THE MULTI-MODEL CONSENSUS AND GIVE THE MORE
SOUTHERLY GROUP OF GUIDANCE GREATER WEIGHT GIVEN RECENT TRENDS IN
THE OBSERVED MOTION.

FORECAST POSITIONS AND MAX WINDS

INIT  03/0300Z 26.1N  53.9W   45 KT  50 MPH
 12H  03/1200Z 25.9N  55.6W   40 KT  45 MPH
 24H  04/0000Z 25.6N  58.0W   40 KT  45 MPH
 36H  04/1200Z 25.5N  60.1W   35 KT  40 MPH
 48H  05/0000Z 26.1N  61.3W   40 KT  45 MPH
 72H  06/0000Z 27.8N  61.3W   50 KT  60 MPH
 96H  07/0000Z 30.2N  58.5W   45 KT  50 MPH
120H  08/0000Z 32.0N  55.0W   40 KT  45 MPH

$$
FORECASTER KIMBERLAIN



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