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| #47087 (Received by flhurricane at: 4:31 AM 20.Sep.2005) TCDAT2 HURRICANE PHILIPPE DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT TUE SEP 20 2005 PHILIPPE'S CLOUD PATTERN IS CHARACTERIZED BY A RATHER AMORPHOUS- LOOKING MASS OF VERY DEEP CONVECTION...ALTHOUGH RECENT SATELLITE IMAGES SUGGEST THAT IT MAY BE DEVELOPING SORT OF A COMMA SHAPE. THE LACK OF UPPER-LEVEL OUTFLOW OVER THE WESTERN SECTORS OF THE HURRICANE SUGGESTS SOME WESTERLY SHEARING...DUE TO THE FLOW AT THE BASE OF A BROAD UPPER-TROPOSPHERIC TROUGH ASSOCIATED WITH THE OUTFLOW TO THE EAST OF RITA. ALTHOUGH THE SHIPS MODEL ALSO DIAGNOSES SIGNIFICANT SHEAR AFFECTING PHILIPPE DURING THE FORECAST PERIOD...IT NONETHELESS PREDICTS SOME STRENGTHENING. THE OFFFICIAL FORECAST SIMILARLY SHOWS AN INCREASE IN STRENGTH UP TO 48 HOURS...BUT GOES A FAIR AMOUNT BELOW SHIPS THEREAFTER BECAUSE THE SHEAR IS EXPECTED TO BECOME SIMPLY TOO STRONG FOR PHILIPPE TO MAINTAIN ITS INTENSITY BY THAT TIME. I HAVE ESTIMATED THE CENTER TO BE WEST OF THE FIXES FROM THE VARIOUS AGENCIES...BOTH FOR CONTINUITY FROM THE PREVIOUS TRACK...AND THE PRESENCE OF WESTERLY SHEAR. TRACK FORECAST PHILOSPHY REMAINS ESSENTIALLY UNCHANGED FROM THE PAST FEW ADVISORY PACKAGES. PHILIPPE IS MOVING TOWARD A BREAK IN THE SUBTROPICAL RIDGE IN THE VICINITY OF 60W. LATE IN THE FORECAST PERIOD...A STRONG 500 MB SHORTWAVE TROUGH IS EXPECTED TO DIG SOUTHWARD FROM THE CANADIAN MARITIMES. THIS FEATURE SHOULD CAUSE PHILIPPE TO ACCELERATE NORTHEASTWARD BY DAYS 4-5. THE OFFICIAL TRACK FORECAST IS QUITE SIMILAR TO THE PREVIOUS ONE...AND ALONG THE GENERAL TRAJECTORY OF...BUT A LITTLE SLOWER THAN...THE DYNAMICAL MODEL CONSENSUS. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 20/0900Z 18.8N 56.8W 70 KT 12HR VT 20/1800Z 19.8N 57.2W 70 KT 24HR VT 21/0600Z 21.3N 57.6W 75 KT 36HR VT 21/1800Z 23.0N 58.1W 80 KT 48HR VT 22/0600Z 25.0N 58.6W 85 KT 72HR VT 23/0600Z 29.5N 59.5W 75 KT 96HR VT 24/0600Z 34.0N 58.0W 65 KT 120HR VT 25/0600Z 38.0N 52.0W 60 KT |
