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| #46648 (Received by flhurricane at: 11:31 PM 17.Sep.2005) TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT SAT SEP 17 2005 CONVENTIONAL AND MCIROWAVE SATELLITE IMAGERY SUGGEST TROPICAL STORM PHILIPPE HAS MOVED VERY LITTLE TO THE NORTH-NORTHWEST DURING THE PAST 6 HOURS. A 17/2154Z QUIKSCAT OVERPASS SHOWED THE SURFACE CENTER WEST OF 55W LONGITUDE...WHEREAS THE RECON POSITION NEAR THAT TIME INDICATED A CIRCULATION CENTER EAST OF 55W. MY FEELING IS THAT THE RECON CENTER WAS A SMALL CIRCULATION ROTATING NORTHWARD UP THE EAST SIDE OF THE LARGER LOW-LEVEL CENTER...AND THAT THE TWO CENTERS HAVE NOW CONSOLIDATED NEAR 55W. A BURST OF DEEP CONVECTION HAS DEVELOPED OVER AND SOUTH OF THE ALLEGED LOW-LEVEL CENTER...AND SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB...35 KT FROM SAB...AND 25 KT FROM AFWA. DUE TO THE UNCERTAINTY IN THE EXACT LOCATION OF THE CENTER...THE INITIAL INTENSITY IS AN AVERAGE OF THE VARIOUS INTENSITY ESTIMATES. A RECON AIRCRAFT WILL BE INVESTIGATING PHILIPPE AROUND 06Z. THE INITIAL MOTION IS AN UNCERTAIN 335/4. STEERING CURRENTS ARE UNUSUALLY WEAK FOR THIS REGION OF THE ATLANTIC...AND PHILIPPE IS EXPECTED TO MOVE SLOWLY NORTHWESTWARD AROUND THE SOUTHWESTERN PERIPHERY OF A WEAK MID-LEVEL RIDGE THROUGHOUT THE FORECAST PERIOD. BY THE END OF THE PERIOD...THE RIDGE IS FORECAST TO STRENGTHEN TO THE NORTH OF THE CYCLONE...AND THAT MAY RESULT IN A MORE WEST-NORTHWESTWARD MOTION THAN WHAT IS INDICATED BY THE OFFICIAL FORECAST. THE NHC MODEL GUIDANCE IS RATHER DIVERGENT...BUT IS IN GENERAL AGREEMENT ON THE FORECAST MOTION AND THE FORECAST TRACK IS CLOSE TO THE MODEL CONSENSUS. PHILIPPE IS FORECAST TO REMAIN OVER 30C AND WARMER SSTS FOR THE NEXT 5 DAYS...AND THE VERTICAL SHEAR IS EXPECTED TO BE LESS THAN 15 KT. THEREFORE...STEADY STRENGTHENING IS FORECAST SIMILAR TO THE PREVIOUS ADVISORY AND THE LATEST SHIPS MODEL OUTPUT. BASED ON THE MORE EASTWARD SHIFT IN THE FORECAST TRACK...WATCHES OR WARNINGS ARE NOT ANTICIPATED AT THIS TIME FOR ANY PORTION OF THE LESSER ANTILES. HOWEVER...WITH STEERING CURRENTS BEING RATHER WEAK AND ILL-DEFINED...ANY WESTWARD SHIFT COULD REQUIRE WATCHES OR WARNINGS AT SOME POINT IN THE FORECAST PERIOD. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 18/0300Z 14.1N 55.2W 35 KT 12HR VT 18/1200Z 14.9N 55.7W 40 KT 24HR VT 19/0000Z 15.8N 56.4W 50 KT 36HR VT 19/1200Z 17.0N 57.3W 60 KT 48HR VT 20/0000Z 18.1N 58.3W 65 KT 72HR VT 21/0000Z 20.6N 59.9W 75 KT 96HR VT 22/0000Z 23.0N 61.0W 85 KT 120HR VT 23/0000Z 25.0N 62.0W 95 KT |
