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| #1155744 (Received by flhurricane at: 11:04 AM 03.Oct.2023) TCDAT2 Tropical Storm Philippe Discussion Number 41 NWS National Hurricane Center Miami FL AL172023 1100 AM AST Tue Oct 03 2023 Philippe`s center has become exposed to the northwest of the deep convection, and visible satellite images from this morning suggest that it has lost definition. This is confirmed by the crew from an ongoing Air Force Reserve Hurricane Hunter aircraft, which indicated a center uncertainty of 10 n mi. The plane has only measured a peak 850-mb flight-level wind of 41 kt and SFMR winds of 35-40 kt mainly within the southeastern quadrant over the waters between the northern Leeward Islands. Dropsonde data also indicate the pressure has risen to 1004 mb. Based on these data, Philippe`s initial intensity is set at 40 kt. Philippe has sped up a bit, although it has not yet begun to turn to right. The current motion is barely northwestward (305 degrees) at 9 kt, with the center now passing just to the northeast of Anegada Island in the British Virgin Islands. The track guidance insists that Philippe will turn toward the north-northwest later today as it moves around the western periphery of a mid-level high over the central Atlantic. However, the shallow, sheared structure of the cyclone may cause it to remain on the western side of the guidance envelope in the short term, potentially delaying any northward turn. The guidance is in good agreement that the northward turn will eventually occur, but then there are significant speed differences as the storm moves across the western Atlantic. Primarily due to the storm`s resistance to begin turning, the new NHC track forecast has been shifted about 45-50 n mi to the west of the previous prediction, but it lies very close to the latest TVCA and HCCA consensus aids. Except for HWRF and HMON (which turn Philippe to the east), the rest of the guidance is in more agreement that the storm may approach Atlantic Canada in about 5 days. Moderate to strong shear is expected to persist over Philippe for awhile. Therefore, little change in strength is expected during the next day or two. The upper-level environment may become a little more conducive for strengthening when Philippe moves northward over the western Atlantic, but confidence in that occurring is still quite low. The NHC intensity forecast continues to show some modest strengthening and is close to the HCCA consensus aid. Global models fields, as well as phase-space diagrams, indicate that Philippe could acquire frontal features as it is approaching Atlantic Canada, and the NHC forecast therefore shows it becoming post-tropical by day 5. KEY MESSAGES: 1. Tropical storm conditions are expected to continue on Anguilla and are possible on the British Virgin Islands through today. Strong gusty winds are also likely elsewhere in the Leeward Islands today. 2. Heavy rainfall from Philippe is expected to produce scattered flash flooding across portions of the northern Leeward Islands and the British Virgin Islands into early Wednesday. FORECAST POSITIONS AND MAX WINDS INIT 03/1500Z 18.9N 63.9W 40 KT 45 MPH 12H 04/0000Z 19.8N 64.4W 40 KT 45 MPH 24H 04/1200Z 21.2N 65.0W 40 KT 45 MPH 36H 05/0000Z 22.9N 65.4W 40 KT 45 MPH 48H 05/1200Z 24.8N 65.6W 45 KT 50 MPH 60H 06/0000Z 27.3N 65.2W 45 KT 50 MPH 72H 06/1200Z 30.1N 64.4W 50 KT 60 MPH 96H 07/1200Z 35.5N 63.3W 55 KT 65 MPH 120H 08/1200Z 41.7N 63.0W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg |
