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| #1155577 (Received by flhurricane at: 10:58 AM 02.Oct.2023) TCDAT2 Tropical Storm Philippe Discussion Number 37 NWS National Hurricane Center Miami FL AL172023 1100 AM AST Mon Oct 02 2023 The center of Philippe has become exposed this morning with convection and heavy rainfall displaced to the south and southeast of the center as high northwesterly vertical wind shear persists. The initial intensity is held steady at 45 kt for this advisory, consistent with SFMR data from the Air Force Reserve reconnaissance aircraft mission showing a large area of 40-45 surface winds. Center fixes and 1-min visible imagery during the morning indicate that Philippe is moving erratically to the west-northwest (300 degrees) at 6 kt. The short-term part of track forecast is adjusted westward to match recent satellite trends, which necessitates the Tropical Storm Warning for Barbuda. After passing close to that island, Philippe is forecast to move northwest to north-northwest around the southwestern portion of a mid-level ridge over the subtropical Atlantic during the next couple of days. Around mid-week, Philippe should turn northward between the aforementioned ridge and a mid- to upper-level trough over the southwestern Atlantic. Beyond 96 hours, track uncertainty increases as to whether the ridge or trough will dominate, which is also partially connected to how strong Philippe becomes. Stronger solutions take the system on a more east-northeastward track at longer range while weaker solutions take the system more northward. Overall, the track forecast for this advisory was adjusted farther west than the previous advisory, after considering the latest ECMWF and ensemble aids. Strong northwesterly vertical wind shear is expected to prevent significant strengthening in the short term. In a couple of days, Philippe is expected to encounter a more favorable upper-level wind pattern as it moves northward over the Atlantic. This could allow for steady strengthening, and much of the guidance predicts that Philippe will become a hurricane in 3 to 4 days. The intensity forecast is consistent with the consensus aids, although the uncertainty is pretty high at long range given how Philippe has so far refused to intensify for days now. KEY MESSAGES: 1. Tropical storm conditions are expected across Barbuda and possible across Antigua beginning this evening while Philippe passes near or just northeast of the area. Interests elsewhere in the northern Leeward Islands should continue to monitor this system. 2. Heavy rainfall from Philippe could produce isolated to scattered flash flooding over the northern Leeward Islands, particularly across Barbuda and Antigua, through Tuesday. FORECAST POSITIONS AND MAX WINDS INIT 02/1500Z 17.1N 60.7W 45 KT 50 MPH 12H 03/0000Z 17.8N 61.5W 45 KT 50 MPH 24H 03/1200Z 18.9N 62.0W 50 KT 60 MPH 36H 04/0000Z 20.2N 62.4W 50 KT 60 MPH 48H 04/1200Z 21.8N 62.7W 50 KT 60 MPH 60H 05/0000Z 23.5N 62.8W 55 KT 65 MPH 72H 05/1200Z 25.3N 62.9W 60 KT 70 MPH 96H 06/1200Z 29.2N 61.5W 70 KT 80 MPH 120H 07/1200Z 32.5N 59.5W 75 KT 85 MPH $$ Forecaster Blake/Stevenson |
