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| #1156051 (Received by flhurricane at: 11:08 AM 05.Oct.2023) TCDAT2 Tropical Storm Philippe Discussion Number 49 NWS National Hurricane Center Miami FL AL172023 1100 AM AST Thu Oct 05 2023 Philippe`s low-level circulation remains broad this morning with most of the associated deep convection located within the eastern semicircle. Despite the continued disorganized structure, an Air Force Reserve Hurricane Hunter mission this morning measured peak 850-mb flight-level winds of 56 kt and SFMR surface winds of 40-45 kt. Based on these data, Philippe`s initial intensity is raised to 45 kt. The latest fixes suggest that Philippe is moving just west of due north (355 degrees) at 10 kt. This northward motion, with an increase in forward speed, is expected to continue through Saturday while Philippe moves over the western Atlantic between a deep-layer trough east of Florida and a mid-level high over the central Atlantic. A north-northwestward turn is likely to occur as the cyclone is approaching Atlantic Canada or eastern New England, due to a larger trough approaching from the west. Since Philippe may interact with a baroclinic zone and a developing non-tropical low to its west in another day or two, the nuances of the track forecast still need to be worked out, but nearly all of the track guidance agrees on the forecast scenario described above. The NHC forecast is close to the HCCA consensus aid and brings the center to the coast of Nova Scotia, New Brunswick, or eastern Maine between 60 and 72 hours. The center should then be absorbed by a broad area of low pressure to its west over Quebec some time on Sunday. Little change in intensity is expected during the next day or two, particularly since model guidance suggests that the shear over Philippe could strengthen further. Despite the shear, some additional strengthening is possible in about 48 hours when Philippe could receive an injection of baroclinic energy from the trough located east of Florida. That process should also kick-start extratropical transition, and the NHC forecast shows the transition complete by 60 hours (late Saturday) when Philippe is located offshore of Nova Scotia. Weakening is forecast once Philippe moves inland, and it`s likely that the strongest winds from the system will continue to occur on the eastern side of the circulation, primarily over parts of Atlantic Canada. KEY MESSAGES: 1. Tropical storm conditions are expected on Bermuda beginning early Friday morning, and a Tropical Storm Warning remains in effect. Heavy rainfall will also begin to affect the island today, which could produce flash-flooding. 2. Philippe is expected to move over portions of Atlantic Canada and eastern New England as a post-tropical cyclone this weekend. Regardless of Philippe`s intensity or structure, interests in those areas should be prepared for the possibility of strong winds and heavy rainfall and monitor statements from their local weather office. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 25.6N 66.3W 45 KT 50 MPH 12H 06/0000Z 27.7N 66.4W 45 KT 50 MPH 24H 06/1200Z 30.9N 66.3W 45 KT 50 MPH 36H 07/0000Z 34.2N 66.6W 50 KT 60 MPH 48H 07/1200Z 37.6N 66.6W 50 KT 60 MPH 60H 08/0000Z 41.8N 66.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 08/1200Z 47.4N 68.0W 40 KT 45 MPH...POST-TROP/INLAND 96H 09/1200Z...DISSIPATED $$ Forecaster Berg |
