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| #1155790 (Received by flhurricane at: 4:46 PM 03.Oct.2023) TCDAT2 Tropical Storm Philippe Discussion Number 42 NWS National Hurricane Center Miami FL AL172023 500 PM AST Tue Oct 03 2023 Philippe has continued to lose organization for much of the day. Satellite images and aircraft fixes from this morning indicate that the circulation has become elongated, and the remaining deep convection has relatively little, if any, organization relative to the center, which is now located just north of the Virgin Islands. The initial intensity remains 40 kt based on the earlier SFMR data, but this could be generous given the overall loss of convective organization. The current motion is northwestward, or 310/10 kt. Over the next couple of days, Philippe is expected to turn northward between a strong mid-level high over the subtropical Atlantic and a developing cut-off low east of Florida, with its forward speed increasing in 2-3 days when it becomes positioned between these two features. The northward motion is expected to continue through the end of the forecast period as another deep-layer trough moves eastward across eastern North America. The most notable change in this NHC forecast is that the guidance has again shifted westward, both due to an adjustment caused by Philippe`s recent motion and a general westward trend in the track guidance. The official forecast is close to the TVCA consensus aid, but it`s not as far to the west as the latest ECMWF and HCCA solutions. The risk continues to increase for some form of Philippe, likely as a post-tropical cyclone, to reach Atlantic Canada or eastern New England in about 5 days. The deep-layer trough located near the east coast of the United States is likely to keep moderate-to-strong westerly or southwesterly shear over Philippe for much of the forecast period. As a result, little change in strength is forecast during the next 2-3 days. The GFS and ECMWF are now in good agreement that a separate baroclinic/non-tropical low will develop just to the west of Philippe in about 3 days. These two systems are likely to interact, with Philippe becoming attached to the warm front, and therefore becoming extratropical, by day 4. It`s possible that Philippe could strengthen slightly due to this baroclinic interaction, and that scenario is shown in the official forecast. KEY MESSAGES: 1. 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. 2. Gusty winds are likely to continue across portions of the northern Leeward Islands and the Virgin Islands through Wednesday. 3. The risk is increasing for tropical storm conditions to occur on Bermuda later this week. Interests on Bermuda should monitor the progress of Philippe. FORECAST POSITIONS AND MAX WINDS INIT 03/2100Z 19.6N 64.9W 40 KT 45 MPH 12H 04/0600Z 20.4N 65.4W 40 KT 45 MPH 24H 04/1800Z 22.0N 66.1W 40 KT 45 MPH 36H 05/0600Z 23.8N 66.6W 40 KT 45 MPH 48H 05/1800Z 26.2N 66.6W 40 KT 45 MPH 60H 06/0600Z 29.2N 66.0W 45 KT 50 MPH 72H 06/1800Z 32.2N 65.7W 45 KT 50 MPH 96H 07/1800Z 38.1N 66.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 08/1800Z 45.8N 66.9W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg |
