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| #1154874 (Received by flhurricane at: 5:13 AM 28.Sep.2023) TCDAT2 Tropical Storm Philippe Discussion Number 20 NWS National Hurricane Center Miami FL AL172023 500 AM AST Thu Sep 28 2023 Philippe remains a disorganized, sheared storm. Deep convection has continued through the night to the southeast of the estimated low-level center. Imagery from a 0525 UTC satellite microwave pass showed a decent curved band associated with this convection in the 89 GHz channel. Unfortunately, ASCAT missed the storm entirely. The initial intensity is held at 45 kt for this advisory, closest to the TAFB Dvorak estimate. There is still low confidence in Philippe`s track forecast. As stated in previous advisories, the future location of the storm is closely linked to its structure and intensity. Should Philippe remain a weaker, shallower cyclone, it is more likely to follow the low-level westerly to southwesterly flow. This advisory favors that scenario and shows the storm slowly drifting generally westward to southwestward through day 4. By day 5, global models are suggesting a trough to the north will lift Philippe or its remnants northwestward. A complicating factor to this track forecast is the proximity of an area of disturbed weather to the east of the cyclone. Some models are still showing a binary interaction between the two systems, which will largely depend on the strength of each. Significant changes have been made to the most recent track forecast, that are largely related to a slower westward progression of Philippe. Still, this forecast is a blend of the previous advisory and the latest model guidance. Further adjustments may be required in subsequent advisories. Philippe is in an environment with moderate southwesterly vertical wind shear and lower, upshear, mid-level relative humidities. These conditions are likely to inhibit intensification in the near-term time frame. In about 48 h, global models predict the vertical wind shear to increase and likely cause Philippe to gradually weaken through the forecast period. However, there remains higher-than-average uncertainty in the intensity forecast. The latest NHC forecast still calls for Philippe to become a remnant low by day 4. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 18.8N 54.6W 45 KT 50 MPH 12H 28/1800Z 19.1N 55.4W 45 KT 50 MPH 24H 29/0600Z 19.3N 56.0W 45 KT 50 MPH 36H 29/1800Z 19.2N 56.5W 40 KT 45 MPH 48H 30/0600Z 18.9N 57.1W 40 KT 45 MPH 60H 30/1800Z 18.5N 57.6W 35 KT 40 MPH 72H 01/0600Z 18.0N 58.3W 35 KT 40 MPH 96H 02/0600Z 18.2N 59.3W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 03/0600Z 19.0N 60.0W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Bucci |
