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| #1154755 (Received by flhurricane at: 11:01 AM 27.Sep.2023) TCDAT2 Tropical Storm Philippe Discussion Number 17 NWS National Hurricane Center Miami FL AL172023 1100 AM AST Wed Sep 27 2023 Visible, infrared and microwave imagery depicts that Philippe is a slightly better organized system this morning. A burst of deep convection continues near and east of the center. In addition, earlier AMSR and SSMI/S microwave passes show that a convective band has been developing on the eastern side of the circulation. However, visible satellite images within the past hour depict that the low-level center is becoming partially exposed on the western edge of the convection. Subjective and objective satellite intensity estimates have increased this cycle, with a TAFB Dvorak data-T number of 3.0, 45 kt. Given the developing banding feature and satellite intensity estimates, the initial intensity is raised to 45 kt for this advisory. This is also in agreement with a recent ASCAT-B pass. Philippe is expected to remain in a sheared environment over the next few days. However, the GFS SHIPS vertical wind shear forecast shows a slight decrease, which may allow to the storm to withhold convection near the low-level center a little longer than what was previously anticipated. Philippe is forecast to move into a slightly drier mid-level airmass in a few days, which may also inhibit the overall convective pattern. Some slight fluctuations in intensity may occur due to the pulsing convective nature of the system during the next few days, with an overall slow weakening trend later this weekend. The NHC intensity forecast was raised slightly given the initial higher intensity. There remains uncertainty in the intensity forecast and it is possible Philippe maintains its tropical cyclone status as it reaches the northern Leeward Islands. The storm has not gained much latitude this morning and continues to move mainly westward at around 280/8 kt. Philippe is currently being steered by the flow around a weak mid-level ridge and is expected to move west-northwestward over the next couple of days. In the latter part of the forecast period, the weakening and shallow system should turn toward the west-southwest. The track forecast is highly dependent on the intensity forecast, however. The official track forecast has again been shifted southward in 3-5 days, but not as far south as the consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 27/1500Z 17.5N 53.7W 45 KT 50 MPH 12H 28/0000Z 18.0N 54.7W 45 KT 50 MPH 24H 28/1200Z 18.6N 56.1W 45 KT 50 MPH 36H 29/0000Z 19.0N 57.8W 40 KT 45 MPH 48H 29/1200Z 19.0N 59.5W 40 KT 45 MPH 60H 30/0000Z 18.9N 60.8W 35 KT 40 MPH 72H 30/1200Z 18.7N 62.2W 35 KT 40 MPH 96H 01/1200Z 18.4N 64.7W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 02/1200Z 18.1N 66.9W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Kelly |
