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| #1154455 (Received by flhurricane at: 10:53 AM 25.Sep.2023) TCDAT2 Tropical Storm Philippe Discussion Number 9 NWS National Hurricane Center Miami FL AL172023 1100 AM AST Mon Sep 25 2023 Visible satellite images indicate that Philippe has become less organized this morning. The low-level center has become fully exposed with all of the deep convection now displaced well to the east of the center. The initial wind speed is held at 45 kt, in agreement with most of the satellite intensity estimates. Philippe is currently experiencing about 20-25 kt of west-southwesterly vertical wind shear. Both the GFS- and ECMWF-based SHIPS models show the vertical wind shear increasing even more during the next few days. These hostile winds and dry air entrainment should cause Philippe to continue to struggle throughout the forecast period. There is some spread in the guidance with a couple of models showing slight strengthening and several of the models showing slight weakening. Based on the guidance and expected continued shear, the new forecast is lower than the previous one and shows no change in strength during the next several days. Geostationary and microwave satellite images indicate that Philippe has jogged to the left this morning. Smoothing through this wobble yields an initial motion of 280/11 kt. A turn back to the west-northwest is expected by tonight, followed by a northwestward motion in a couple of days as Philippe moves toward a weakness in the subtropical ridge. There is a vast amount of spread in the track models this morning with the GFS and its ensemble mean on the far right side of the guidance envelope and the ECMWF on the left side. An examination of the GFS model fields suggests that the model is showing a vortex that is likely too vertically aligned, and not representative of the environmental conditions. Therefore, that model is considered an outlier for the time being. The new NHC track forecast is adjusted to the left toward the various consensus models. FORECAST POSITIONS AND MAX WINDS INIT 25/1500Z 17.3N 45.5W 45 KT 50 MPH 12H 26/0000Z 17.6N 47.2W 45 KT 50 MPH 24H 26/1200Z 18.1N 49.2W 45 KT 50 MPH 36H 27/0000Z 18.9N 51.2W 45 KT 50 MPH 48H 27/1200Z 19.9N 52.9W 45 KT 50 MPH 60H 28/0000Z 21.1N 54.2W 45 KT 50 MPH 72H 28/1200Z 22.1N 55.4W 45 KT 50 MPH 96H 29/1200Z 23.7N 56.9W 45 KT 50 MPH 120H 30/1200Z 24.6N 57.9W 45 KT 50 MPH $$ Forecaster Cangialosi/Konarik |
