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| #1245204 (Received by flhurricane at: 5:00 PM 17.Sep.2025) TCDAT2 Tropical Storm Gabrielle Discussion Number 3 NWS National Hurricane Center Miami FL AL072025 Issued by the NWS Weather Prediction Center College Park MD 500 PM AST Wed Sep 17 2025 The biggest change with Gabrielle today has been that the center has re-formed farther to the north compared with the previous advisory, similar to earlier model forecasts. While satellite imagery continues to indicate an elongated circulation with multiple embedded swirls, it has become better defined than this morning, and we have continued to make the center position on the advisory a mean of those swirls. A second scatterometer pass that intersected the northern semicircle of the storm after the 15Z advisory did show a large area of 40-45 kt winds. Therefore, the initial intensity has been increased to 45 knots, even though the system does not appear appreciably more organized. The first part of the track forecast has been shifted to the north based on the recent center re-formation. Gabrielle is moving northwestward now, and a west-northwestward to northwestward track is anticipated for the next few days due to steering from the subtropical ridge. The fundamental forecast question for both track and intensity is related to the wind shear Gabrielle will experience and the structural change. Little intensity change is shown for the next couple of days while the storm remains in a high-shear but high SST/instability environment. There actually appears to be good consensus that the shear will relax after Friday, but there are significant model differences on how much. This leads to a considerable amount of track and intensity spread as the forecast progresses into the weekend. Generally the models that relax the shear more substantially, to around 10 knots or less, show more intensification and a track to the right of model consensus. Since the NHC intensity forecast is a bit above the model average (similar to the last prediction), we favor a track forecast to the right of the model blend, more consistent with the HCCA corrected consensus, Google Deep Mind ensemble, and ECMWF ensemble. Overall, forecast confidence remains relatively low. Based on the recent trends, this system should pass well east and north of the Windward and Leeward Islands, but interests in Bermuda should monitor forecasts during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 17/2100Z 19.4N 48.0W 45 KT 50 MPH 12H 18/0600Z 20.6N 49.7W 45 KT 50 MPH 24H 18/1800Z 21.7N 51.6W 45 KT 50 MPH 36H 19/0600Z 22.7N 53.5W 45 KT 50 MPH 48H 19/1800Z 23.5N 55.5W 45 KT 50 MPH 60H 20/0600Z 24.7N 57.4W 50 KT 60 MPH 72H 20/1800Z 26.2N 59.0W 55 KT 65 MPH 96H 21/1800Z 29.0N 62.0W 65 KT 75 MPH 120H 22/1800Z 32.0N 62.5W 75 KT 85 MPH $$ Forecaster Lamers/Blake |
