Issued at 1100 AM AST Fri Sep 19 2025
000 WTNT42 KNHC 191455 TCDAT2 Tropical Storm Gabrielle Discussion Number 10 NWS National Hurricane Center Miami FL AL072025 Issued by the NWS Weather Prediction Center College Park MD 1100 AM AST Fri Sep 19 2025 Gabrielle's low-level center remains mostly exposed, now between a large area of deep convection in the eastern semicircle and growing cells in the southwestern quadrant. There has been little change in the satellite estimates and since scatterometer missed the radius-of-maximum winds this morning, the initial intensity will remain 45 kt. The storm is moving northwestward or 305 degrees at 10 kt, with the subtropical ridge located to its north. A general pattern of troughing is expected to persist near the southeastern U.S. coast and far western Atlantic for the next several days, which is expected cause Gabrielle to recurve around the western periphery of the ridge over the next 4 days. While the track guidance remains relatively tight during this period, the along-track spread (speed differences) are quite large in the medium range. The HCCA and Google DeepMind (GDM) ensemble mean have bifurcated on the latest cycle with the corrected consensus to the north and the GDM to the south. Our forecast has adjusted slightly north, but remains on the southern side of the overall consensus. The reliable track models continue to show Gabrielle's center passing at least 140 n mi east of Bermuda in about 3 days. However, interests on the island should continue to monitor Gabrielle's progress since NHC's average track error at 3 days is about 90 n mi, and hazards can extend well away from the center. There remains a 20-25 percent chance of tropical-storm-force winds occurring on Bermuda. The moderate westerly shear currently affecting Gabrielle is forecast to gradually lessen below 10 kt by 24-36 hours. This should begin to mitigate the effects of surrounding dry air and allow for gradual strengthening. The NHC intensity forecast has once again been raised to trend toward the latest IVCN and HCCA consensus aids, and Gabrielle is expected to become a hurricane by Sunday. By day 5, the onset of significantly stronger shear and cooler waters should induce some weakening. There is significant uncertainty about when Gabrielle might become extratropical, as the forward speed of the system may contribute significantly to a higher peak intensity (longer time over warmer waters). KEY MESSAGES: 1. Gabrielle is forecast to become a hurricane by Sunday and pass east of Bermuda Sunday night and Monday. Interests on Bermuda should monitor Gabrielle's forecasts since it is too soon to specify the magnitude of potential wind and rainfall impacts. 2. Swells generated by Gabrielle are expected to reach Bermuda tonight and build through the weekend. These swells are likely to cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 21.9N 55.6W 45 KT 50 MPH 12H 20/0000Z 22.9N 56.9W 45 KT 50 MPH 24H 20/1200Z 24.3N 58.5W 50 KT 60 MPH 36H 21/0000Z 26.0N 59.8W 55 KT 65 MPH 48H 21/1200Z 27.8N 60.8W 65 KT 75 MPH 60H 22/0000Z 29.8N 61.2W 75 KT 85 MPH 72H 22/1200Z 32.0N 60.9W 85 KT 100 MPH 96H 23/1200Z 37.5N 54.0W 95 KT 110 MPH 120H 24/1200Z 41.3N 40.2W 75 KT 85 MPH $$ Forecaster Churchill/Blake
NHC Atlantic
