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| #1108398 (Received by flhurricane at: 4:54 PM 22.Sep.2022) TCDAT3 Tropical Storm Gaston Discussion Number 10 NWS National Hurricane Center Miami FL AL082022 Issued by the NWS Weather Prediction Center College Park MD 900 PM GMT Thu Sep 22 2022 Gaston is beginning to approach the Azores Islands. An observation on Flores in the western Azores recently showed wind gusts to tropical storm strength in an outer band of the storm. Satellite images indicate that Gaston has been relatively steady in strength through the day with deep convection persisting near the center and strong outflow continuing in the northern semicircle. Since the Dvorak estimates are unchanged, the initial intensity remains 55 kt for this advisory. The storm has slowed down slightly, with the latest initial motion estimated to be east-northeastward at 15 kt. A turn to the east and an additional reduction in forward speed are expected overnight, followed by a clockwise loop near or over the central and western Azores on Friday and Saturday as the storm moves on the south side of a building ridge. The models have trended northward at days 4 and 5, and the NHC track forecast has been adjusted in that direction for those time periods. Despite moderate to strong shear, relatively dry air, and cool SSTs, Gaston has been maintaining its strength. Given that these conditions are only expected to gradually worsen for the system, a slow weakening trend seems likely. The models all show a similar theme, and the NHC intensity forecast lies near the middle of the guidance envelope. Gaston is expected to become post-tropical on Saturday when it merges with an approaching shortwave trough. Key Messages: 1. Tropical storm conditions are expected to begin later tonight in the western Azores and will likely spread to the central Azores on Friday. 2. Gaston is expected to produce heavy rainfall over the western and central Azores beginning tonight and continuing into Saturday. This rainfall may result in landslides and areas of flooding. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 41.1N 32.0W 55 KT 65 MPH 12H 23/0600Z 40.9N 30.1W 55 KT 65 MPH 24H 23/1800Z 40.1N 29.2W 55 KT 65 MPH 36H 24/0600Z 39.2N 29.5W 50 KT 60 MPH 48H 24/1800Z 38.8N 30.9W 50 KT 60 MPH...POST-TROPICAL 60H 25/0600Z 39.1N 33.1W 50 KT 60 MPH...POST-TROPICAL 72H 25/1800Z 39.3N 35.0W 45 KT 50 MPH...POST-TROPICAL 96H 26/1800Z 39.3N 37.8W 35 KT 40 MPH...POST-TROPICAL 120H 27/1800Z 40.5N 40.0W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Cangialosi/Churchill/Hamrick |
