|
Show Selection: |
| #1108571 (Received by flhurricane at: 4:45 PM 23.Sep.2022) TCDAT3 Tropical Storm Gaston Discussion Number 14 NWS National Hurricane Center Miami FL AL082022 900 PM GMT Fri Sep 23 2022 Convection has been sputtering in recent hours in the core of Gaston. It appears the effects of strong vertical wind shear, dry middle-level humidities and cool sea surface temperatures have weakened the storm. Satellite Dvorak estimates from both TAFB and SAB suggest the storm is now 45 kt while and earlier scatterometer pass showed a decent area of 50-55 kt winds. The initial intensity has been lowered to 50 kt to represent a blend of these estimates. Gaston is moving southward at about 8 kt toward the central Azores. A building mid-tropospheric ridge to the north is expected to turn the storm towards the southwest early tomorrow. The ridge will eventually steer Gaston westward in about a day or so, and this motion is forecast to continue until the end of the period. The official forecast track is very similar to the previous advisory prediction except being slightly farther east in the first 12 hours due to the present location and motion. The tropical nature of Gaston seems to be winding down quickly. Simulated satellite imagery from global models suggests the storm will become fully post-tropical in about 36 hours. Statistical model guidance insists that, despite strong to moderate vertical wind shear and dry air, Gaston should only gradually weaken. The NHC intensity forecast reflects this and is close the multi-model consensus guidance and slightly lower than the previous forecast. However, it is entirely possible Gaston could weaken more rapidly than expected. Key Messages: 1. Tropical storm conditions are expected over portions of the western and central Azores. 2. Gaston is expected to produce heavy rainfall over the western and central Azores Friday into Saturday. This rainfall may result in landslides and areas of flooding. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 39.6N 28.7W 50 KT 60 MPH 12H 24/0600Z 38.8N 29.1W 50 KT 60 MPH 24H 24/1800Z 38.5N 30.8W 50 KT 60 MPH 36H 25/0600Z 38.7N 33.2W 45 KT 50 MPH...POST-TROPICAL 48H 25/1800Z 38.9N 35.4W 45 KT 50 MPH...POST-TROPICAL 60H 26/0600Z 38.9N 37.3W 45 KT 50 MPH...POST-TROPICAL 72H 26/1800Z 38.9N 39.1W 40 KT 45 MPH...POST-TROPICAL 96H 27/1800Z 38.5N 43.1W 35 KT 40 MPH...POST-TROPICAL 120H 28/1800Z...DISSIPATED $$ Forecaster Bucci |
