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| #1115172 (Received by flhurricane at: 4:03 PM 07.Nov.2022) TCDAT2 Subtropical Storm Nicole Discussion Number 3 NWS National Hurricane Center Miami FL AL172022 400 PM EST Mon Nov 07 2022 Nicole`s structure has changed little today. There is some limited convective activity near the center with a large band of showers and thunderstorms extending well north and east over the southwestern Atlantic. An Air Force Reserve reconnaissance aircraft that has been investigating the system this afternoon and has found flight-level and SFMR winds supporting tropical storm strength about 80 n mi northwest of the center, but earlier scatterometer data indicated that the strongest winds are likely occurring in the band well removed from the center. The aircraft reported that the pressure is down to around 1000 mb. The initial intensity is maintained at 40 kt and is based on a blend of the aircraft and earlier satellite wind data. Nicole is moving northwestward or 310/8 kt. A northwestward motion is expected to continue overnight as the storm moves around the northeastern portion of a decaying upper-level low. On Tuesday, Nicole is forecast to turn westward or west-southwestward as a strong mid-level ridge amplifies over the eastern United States. This motion should bring the center of Nicole near or over the northwestern Bahamas on Wednesday. After that time, the ridge is forecast to shift eastward, which should allow Nicole to turn west-northwestward or northwestward as it approaches and then moves over the Florida Peninsula. Later in the period, a large mid-latitude trough moving into the central United States is expected to cause Nicole to recurve northeastward. The track guidance is in good agreement during the first few days of the forecast period, and the confidence in this portion of the track forecast is relatively high. The new NHC track foreast is similar to the previous advisory through 72 hours, but shows a track slightly farther inland along the southeast U.S. coast on day 4. There is increasing along-track spread after 72 hours, with the GFS and UKMET slower than the latest ECMWF. The NHC forecast is near the multi-model consensus aids at those times. Nicole`s sprawling structure and nearby dry mid-level air suggest that it will take some time for the cyclone to begin strengthening. Warm ocean temperatures that Nicole will be traversing should allow for a gradual increase in convection near the center, and this combined with low vertical wind shear, is expected to result in gradual moistening of the environment around Nicole. Most of the dynamical models indicate that Nicole will be able to develop a smaller inner core and transition into a tropical cyclone in 24 to 36 hours, and once that occurs, a faster rate of intensification is anticipated. The latest NHC intensity prediction is similar to the previous advisory and calls for the system to be at or near hurricane strength when it passes near or over the northwest Bahamas and reaches the east coast of Florida. The official wind speed forecast is closest to the HFIP corrected consensus, and near the most recent dynamical hurricane models. Regardless of Nicole`s exact intensity, the storm`s large size due to an enhanced pressure gradient north of the storm will likely cause significant wind, storm surge, and rainfall impacts over a large portion of the northwestern Bahamas, Florida, and the southeastern coast of the United States during the next few days. Key Messages: 1. Hurricane conditions and a dangerous storm surge are expected in portions of the northwestern Bahamas beginning Tuesday night, where a Hurricane Warning has been issued. 2. Hurricane conditions are possible across portions of the coast of southeast and east-central Florida beginning late Wednesday, where a Hurricane Watch is in effect. Tropical storm conditions are possible in the Tropical Storm Watch areas in Florida and Georgia beginning by early Wednesday. 3. A dangerous storm surge is possible across much of the east coast of Florida and portions of coastal Georgia. The storm surge will be accompanied by large and damaging waves. 4. Do not focus on the exact track of Nicole since it is expected to be a large storm with hazards extending well to the north of the center, outside of the forecast cone. These hazards are likely to affect much of the Florida peninsula and portions of the southeast U.S. 5. Nicole will produce heavy rainfall by Wednesday night and Thursday across the Florida Peninsula. Flash and urban flooding will be possible along with river rises on portions of the St. Johns River. FORECAST POSITIONS AND MAX WINDS INIT 07/2100Z 26.6N 70.6W 40 KT 45 MPH...SUBTROPICAL STORM 12H 08/0600Z 27.3N 71.5W 40 KT 45 MPH...SUBTROPICAL STORM 24H 08/1800Z 27.6N 73.2W 45 KT 50 MPH...SUBTROPICAL STORM 36H 09/0600Z 27.0N 75.5W 55 KT 65 MPH...TROPICAL CYCLONE 48H 09/1800Z 26.7N 77.6W 60 KT 70 MPH 60H 10/0600Z 27.0N 80.0W 65 KT 75 MPH 72H 10/1800Z 28.0N 82.3W 40 KT 45 MPH...INLAND 96H 11/1800Z 31.2N 82.6W 40 KT 45 MPH...INLAND 120H 12/1800Z 37.5N 73.8W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown |
