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| #1115138 (Received by flhurricane at: 10:09 AM 07.Nov.2022) TCDAT2 Subtropical Storm Nicole Discussion Number 2 NWS National Hurricane Center Miami FL AL172022 1100 AM AST Mon Nov 07 2022 The structure of Nicole this morning remains distinctly subtropical, as the low-level circulation remains tangled up with an elongated upper-level low. The wind-field also remains quite broad, with data from the NOAA-P3 Hurricane Hunters this morning showing the highest winds remaining displaced well away from the center. The initial intensity is being held at 40 kt for this advisory which is supported by the subtropical classification of ST2.5/35-40 kt from TAFB, the earlier scatterometer data, and recent SFMR winds from the NOAA-P3 aircraft in the 40-kt range. Nicole might be starting to take a northwestward turn this morning, with the estimated motion at 320/8 kt. A continued northwestward motion is expected through the day, though there might be some wobbles more north or west here and there as the low-level circulation continues to interact with the decaying upper-level low. After 24 hours, an anomalously strong mid-level ridge is expected to amplify over the southeastern U.S. which is expected to steer Nicole and result in the system turning westward or even west-southwestward on Tuesday night into Wednesday. This ridging will then re-position itself to the northeast of Nicole by Thursday and Friday which is expected to allow the cyclone to begin gaining latitude after it moves across the Florida Peninsula, though how quickly this occurs is a source of track uncertainty in this time frame. Finally a broad mid-latitude trough is forecast to eject out of the Rockies into the Great Lakes region, further eroding the ridge and allowing Nicole to recurve by the end of the forecast period. The track guidance is fairly tightly clustered for the first 60 hours of the forecast, though it has taken a noticeable shift southward this cycle, and the NHC track forecast was shifted a bit southward due to this adjustment, but still is a bit north of the HFIP Corrected Consensus Approach (HCCA). Intensity wise, Nicole may take some time to consolidate given its large radius of maximum winds and currently meager central convection due to nearby dry air related to the nearby upper-level low. This feature should gradually decay and warm 27-28 C sea-surface temperatures should enable more organized convection to develop while the system remains in a low vertical wind shear environment. Nicole is forecast to transition to a tropical storm sometime in the 24-36 hour period as this convection helps to contract the radius of maximum wind, with further intensification expected thereafter. The intensity guidance was a bit higher this cycle, and the latest forecast now takes Nicole to a 65-kt hurricane in 60 hours, which is close to the latest HCCA, HMON, and SHIPS guidance. After Nicole moves inland, weakening is anticipated, and the region that Nicole is forecast to emerge off in the northern Gulf of Mexico has cooler SSTs that likely would not support robust reintensification. Regardless on the ultimate intensity of Nicole, 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 much of the upcoming week. Key Messages: 1. Hurricane conditions are possible across portions of the northwestern Bahamas and southeast to east-central Florida beginning Wednesday, where a Hurricane Watch has been issued. Tropical storm conditions are possible in the Tropical Storm Watch areas in Florida and Georgia beginning Wednesday. 2. A dangerous storm surge is possible across portions of the northwestern Bahamas, much of the east coast of Florida and portions of coastal Georgia. A Storm Surge Watch has been issued for most of the east coast of Florida and portions of coastal Georgia. 3. 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, and outside of the cone, and affect much of the Florida peninsula and portions of the southeast U.S. 4. Nicole will produce heavy rainfall by Wednesday night and Thursday across the Florida Peninsula. Flash and urban flooding will be possible across portions of the Florida Peninsula along with river rises on portions of the St. Johns River. FORECAST POSITIONS AND MAX WINDS INIT 07/1500Z 26.2N 69.4W 40 KT 45 MPH...SUBTROPICAL STORM 12H 08/0000Z 27.0N 70.5W 40 KT 45 MPH...SUBTROPICAL STORM 24H 08/1200Z 27.7N 71.9W 45 KT 50 MPH...SUBTROPICAL STORM 36H 09/0000Z 27.6N 74.1W 55 KT 65 MPH...TROPICAL STORM 48H 09/1200Z 26.9N 76.5W 60 KT 70 MPH 60H 10/0000Z 26.6N 78.7W 65 KT 75 MPH 72H 10/1200Z 27.3N 81.2W 50 KT 60 MPH 96H 11/1200Z 29.4N 83.9W 45 KT 50 MPH 120H 12/1200Z 33.3N 79.0W 45 KT 50 MPH...INLAND $$ Forecaster Papin/Brown |
