|
Show Selection: |
| #1021955 (Received by flhurricane at: 4:51 PM 20.Oct.2020) TCDAT2 Tropical Storm Epsilon Discussion Number 7 NWS National Hurricane Center Miami FL AL272020 500 PM AST Tue Oct 20 2020 Epsilons structure has greatly improved this afternoon. Deep convection is wrapped more tightly around the center, and a small central dense overcast is evident in recent satellite imagery. Overall, the cyclone appears better organized and more tropical in nature as it fends off weak to moderate deep-layer shear and some dry mid-level air in its surrounding environment. There are even some hints of an eye-like feature trying to develop in recent visible and microwave imagery. A 14Z ASCAT-B overpass showed several 45-50 kt wind barbs in the northern semicircle of Epsilon, and its organization has improved since then. A T3.5 Dvorak classification from SAB supports raising the initial intensity to 55 kt with this advisory. Epsilon is a large cyclone with tropical-storm-force winds extending outward as far as 300 n mi in its northern semicircle. The cyclone has accelerated northwestward today, and its estimated motion is a somewhat uncertain 320/12 kt. Epsilon should continue to move northwestward or west-northwestward for the next several days as it is steered by a mid-level ridge to its north and east. The tightly clustered guidance envelope has shifted slightly westward and is faster with the storm motion through about 72 h, and these trends are reflected in the official NHC track forecast. Epsilon is now forecast to make its closest approach to Bermuda late Thursday night before recurving ahead of an upper-level trough that should move over the western Atlantic this weekend. By day 5, Epsilon could be near the beginning of its extratropical transition as it races northeastward across the central Atlantic. Epsilon has strengthened today despite some negative environmental factors including weak to moderate deep-layer shear and dry air noted in water vapor imagery along the southwestern periphery of the storm. Given recent satellite trends and little expected change in the environmental conditions during the next day or so, additional strengthening appears likely. The official NHC track forecast lies well above the guidance consensus in the near term and most closely follows the SHIPS output, which brings Epsilon to hurricane strength overnight. As the cyclone gains latitude and moves over waters with lower oceanic heat content beyond 48 h, the intensity is expected to level off, and the NHC forecast better aligns with the ICON and HCCA aids through the rest of the forecast period. Key Message: 1. Epsilon is forecast to be at or near hurricane strength when it makes its closest approach to Bermuda late Thursday or early Friday. While it is too soon to determine the exact details of Epsilon`s track and intensity near the island, tropical storm conditions are possible on Bermuda beginning Thursday with dangerous surf conditions also likely. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 27.9N 55.8W 55 KT 65 MPH 12H 21/0600Z 28.8N 57.8W 65 KT 75 MPH 24H 21/1800Z 29.3N 59.6W 70 KT 80 MPH 36H 22/0600Z 30.3N 60.5W 75 KT 85 MPH 48H 22/1800Z 31.6N 61.2W 75 KT 85 MPH 60H 23/0600Z 33.0N 61.6W 75 KT 85 MPH 72H 23/1800Z 34.0N 61.8W 75 KT 85 MPH 96H 24/1800Z 36.7N 60.7W 75 KT 85 MPH 120H 25/1800Z 42.0N 51.0W 70 KT 80 MPH $$ Forecaster Reinhart/Brown |