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Hurricane Epsilon Forecast Discussion Number 18
2020-10-23 10:39:03| National Hurricane Center (Atlantic)
Issued at 500 AM AST Fri Oct 23 2020 000 WTNT42 KNHC 230838 TCDAT2 Hurricane Epsilon Discussion Number 18 NWS National Hurricane Center Miami FL AL272020 500 AM AST Fri Oct 23 2020 Although Epsilon is moving over 25.5 deg C sea-surface temperatures (SST), the hurricane has continued to generate deep convection around the small 15-nmi-wide eye. Upper-level outflow also remains impressive in all quadrants, but especially in the northern semicircle where a pronounced poleward outflow channel has become established. The initial intensity remains at 75 kt based on a Dvorak classifications from TAFB and SAB yielding a Current Intensity (CI) number of T4.5/77 kt. The 34-kt and 50-kt wind radii were expanded based on recent ASCAT scatterometer wind data between 0100-0300 UTC. Epsilon is now moving northward, or 360/07 kt. The hurricane is forecast to continue moving northward today around the western periphery of a deep-layer subtropical ridge located east of the cyclone. On Saturday, Epsilon is expected to turn northeastward and accelerate ahead of an approaching shortwave trough and associated frontal system that will be moving off the U.S. east coast on Sunday. That motion will take Epsilon over increasingly cooler SSTs as low as 20 deg C by Sunday morning, resulting in extratropical transition by 60 h, if not sooner. The new NHC official track forecast is very similar to the previous advisory track, and lies close to the middle of the tightly packed simple- and corrected- consensus models. The current relatively low southerly vertical wind shear of about 10 kt is forecast to gradually increase to more than 20 kt by this evening. Although Epsilon will be moving over a modestly warm oceanic eddy today, which could result in some brief restrengthening of the cyclone, the official intensity forecast calls for the intensity to remain steady for the next 36 h, followed by slow weakening thereafter due to the hurricane moving over near-20 deg C SSTs by 48 hours. By 60 hours, the global models and the GFS- and ECMWF-based SHIPS guidance indicate that Epsilon will have undergone extratropical transition over the far north Atlantic. Afterward, the global models continue to show Epsilon getting absorbed by a larger extratropical cyclone at the higher latitudes, resulting in a very powerful low developing with a central pressure near 940 mb. That low then moves eastward, possibly menacing northern Europe by the middle of next week. The forecast wind radii, which show the cyclone expanding over the next few days, are in good agreement with the dynamical consensus radii guidance, RVCN. Key Messages: 1. Dangerous and potentially life-threatening surf and rip currents are expected along the coasts of Bermuda, the Bahamas, the Greater Antilles, the Leeward Islands, the east coast of the United States, and Atlantic Canada during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 33.1N 61.6W 75 KT 85 MPH 12H 23/1800Z 34.7N 61.5W 75 KT 85 MPH 24H 24/0600Z 36.7N 61.2W 75 KT 85 MPH 36H 24/1800Z 38.8N 58.9W 75 KT 85 MPH 48H 25/0600Z 42.0N 54.0W 70 KT 80 MPH 60H 25/1800Z 46.0N 45.7W 65 KT 75 MPH...POST-TROP/EXTRATROP 72H 26/0600Z 49.9N 34.8W 60 KT 70 MPH...POST-TROP/EXTRATROP 96H 27/0600Z...ABSORBED BY LARGER EXTRATROPICAL LOW $$ Forecaster Stewart
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