Official Discussion issued by the National Hurricane Center

Epsilon (AL272020) DATA RELEASED: 10/23/2020 9:00:00 AM UTC

Copy of official data

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