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Hurricane Earl Discussion Number 27
NWS National Hurricane Center Miami FL AL062022
1100 AM AST Fri Sep 09 2022
During the past six hours, Earl's satellite appearance has
oscillated between periods of gaining symmetry and becoming more
ragged, with the latter winning out right now. In fact, Earl's
previously clear eye has become partially obscured by clouds during
the last hour or two. Satellite-based intensity estimates range from
70-100 kt, but since those estimates generally haven't changed much
since the last advisory, the hurricane's intensity is held at 85 kt
for now.
Whether Earl's recent satellite degradation is another temporary
hiccup or the start of a weakening trend as it undergoes
extratropical transition over the next 24 h isn't yet clear, but
either way the intensity guidance is now in good agreement that
little or no intensification is expected going forward. Dynamical
models including the GFS and ECMWF are also in very good agreement
that Earl will become post-tropical by Saturday afternoon or
evening. This transition should coincide with the cyclone's maximum
winds to decreasing sharply while the extent of its tropical storm
or gale-force winds expands. The NHC intensity forecast shows a
slightly faster rate of weakening than the previous advisory, but is
still on the high end of the narrow intensity guidance envelope
through 72 h. The official intensity forecast is based heavily on
the consensus after that.
Earl continues to accelerate toward the northeast ahead of an
approaching shortwave trough off the New England and Atlantic Canada
coasts. This should cause Earl to accelerate further today and
tonight before it merges with the trough and slows to a relative
crawl southeast of Newfoundland as a post-tropical cyclone in about
48 h. Around day 4-5, the broader mid-latitude system should move
faster eastward, bringing extratropical Earl with it. Only minor
adjustments were made to the NHC track forecast.
KEY MESSAGES:
1. Swells generated by Earl are affecting Bermuda and the U.S. East
Coast and are expected to reach Nova Scotia and Newfoundland tonight
and on Saturday. These swells are likely to cause life-threatening
surf and rip current conditions through the weekend. Please consult
products from your local weather office.
FORECAST POSITIONS AND MAX WINDS
INIT 09/1500Z 34.2N 61.0W 85 KT 100 MPH
12H 10/0000Z 37.0N 57.9W 90 KT 105 MPH
24H 10/1200Z 41.0N 54.1W 85 KT 100 MPH
36H 11/0000Z 43.5N 52.0W 70 KT 80 MPH...POST-TROP/EXTRATROP
48H 11/1200Z 44.4N 51.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
60H 12/0000Z 45.1N 50.2W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 12/1200Z 45.5N 49.4W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 13/1200Z 45.5N 45.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 14/1200Z 46.0N 40.5W 35 KT 40 MPH...POST-TROP/EXTRATROP
$$
Forecaster D. Zelinsky
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