932
WTNT45 KNHC 220843
TCDAT5

Hurricane Erin Discussion Number 44
NWS National Hurricane Center Miami FL AL052025
500 AM AST Fri Aug 22 2025

Erin has begun extratropical transition. The center is now exposed
to the southwest of the remaining central deep convection due to
30-35 kt of southwesterly shear. In addition, the hurricane has
developed an expansive cirrus shield to the north, and stratus and stratocumulus clouds off the Mid-Atlantic U.S. coast suggest that
cold air advection is occuring in the hurricane's wake. Based on
the degradation of the satellite presentation since the previous
full advisory, the initial intensity is lowered to 80 kt. The wind
field continues to grow, and tropical-storm-force winds now extend
as far as 320 n mi from the center.

The hurricane has been moving northeastward, or 055/19 kt. Erin
will accelerate toward the east-northeast, embedded within the
mid-latitude westerlies, reaching a peak speed of about 35 kt in 48
hours. A significant reduction in forward speed is then expected
on days 3 through 5 as the cyclone becomes cut off from the
westerlies, stalling or meandering just south of Iceland by the
middle of next week. The NHC track forecast is close to a blend of
the GFS, ECMWF, and HCCA models, and no significant changes were
made from the previous forecast.

Global model thermal fields, model-simulated satellite imagery, and
phase-space diagrams indicate that Erin should become post-tropical
by 24 hours. The NHC intensity forecast generally follows a blend
of the GFS and ECMWF surface wind fields, showing only some
weakening during the next 36-48 hours. Global models are in good
agreement that the post-tropical cyclone will phase with an
upper-level trough in 48-60 hours, inducing baroclinic
reintensification and possibly the development of a sting jet on
the back side of the low. The NHC official forecast shows that
strengthening at 60 hours. Steady weakening, and even more
broadening of the wind field, should occur on days 3 through 5 as
the low becomes vertically stacked south of Iceland.


KEY MESSAGES:

1. Erin will continue to produce life-threatening surf and rip
currents along the beaches of the Bahamas, much of the east coast of
the U.S., Bermuda, and Atlantic Canada during the next several days.
Beachgoers in those areas should follow advice from lifeguards,
local authorities, and beach warning flags.

2. Coastal flooding is expected at times of high tide along portions
of the U.S. Mid-Atlantic and New England coasts through tonight,
making some roads impassable. Large waves along the coast could
also cause significant beach erosion and overwash.

3. Gusts to gale force are possible along the coast of Nova Scotia
today and the Avalon Peninsula of Newfoundland on Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT 22/0900Z 38.6N 65.3W 80 KT 90 MPH
12H 22/1800Z 39.9N 61.6W 80 KT 90 MPH
24H 23/0600Z 41.8N 55.2W 75 KT 85 MPH...POST-TROP/EXTRATROP
36H 23/1800Z 44.1N 47.3W 70 KT 80 MPH...POST-TROP/EXTRATROP
48H 24/0600Z 47.4N 38.4W 70 KT 80 MPH...POST-TROP/EXTRATROP
60H 24/1800Z 50.8N 30.6W 75 KT 85 MPH...POST-TROP/EXTRATROP
72H 25/0600Z 53.9N 24.8W 65 KT 75 MPH...POST-TROP/EXTRATROP
96H 26/0600Z 58.0N 20.9W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 27/0600Z 58.2N 20.1W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Berg


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