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WTNT45 KNHC 200852
TCDAT5

Hurricane Erin Discussion Number 36
NWS National Hurricane Center Miami FL AL052025
500 AM EDT Wed Aug 20 2025

The last center fix of an earlier Air Force Reserve Hurricane
Hunter mission found that Erin's central pressure had dropped by a
few millibars to 954 mb. Although satellite intensity estimates
have increased slightly over the past 6 hours, there is no firm
evidence to indicate that the pressure drop has translated into
stronger maximum winds, which are being held at 85 kt. A
recent AMSR2 microwave pass revealed that the hurricane has
an small inner eyewall extending about 15 n mi from the center with
a pronounced outer ring of convection extending 70-90 n mi from the
center. Another reconnaissance mission is scheduled to investigate
Erin in a few hours and should be able to help ascertain if the
winds have increased.

Erin is moving north-northwestward, or 345/11 kt, but it is likely
to turn northward very soon. The track guidance is in very good
agreement during Erin's expected recurvature over the western
Atlantic between the east coast of the U.S. and Bermuda, and no
significant changes were made to the first 24-36 hours of the
forecast. After 36 hours, there has been a notable increase in
forward speed among the models when Erin becomes embedded in the
mid-latitude westerlies, and the NHC forecast has been adjusted
accordingly. These changes are most evident at days 4 and 5, with
the new day 5 position about 600 n mi northeast of the previous day
5 forecast point.

Warm waters, relatively light shear, and upper-level divergence
could support some intensification over the next 36 hours or so.
However, it is unclear if Erin's broad structure will support much
increase of the maximum winds, despite the global models showing the
central pressure falling further into the 940s mb. The NHC
intensity forecast is closest to the HCCA consensus aid, showing
some slight strengthening through Thursday. A substantial increase
in shear is likely to induce weakening by 48 hours, and Erin is
expected to become post-tropical by day 4.

It should be noted that the 34- and 50-kt wind speed probabilities
in the text and graphical products are likely underestimating the
risk of those winds occurring. This is because the forecast wind
field of Erin is considerably larger than average compared to the
wind field used to derive the wind speed probability product.


KEY MESSAGES:

1. Erin is expected 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. Storm surge flooding and tropical storm conditions are expected
in the North Carolina Outer Banks beginning later today or tonight.
The storm surge will be accompanied by large waves, leading to
significant beach erosion and overwash, making some roads
impassible. Tropical storm conditions are possible on Thursday
along the southeastern coast of Virginia.

3. Tropical storm conditions are possible on Bermuda on Thursday and
Friday.

4. Interests elsewhere along the U.S. Mid-Atlantic and southern New
England coasts, and Atlantic Canada, should also monitor the
progress of Erin as strong winds are possible Thursday through
Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT 20/0900Z 28.9N 73.3W 85 KT 100 MPH
12H 20/1800Z 30.6N 73.5W 90 KT 105 MPH
24H 21/0600Z 33.0N 72.8W 95 KT 110 MPH
36H 21/1800Z 35.4N 70.6W 95 KT 110 MPH
48H 22/0600Z 37.4N 67.3W 90 KT 105 MPH
60H 22/1800Z 39.3N 63.1W 85 KT 100 MPH
72H 23/0600Z 41.0N 57.7W 75 KT 85 MPH
96H 24/0600Z 45.8N 43.9W 65 KT 75 MPH...POST-TROP/EXTRATROP
120H 25/0600Z 51.1N 30.8W 55 KT 65 MPH...POST-TROP/EXTRATROP

$$
Forecaster Berg


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