703 
WTNT45 KNHC 210846
TCDAT5
 
Hurricane Erin Discussion Number  40
NWS National Hurricane Center Miami FL       AL052025
500 AM EDT Thu Aug 21 2025
 
Erin's satellite presentation currently shows the low-level center 
embedded beneath a 90 n mi-wide Central Dense Overcast.  Outer 
convective bands extend a couple of hundred miles away from the 
center, but there has recently been some erosion of the clouds 
within the southwestern part of the circulation, which likely 
signals an increase in shear.  On the last transect through the 
storm, the Air Force Reserve Hurricane Hunters measured 700-mb 
flight-level winds of 100 kt, and found that the central pressure 
had risen to 945 mb.  The current intensity is estimated to be 90 
kt, although it should be noted that some of the satellite intensity 
estimates are lower.
 
Erin has made its closest approach to the North Carolina coast and 
is now moving north-northeastward (020 degrees) at 15 kt.  There is 
no change in the forecast reasoning of the future track.  Erin 
should continue to accelerate and turn east-northeastward by Friday 
as it becomes increasingly embedded within the mid-latitude 
westerlies.  The new NHC track forecast is a bit faster than the 
previous prediction, showing Erin racing across the north Atlantic 
with a peak forward speed of about 35 kt in 72 hours.
 
The prospects for strengthening appear to be coming to a close, 
particularly with the atmosphere becoming more stable and shear 
increasing during the next 12-24 hours.  Only slow weakening is 
forecast during the next 36 hours, but steady weakening is likely 
after that time.  Erin's transition to a post-tropical cyclone has 
been moved up to 60 hours in the official forecast, but some of the 
latest guidance indicate it could happen as soon as 36-48 hours 
from now.  The global models, including the GFS and ECMWF, are also 
trending toward keeping the post-tropical cyclone big and strong 
while it moves across the north Atlantic, and the NHC wind radii and 
intensity forecasts have been adjusted upward accordingly.

 
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. Storm surge flooding and tropical storm conditions will continue
on the North Carolina Outer Banks today.  The storm surge will be 
accompanied by large waves, leading to significant beach erosion and 
overwash, making some roads impassible.
 
3. Tropical storm conditions are expected today along the Virginia 
coast.  Wind gusts to tropical storm force are likely along
portions of the remainder of the U.S. Mid-Atlantic and southern New
England coasts today through early Friday.
 
4. Tropical storm conditions are possible on Bermuda this afternoon 
through early Friday.  Gusts to gale force are possible along the 
coast of Nova Scotia on Friday and the Avalon Peninsula of 
Newfoundland on Saturday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0900Z 34.2N  72.1W   90 KT 105 MPH
 12H  21/1800Z 35.8N  70.3W   90 KT 105 MPH
 24H  22/0600Z 37.8N  66.7W   85 KT 100 MPH
 36H  22/1800Z 39.6N  62.1W   85 KT 100 MPH
 48H  23/0600Z 41.4N  56.2W   75 KT  85 MPH
 60H  23/1800Z 43.6N  48.7W   65 KT  75 MPH...POST-TROP/EXTRATROP
 72H  24/0600Z 46.7N  40.2W   60 KT  70 MPH...POST-TROP/EXTRATROP
 96H  25/0600Z 53.0N  26.7W   55 KT  65 MPH...POST-TROP/EXTRATROP
120H  26/0600Z 56.8N  21.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Berg