Official Discussion issued by the National Hurricane Center

Lee (AL132023) DATA RELEASED: 9/13/2023 3:00:00 PM UTC

Copy of official data

Hurricane Lee Discussion Number  33
NWS National Hurricane Center Miami FL       AL132023
1100 AM AST Wed Sep 13 2023

Lee continues to exhibit concentric eyewalls, but there are some dry 
slots between those features.  An SSMIS microwave image around 10Z 
showed that both eyewalls were open, however, recent infrared 
satellite images indicate that the inner eyewall appears to be 
becoming better organized during the past few hours.  The initial 
wind speed is held at 100 kt, but this is near the high end of the 
latest satellite intensity estimates.  The Air Force Hurricane 
Hunters are scheduled to investigate Lee this afternoon, and the 
data they collect should provide a better assessment of the 
hurricane's intensity and structure.

Satellite images suggest that Lee seems to be beginning its 
northward turn on the western side of a subtropical ridge situated 
over the central Atlantic.  The latest initial motion estimate is 
345/6 kt.  Lee should gradually increase in forward speed while 
moving northward on the west side of the ridge during the next 
couple of days, taking the core of the system to the west of Bermuda 
Thursday and Thursday night.  The combination of a shortwave trough 
and a building ridge extending into Atlantic Canada could cause Lee 
to turn slightly to the left Friday night and Saturday, which will 
likely bring Lee close to southeastern New England before it reaches 
Maine and Atlantic Canada later in the weekend.  Confidence is 
increasing in the forecast track, and the model spread is mostly 
along-track, associated with the system's forward speed/timing.  
Overall, little change was made to the previous NHC track forecast, 
and it remains very near the various consensus models.

Lee is expected to gradually weaken as it moves into an environment 
of increasing vertical wind shear, slightly drier air, and over 
progressively cooler waters during the next few days.  However, the 
large size of the system suggests that the weakening process should 
be slow.  In addition, Lee is expected to grow in size as it gains 
latitude during the next few days.  The NHC intensity forecast is 
largely the same as the previous one and fairly close to the HCCA 
and IVCN models.  Regardless of the details, there is high 
confidence that Lee will be a large hurricane near the coast of New 
England Friday night and Saturday.

It should again be noted that the 34- and 50-kt wind speed 
probabilities beyond 36 hours in the text and graphical products are 
likely underestimating the risk of those winds occurring.  This is 
because the forecast wind field of Lee is considerably larger than 
average compared to the wind field used to derive the wind speed 
probability product.


1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, the U.S East Coast, and Atlantic Canada into the weekend.

2. Tropical storm conditions, heavy rainfall, and high surf are
expected to impact Bermuda beginning early Thursday, and a Tropical 
Storm Warning is in effect for the island.

3. There is an increasing risk of wind, coastal flooding, and rain
impacts from Lee in portions of New England and Atlantic Canada
beginning on Friday and continuing through the weekend.  Watches 
will likely required for portions of these areas later today or 
tonight. Due to Lee's large size, hazards will extend well away 
from the center, and there will be little to no significance on 
exactly where the center reaches the coast.


INIT  13/1500Z 26.4N  67.2W  100 KT 115 MPH
12H  14/0000Z 27.6N  67.7W   95 KT 110 MPH
24H  14/1200Z 29.6N  68.2W   90 KT 105 MPH
36H  15/0000Z 31.8N  68.2W   85 KT 100 MPH
48H  15/1200Z 34.6N  67.6W   80 KT  90 MPH
60H  16/0000Z 37.9N  67.1W   75 KT  85 MPH
72H  16/1200Z 41.1N  67.2W   70 KT  80 MPH
96H  17/1200Z 46.1N  66.6W   50 KT  60 MPH...POST-TROP/INLAND
120H  18/1200Z 52.1N  56.4W   35 KT  40 MPH...POST-TROP/INLAND

Forecaster Cangialosi