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Hurricane Humberto Discussion Number  17
NWS National Hurricane Center Miami FL       AL082025
500 PM AST Sun Sep 28 2025

Humberto continues to have a small inner core, surrounded by a much 
larger ring of deep convection. This structure is evident in visible 
and IR satellite imagery, in which a moat of warmer cloud tops 
outside of the inner eyewall has been noted at times during day. 
This structure has likely caused Humberto's intensity to decrease 
today, and the 125-kt intensity estimate is on the high end of 
recent objective and subjective estimates. However, this has also 
caused the wind field to increase, which was confirmed by ASCAT data 
that arrived shortly after the issuance of the previous advisory. An 
Air Force Reserve Hurricane Hunter aircraft is scheduled to 
investigate Humberto this evening, which should provide more 
information about the strength and structure of the hurricane.

Overall, no significant changes were made to the NHC track, 
intensity, or radii forecasts for Humberto. The hurricane should 
move west and then north of Bermuda over the next few days while it 
slowly weakens but grows in size. Confidence in the forecast through 
that period is fairly high, with the model spread being smaller than 
normal. The forecast uncertainty is higher after that, but Humberto 
is subsequently expected to become a post-tropical frontal low 
between 72 and 96 h. Regardless of its exact strength or forward 
speed, Humberto will be a strong and large hurricane-strength low 
throughout the forecast period, even as its surface circulation will 
likely become ill defined by the end of the week. The NHC forecast 
is close to a blend of the multi-model consensus and the Google 
DeepMind Ensemble Mean at all times.

The primary concerns for Humberto continue to be its production of 
dangerous surf which will affect Bermuda and the U.S. East Coast 
for the next several days, and the growth of its wind field, which 
could result in tropical-storm-force winds affecting Bermuda 
by late Tuesday.
 
KEY MESSAGES:
 
1. Tropical-storm-force winds could begin to affect Bermuda by late 
Tuesday. The Bermuda Weather Service has issued a Tropical Storm 
Watch for Bermuda. Interests there should continue to monitor the 
progress of Humberto.
 
2. Dangerous marine conditions, including high surf and
life-threatening rip currents, are affecting beaches of the northern
Caribbean, Bahamas, and Bermuda. The dangerous surf conditions are
expected to begin affecting the U.S. East Coast on Monday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/2100Z 25.5N  65.4W  125 KT 145 MPH
 12H  29/0600Z 26.8N  66.6W  120 KT 140 MPH
 24H  29/1800Z 28.7N  67.9W  115 KT 130 MPH
 36H  30/0600Z 30.8N  68.8W  105 KT 120 MPH
 48H  30/1800Z 33.3N  68.7W   95 KT 110 MPH
 60H  01/0600Z 35.2N  67.1W   90 KT 105 MPH
 72H  01/1800Z 36.4N  62.9W   85 KT 100 MPH
 96H  02/1800Z 41.5N  47.0W   80 KT  90 MPH...POST-TROP/EXTRATROP
120H  03/1800Z...DISSIPATED
 
$$
Forecaster D. Zelinsky
 
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