Tropical Storm Humberto Forecast Discussion Number 4

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Issued at 1100 AM AST Thu Sep 25 2025

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WTNT43 KNHC 251438
TCDAT3
 
Tropical Storm Humberto Discussion Number   4
NWS National Hurricane Center Miami FL       AL082025
1100 AM AST Thu Sep 25 2025
 
Deep convection has been increasing near and to the east of the
center of Humberto during the past several hours, but the storm
remains asymmetric due to the effects of wind shear and dry air
entertainment.  The initial intensity is increased a little to 45
kt, which is near the high end of the latest satellite estimates.
 
The tropical storm is expected to continue to battle shear and dry 
air associated with a nearby mid- to upper-level trough for another 
day or so.  However, by the weekend, the models show the upper-level 
wind pattern becoming notably more favorable for strengthening. 
Based on the current trends and expected conducive conditions, the 
NHC intensity forecast has been nudged upward and shows Humberto 
becoming a hurricane in a day or so and then rapidly strengthening 
to a major hurricane over the weekend.  This prediction is roughly 
in line with the latest HCCA and IVCN consensus models.
 
Humberto is currently embedded in weak steering currents on the
south side of a narrow and weak subtropical high over the central
Atlantic.  This pattern should keep the storm moving slowly to the
west-northwest or northwest during the next day or two.  After that
time, Humberto is expected to become primarily steered by a much
stronger high over the western Atlantic, which should cause the
storm to speed up.  The models have trended south and west this
cycle, and the NHC track forecast has been nudged in those
directions.  This forecast keeps Humberto over the open central
and western subtropical Atlantic during the next several days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/1500Z 21.4N  56.8W   45 KT  50 MPH
 12H  26/0000Z 21.8N  57.3W   50 KT  60 MPH
 24H  26/1200Z 22.1N  57.9W   55 KT  65 MPH
 36H  27/0000Z 22.4N  58.8W   65 KT  75 MPH
 48H  27/1200Z 22.8N  60.1W   75 KT  85 MPH
 60H  28/0000Z 23.4N  61.9W   90 KT 105 MPH
 72H  28/1200Z 24.2N  64.0W  105 KT 120 MPH
 96H  29/1200Z 27.0N  67.8W  105 KT 120 MPH
120H  30/1200Z 30.7N  69.7W   95 KT 110 MPH
 
$$
Forecaster Cangialosi