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Tropical Depression Nine


WxWatcher007
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Tropical Depression Nine Discussion Number   5
NWS National Hurricane Center Miami FL       AL092025
500 PM EDT Sat Sep 27 2025
 
The organization of the depression has not changed much since this 
morning. Some deep convection has flared up this afternoon near the 
estimated center, which appears broad in the 850-mb flight-level 
wind data from the Air Force Hurricane Hunters. The earlier 
scatterometer winds and more recent aircraft data do not suggest the 
system has intensified. The initial intensity is held at 30 kt for 
this advisory.

The center appears to be slightly south and west of previous 
estimates, with an uncertain initial motion of 315/4 kt. Over the 
next couple of days, the system should turn more north-northwestward 
within the flow between an upper trough over the southeast U.S. and 
a subtropical ridge over the Atlantic. This forecast brings the 
depression over the central and northwestern Bahamas through early 
Monday, then toward the southeast U.S. coast by Tuesday. The NHC 
track forecast is very similar to the previous one, with only a 
slight nudge westward based on the initial position adjustments 
during the day. Warm waters and strong upper-level divergence should 
promote strengthening during the next few days, but this could be 
tempered by moderate southerly shear over the system from an 
upper-level trough. The NHC intensity forecast shows steady 
strengthening through early next week, with the system becoming a 
hurricane by 60 h. This prediction lies close to the latest IVCN and 
HCCA aids. 

There is still above-average uncertainty in the details of the 
long-range forecast. In general, the models agree that the presence 
of Hurricane Humberto to the east will result in a weakening of the 
prevailing steering currents, causing the system to slow down and 
meander near the southeast U.S. coast on Tuesday. While the chances 
of a landfall appear lower than yesterday, there are still some 
hurricane regional models and ensemble solutions that show this 
possibility. Given the expected asymmetric storm structure, a risk 
of significant heavy rainfall, storm surge, and wind impacts exists 
for the southeast U.S. coast even if the storm center remains 
offshore. The increased track spread at 96-120 h is related to 
whether the system feels the effects of an amplifying upper-level 
trough behind Humberto over the western Atlantic. While many global 
models show a sharp eastward turn and acceleration away from land, 
the system fails to be captured by the trough in the 12z ECMWF and 
lingers offshore. The NHC track forecast at days 4-5 maintains a 
consensus approach and shows a slower eastward motion, but future 
track adjustments are likely as confidence increases. The system may 
be in close proximity to fronts by the end of the period, so 
extratropical transition could begin around or shortly after day 5.
 
 
KEY MESSAGES:
 
1. The depression is expected to strengthen and bring tropical storm
conditions to portions of the central and northwestern Bahamas
through Sunday night. Tropical storm conditions are also possible
along portions of the east coast of central Florida beginning
Monday, where a Tropical Storm Watch is in effect.
 
2. Rainfall will continue to impact eastern Cuba, Hispaniola, 
Jamaica, and the Bahamas through the weekend, which will likely 
produce flash and urban flooding. Mudslides are possible in the 
higher terrain. 
 
3. There is a significant threat of heavy rainfall early next week 
from portions of the east coast of Florida northward into the 
Carolinas, which could cause flash, urban, and river flooding. 
 
4. The depression is expected to be at or near hurricane intensity 
when it is closest to the southeast U.S. coast early next week, 
where there is a risk of storm surge and wind impacts. Although it 
is too soon to specify the exact location and magnitude of impacts, 
residents should closely monitor the latest forecast updates and 
ensure that they have their hurricane plan in place.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/2100Z 22.2N  76.5W   30 KT  35 MPH
 12H  28/0600Z 23.3N  77.1W   35 KT  40 MPH
 24H  28/1800Z 24.9N  77.6W   45 KT  50 MPH
 36H  29/0600Z 26.7N  78.1W   55 KT  65 MPH
 48H  29/1800Z 28.5N  78.6W   60 KT  70 MPH
 60H  30/0600Z 30.0N  78.8W   65 KT  75 MPH
 72H  30/1800Z 30.8N  78.6W   65 KT  75 MPH
 96H  01/1800Z 31.1N  76.8W   65 KT  75 MPH
120H  02/1800Z 31.5N  74.0W   60 KT  70 MPH
 
$$
Forecaster Reinhart
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