738
WTNT42 KNHC 170835
TCDAT2

Tropical Depression Seven Discussion Number 1
NWS National Hurricane Center Miami FL AL072025
500 AM AST Wed Sep 17 2025

Satellite data indicate that Invest 92L over the central tropical
Atlantic has now developed into a tropical depression. ASCAT data
from around 00Z showed that the circulation of the system had
improved, and although it was not well defined at the time of the
pass, the system was only lacking some northerly winds on its west
side. Since deep convection has been persisting and consolidating
near the center, it appears to now meet the convective and
circulation criteria needed to be considered a tropical cyclone.
However, it should be noted that the system is quite large and there
is still considerable north-south elongation in the low-level
structure. The initial intensity is set at 30 kt based on a blend of
the ASCAT data and the latest Dvorak estimate from TAFB. The
development of this system breaks a nearly 3-week streak of no
tropical cyclones in the Atlantic basin during the peak of the
hurricane season.

The depression is well away from land and roughly midway between the
Cabo Verde Islands and the Windward Islands. The system is
estimated to be moving westward at 11 kt, but this is of low
confidence since the center has only recently formed. A turn to the
northwest, perhaps influenced by a center formation, is expected to
occur soon as the depression moves toward a weakness in the Atlantic subtropical ridge caused by a mid- to upper-level low to its north.
The models show this low weakening in a day or two, which will
likely cause the cyclone to turn back to the west-northwest late
this week. However, the system should reach the western periphery
of the ridge this weekend, resulting in a turn to the northwest or
north. The NHC track forecast is a little to the right of the
consensus aids, giving more weight to the ECMWF and Google Deep Mind predictions, which are faster and on the right side of the guidance.
Based on the steering pattern, and deterministic and ensemble model
solutions, there is high confidence that this system should pass
well east of the Windward and Leeward Islands. Interests in Bermuda
should monitor forecasts of the depression over the next several
days.

Only modest strengthening is expected over the next day or two as
the depression continues to battle moderate shear from the
aforementioned low aloft and intrusions of dry air. However, more
notable strengthening seems likely by the weekend when the system
moves into more conducive environmental conditions. The NHC
intensity forecast shows the system reaching hurricane strength
toward the end of the period, but it should be noted that the spread
in the models at that time is significant and ranges from solutions
showing a weak low to a major hurricane. This prediction is
generally in line with the IVCN aid.


FORECAST POSITIONS AND MAX WINDS

INIT 17/0900Z 13.7N 45.9W 30 KT 35 MPH
12H 17/1800Z 15.8N 47.4W 35 KT 40 MPH
24H 18/0600Z 17.6N 49.6W 40 KT 45 MPH
36H 18/1800Z 19.0N 51.9W 40 KT 45 MPH
48H 19/0600Z 19.7N 54.0W 45 KT 50 MPH
60H 19/1800Z 20.4N 55.9W 50 KT 60 MPH
72H 20/0600Z 21.6N 57.6W 55 KT 65 MPH
96H 21/0600Z 24.0N 60.0W 65 KT 75 MPH
120H 22/0600Z 26.9N 63.0W 75 KT 85 MPH

$$
Forecaster Cangialosi


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