Tropical Depression Seven Discussion Number   5
NWS National Hurricane Center Miami FL       AL072024
Issued by the NWS Weather Prediction Center College Park MD
1100 AM AST Thu Sep 12 2024

Tropical Depression Seven looks more organized on satellite imagery 
this morning, with a compact circulation and a small curved band 
with some deep convection. Subjective and objective Dvorak numbers 
indicate the system is close to becoming a tropical storm. However,
given the relatively small size of ongoing convection near the 
center, the initial intensity was conservatively held at 30 knots, 
or at the lower end of the estimates.

The cyclone continues on a west-northwestward heading, and the 
general motion is expected to continue over the next 2-3 days. The 
forward speed should gradually slow as the subtropical ridge to the 
north of the system weakens. Track guidance diverges considerably 
early next week, related to uncertainties with an amplifying trough 
over the north-central Atlantic Ocean and another ridge centered 
northeast of the Leeward Islands. This track forecast stays close 
to the global model consensus and places less weight on the 
regional hurricane models which depict a considerably weaker 
and less organized system. This produces a track forecast that is 
slightly faster and to the left of the previous forecast.

While environmental conditions are somewhat favorable for gradual 
strengthening, with low-moderate vertical wind shear and 
marginally warm SSTs, intensity guidance came in lower for this 
cycle. We show the system becoming a tropical storm in the next 
day, followed by the intensity only slowly increasing to 45 knots in 
the next five days. However, there is potential for greater 
strengthening beyond what is shown early next week as the cyclone 
will be in an environment characterized by lower shear, warmer SSTs 
around 28C, slightly more instability, but plentiful dry air aloft. 
The new forecast is a little lower than the previous one, but 
above the latest model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 17.8N  34.6W   30 KT  35 MPH
12H  13/0000Z 18.5N  36.4W   35 KT  40 MPH
24H  13/1200Z 19.2N  38.6W   35 KT  40 MPH
36H  14/0000Z 19.6N  40.5W   40 KT  45 MPH
48H  14/1200Z 19.7N  42.1W   40 KT  45 MPH
60H  15/0000Z 19.8N  43.6W   40 KT  45 MPH
72H  15/1200Z 20.1N  44.9W   40 KT  45 MPH
96H  16/1200Z 20.6N  46.7W   40 KT  45 MPH
120H  17/1200Z 21.0N  47.8W   45 KT  50 MPH

$$
Forecaster Lamers/Bann/Blake