Official Discussion issued by the National Hurricane Center

Twelve (AL122023) DATA RELEASED: 9/1/2023 2:00:00 PM UTC

Copy of official data

Tropical Depression Twelve Discussion Number   1
NWS National Hurricane Center Miami FL       AL122023
200 PM CVT Fri Sep 01 2023

The area of low pressure over the far eastern Atlantic to the 
northwest of the Cabo Verde Islands has developed a well-defined 
surface circulation with sufficiently organized deep convection to 
be classified as a tropical cyclone.  Dvorak classifications from 
TAFB and SAB are a consensus T2.5, but since the convection is 
loosely organized around the center, the initial intensity is 
started at 30 kt.

Sea surface temperatures of 27-28 degrees Celsius and low vertical 
shear during the next day or so should allow the depression to 
strengthen to a tropical storm later today or on Saturday.  However, 
the cyclone will be reaching marginally warm waters in 24-48 hours, 
and southerly shear is forecast to increase at about that same time. 
The NHC forecast therefore shows weakening beginning in 48 hours, 
and the system is likely to degenerate into a remnant low by 60 
hours due to a loss of organized deep convection.  The remnant low 
is shown dissipating by day 4, following the majority of the global 
model fields.

The depression is moving toward the north-northwest (340 degrees) at 
7 kt between a mid-level ridge over western Africa and a mid- to 
upper-level low located over the eastern Atlantic.  The steering 
environment changes little during the next couple of days, and the 
depression is therefore expected to move toward the north-northwest 
or northwest, at a slightly faster speed, through 48 hours.  After 
the cyclone becomes a shallower remnant low, lower-level flow is 
expected to turn the system toward the west-northwest until it 
dissipates.  The track guidance is tightly clustered for the next 4 
days, and the NHC track forecast is very close to the HCCA consensus 


INIT  01/1500Z 19.6N  28.3W   30 KT  35 MPH
12H  02/0000Z 21.0N  29.0W   35 KT  40 MPH
24H  02/1200Z 22.8N  30.2W   35 KT  40 MPH
36H  03/0000Z 24.3N  31.4W   35 KT  40 MPH
48H  03/1200Z 25.5N  32.8W   30 KT  35 MPH
60H  04/0000Z 26.0N  33.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
72H  04/1200Z 26.4N  34.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
96H  05/1200Z...DISSIPATED

Forecaster Berg