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Tropical Depression Four Discussion Number   1
NWS National Hurricane Center Miami FL       AL042023
500 AM AST Thu Jun 22 2023
 
Satellite images and earlier satellite-derived surface winds 
indicate that the area of low pressure that NHC has been monitoring 
in the central Atlantic now has a well-defined center and 
sufficiently organized deep convection to be classified as a 
tropical depression.  The depression has a partially exposed 
low-level center with a small area of deep convection to its west. 
The initial intensity is estimated to be 30 kt based on a blend of 
subjective Dvorak classifications from TAFB and SAB.

The depression is moving just north of west or 280/9 kt.  The 
cyclone is expected to turn to the west-northwest and accelerate on 
the southern side of a mid-level ridge for the next few days.  After 
that time, the depression is forecast to turn northwestward towards 
a weakness in the ridge east of the Leeward Islands.  The model 
guidance is fairly well-clustered, and the NHC official forecast 
lies near the model consensus aids.

Environmental conditions appear conducive for gradual strengthening 
over the next few days, and the system is forecast to become a 
tropical storm in the next day or so.  Beyond 72 h, global models 
agree the vertical wind shear should increase significantly and 
weaken the cyclone.  The NHC intensity prediction starts out 
conservatively and is near lower end of the guidance envelope, most 
similar to the LGEM model.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0900Z 10.9N  41.1W   30 KT  35 MPH
 12H  22/1800Z 11.3N  42.8W   35 KT  40 MPH
 24H  23/0600Z 12.0N  45.2W   40 KT  45 MPH
 36H  23/1800Z 13.1N  47.6W   45 KT  50 MPH
 48H  24/0600Z 14.5N  50.2W   50 KT  60 MPH
 60H  24/1800Z 16.0N  52.7W   50 KT  60 MPH
 72H  25/0600Z 17.6N  55.5W   50 KT  60 MPH
 96H  26/0600Z 20.9N  60.7W   40 KT  45 MPH
120H  27/0600Z 23.3N  64.6W   30 KT  35 MPH
 
$$
Forecaster Bucci
 
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