Tropical Depression Four Advisory Number 1
NWS National Hurricane Center Miami FL AL042023
500 AM AST Thu Jun 22 2023
...TROPICAL DEPRESSION FORMS IN THE CENTRAL ATLANTIC...
SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
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LOCATION...10.9N 41.1W
ABOUT 1395 MI...2240 KM E OF THE LESSER ANTILLES
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
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