Tropical Depression Nine Forecast Discussion Number 2

By | August 21, 2023

000
WTNT44 KNHC 212045
TCDAT4

Tropical Depression Nine Discussion Number   2
NWS National Hurricane Center Miami FL       AL092023
400 PM CDT Mon Aug 21 2023

An ASCAT pass from a few hours ago and data from the Air Force
Hurricane Hunters indicate that the system now has a closed and 
fairly well-defined center of circulation.  In addition, deep 
convection has been persisting over the central and western Gulf of 
Mexico.  The system now meets the definition of a tropical 
depression, and the initial intensity is estimated to be 30 kt.  The
far outer bands of the depression are nearing the coast of Texas and
northern Mexico, and they are expected to begin moving inland
tonight.

The depression is moving fairly quickly to the west at 16 kt on the
south side of a strong mid-level ridge located over the central 
United States.  A continued quick west or west-northwest motion is 
expected, taking the system over southern Texas by midday Tuesday.  
The models are in fairly good agreement, and little change was made 
to the previous NHC track forecast.

Strengthening is expected, but the limited time over water and its
current broad structure suggest that rapid intensification is
unlikely.  The system is expected to move inland between the 12- and
24-hour points so it is possible that the system gets a little
stronger than the forecast intensity values.

KEY MESSAGES:

1. Heavy rainfall from the depression is expected across South 
Texas on Tuesday and Wednesday, and may produce areas of flash and 
urban flooding. Across portions of northern Coahuila and northern 
Nuevo Leon in Mexico, flash flooding with possible landslides in 
mountainous terrain is expected Tuesday into Wednesday.

2. Coastal flooding is possible along the south Texas coast
tonight through Tuesday morning.

3. Tropical storm conditions are expected in the warning area and
are possible in the watch area beginning early Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 25.2N  91.6W   30 KT  35 MPH
 12H  22/0600Z 25.8N  94.9W   40 KT  45 MPH
 24H  22/1800Z 26.8N  98.4W   40 KT  45 MPH...INLAND
 36H  23/0600Z 28.1N 101.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  23/1800Z...DISSIPATED

$$
Forecaster Cangialosi

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