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Tropical Depression Twenty-Two Special Discussion Number   1
NWS National Hurricane Center Miami FL       AL222020
600 PM CDT Thu Sep 17 2020
 
Reports from an Air Force Reserve Hurricane Hunter aircraft indicate 
that the low pressure area over the southwestern Gulf of Mexico has 
developed a sufficiently well-defined circulation, with SFMR wind 
data suggesting an intensity of about 30 kt.  In addition, the 
associated convection is organized enough for SAB and TAFB to 
provide Dvorak satellite intensity estimates of 30 kt.  Based on 
this information, advisories are being initiated on Tropical 
Depression Twenty-Two.

The initial motion is a somewhat uncertain 035/4.  During the 
next 48 h or so, the cyclone should be steered slowly 
north-northeastward by a mid- to upper-level trough over Texas and 
northern Mexico.  After that time, the global models are in good 
agreement that this trough will weaken and lift out to the 
northeast, with a weak mid-level ridge building to the north of the 
cyclone.  This should result in a gradual turn toward the west at a 
continued slow forward speed.  Although the cyclone is relatively 
close to land, the vast majority of the track guidance keeps the 
system offshore for the next five days.  The official forecast will 
follow this scenario, with the forecast track being between the HCCA 
corrected consensus and the other consensus models.

The large-scale models suggest that the cyclone will be in an 
environment of light to moderate vertical wind shear for the next 
several days.  Some dry air entrainment may occur after 48 h.  
The bulk of the intensity guidance keeps the system below hurricane 
strength during the forecast period.  The official intensity 
forecast follows the trend of the guidance and shows the system 
peaking as a tropical storm, but it lies a little above the 
intensity consensus.

As mentioned above, the cyclone is likely to stay offshore during 
the forecast period.  Therefore, it is too early to tell which parts 
of the coast of the Gulf of Mexico will get wind, storm surge, and 
rain impacts from this system  


Key Messages: 

1.  The system is expected to strengthen to a tropical storm while 
moving slowly over the western Gulf of Mexico during the next few 
days. 

2.  While it is too early to determine what areas could see direct 
wind, storm surge, and rainfall impacts from this system, interests 
throughout the western Gulf of Mexico should monitor the progress of 
this system and future updates to the forecast. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  17/2300Z 21.9N  94.3W   30 KT  35 MPH
 12H  18/0600Z 22.7N  94.0W   30 KT  35 MPH
 24H  18/1800Z 23.8N  93.5W   35 KT  40 MPH
 36H  19/0600Z 24.8N  93.0W   45 KT  50 MPH
 48H  19/1800Z 25.4N  92.9W   55 KT  65 MPH
 60H  20/0600Z 25.8N  93.1W   60 KT  70 MPH
 72H  20/1800Z 26.1N  93.8W   60 KT  70 MPH
 96H  21/1800Z 26.1N  95.1W   55 KT  65 MPH
120H  22/1800Z 25.6N  96.1W   50 KT  60 MPH
 
$$
Forecaster Berg/Beven
 
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