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Tropical Storm Odalys Discussion Number   1
NWS National Hurricane Center Miami FL       EP202020
200 PM PDT Tue Nov 03 2020
 
The low pressure area well south-southwest of the southern tip of
the Baja California Peninsula has become significantly better
organized today. A curved band of deep convection is noted to the
northwest of the low-level center, and a second weaker band is
located to its southeast. Satellite-derived wind data indicate the
low-level center is still somewhat broad, but it appears to have
enough definition to justify starting advisories as a tropical
cyclone. Recent ASCAT-B data show numerous 30+ kt wind barbs, with
a couple barbs peaking at 33-34 kt in the eastern semicircle of the
cyclone. Considering known under-sampling issues with this data
source, the initial intensity is set at 35 kt, which is consistent
with a T2.5 subjective Dvorak classification from TAFB. Thus, the
system has become a tropical storm, and advisories are initiated on
Tropical Storm Odalys.
 
Weak to moderate vertical wind shear and sufficient oceanic heat
content may support modest strengthening during the next 12 h or so.
By 24-36 h, strong southwesterly deep-layer shear associated with an
approaching shortwave trough to the northwest, along with intrusions
of drier mid-level air, will induce a steady and perhaps rapid
weakening trend. The system is forecast to weaken to a depression by
48 h and a remnant low by 96 h, but this could occur even sooner if
the stronger shear values noted in the SHIPS guidance are realized.
The GFS simulated satellite imagery suggests the system could be
devoid of deep convection as early as day 3 of the forecast period.
 
The storm’s estimated motion is a somewhat uncertain 295/11 kt. A
slight increase in forward speed is expected during the next couple
of days as Odalys is steered northwestward by a low- to mid-level
ridge centered over southern Texas and northern Mexico. Then, the
cyclone should gradually slow down and turn westward as this ridge
weakens due to the aforementioned shortwave trough. By 72 h, the
storm will be steered southwestward by another low- to mid-level
ridge building to its northwest. The track models are in decent
agreement, and the official NHC track forecast lies near the center
of the guidance envelope closest to the track consensus aids.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/2100Z 14.1N 116.1W   35 KT  40 MPH
 12H  04/0600Z 15.2N 117.9W   40 KT  45 MPH
 24H  04/1800Z 16.8N 120.1W   40 KT  45 MPH
 36H  05/0600Z 17.9N 122.0W   35 KT  40 MPH
 48H  05/1800Z 18.5N 123.7W   30 KT  35 MPH
 60H  06/0600Z 18.5N 125.4W   25 KT  30 MPH
 72H  06/1800Z 18.0N 126.5W   25 KT  30 MPH
 96H  07/1800Z 16.0N 128.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  08/1800Z...DISSIPATED
 
$$
Forecaster Reinhart/Beven
 
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