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Tropical Storm Otis Discussion Number   6
NWS National Hurricane Center Miami FL       EP182023
400 PM CDT Mon Oct 23 2023
 
The latest satellite images indicate that Otis is becoming better
organized with a curved band wrapping about halfway around the
center.  However, the low-level center is still partially exposed
due to ongoing easterly vertical wind shear.  An ASCAT-C pass from
a few hours ago showed peak winds close to 40 kt on the east side
of the system, and the 18Z Dvorak estimates have increased to 3.0/45
kt.  Based on all of that data, the initial intensity is increased
to 45 kt.
 
Otis is moving slowly north-northwestward at 6 kt in the flow
between a mid- to upper-level trough to its northwest and a ridge to
its east.  The models have trended to a faster solution with the
ECMWF, CMC, and UKMET global models bringing Otis to the coast of
southern Mexico on Wednesday.  The GFS, however, remains an outlier
and keeps Otis weaker and offshore.  The NHC track forecast leans on
the ECMWF/UKMET/CMC solutions and is a little faster than the
previous one.
 
Although Otis is expected to remain in a moderate wind shear
environment, abundant moisture and warm SSTs should support gradual
strengthening until Otis makes landfall.  The models have
trended higher, and it now appears likely that Otis will be near
hurricane strength when it reaches the coast.  Rapid weakening is
expected after Otis moves inland due to the rugged terrain in
southern and southwestern Mexico.
 
Based on the forecast, the government of Mexico has issued a
Tropical Storm Warning and Hurricane Watch for portions of southern
Mexico.
 
Key Messages:
 
1. Heavy rains from Otis will begin to impact areas of southwest
Mexico early this week.  This rainfall will produce flash and urban
flooding, along with mudslides in areas of higher terrain.
 
2. Tropical storm conditions are expected and hurricane conditions
are possible beginning late Tuesday along portions of the southern
coast of Mexico, where a Tropical Storm Warning and Hurricane Watch
are in effect.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/2100Z 13.1N  97.6W   45 KT  50 MPH
 12H  24/0600Z 13.7N  97.9W   50 KT  60 MPH
 24H  24/1800Z 14.8N  98.4W   55 KT  65 MPH
 36H  25/0600Z 15.6N  98.9W   60 KT  70 MPH
 48H  25/1800Z 16.7N  99.8W   60 KT  70 MPH
 60H  26/0600Z 17.6N 100.6W   40 KT  45 MPH...INLAND
 72H  26/1800Z 18.2N 101.1W   25 KT  30 MPH...POST-TROP/INLAND
 96H  27/1800Z...DISSIPATED
 
$$
Forecaster Cangialosi/Delgado
 
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