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Tropical Storm Otis Discussion Number   9
NWS National Hurricane Center Miami FL       EP182023
1000 AM CDT Tue Oct 24 2023
 
Satellite imagery indicates that Otis continues to become better
organized.  There is very cold-topped convection with the Central
Dense Overcast surrounded by a number of convective banding
features.  Upper-level outflow is well-defined over most of the
circulation.  Subjective Dvorak intensity estimates range from
55 to 65 kt and the current intensity estimate is set at 60 kt
for this advisory.  An Air Force Reserve Unit Hurricane Hunter
aircraft is scheduled to investigate Otis this afternoon, which
should provide a good estimate of the intensity of the tropical
cyclone.
 
Sea surface temperatures are very warm, around 30 deg C, and the
low-to mid-level humidities are fairly high.  There is weak to
moderate south-southeasterly shear over the system, which is
located on the western periphery of an upper-tropospheric
anticyclone.  Steady strengthening seems likely until Otis makes
landfall within the next day or so.  Based on the current
trends, the official intensity forecast is above most of the model
guidance.  The SHIPS Rapid Intensification (RI) indices show a
greater than normal probability of RI, so some further upward
adjustments to the intensity forecast are possible later today.
Otis should rapidly weaken over the mountains of Mexico after it
moves inland.
 
Otis continues on its north-northwestward track and the initial
motion estimate is 330/7 kt.  A mostly north-northwestward
motion is expected to continue during the next couple of days while
the tropical cyclone moves between a mid- to upper-level trough to
the cyclone's northwest and a ridge to its east.  On this track,
the center should cross the coastline of southern Mexico in a day
or so.  The interaction of the circulation of Otis with the
mountainous terrain of Mexico could induce a slight leftward turn
as the system nears the coastline.  The official track forecast is
fairly close to the previous NHC prediction and on the left side of
the model guidance suite.
 
Key Messages:
 
1. Otis is forecast to become a hurricane before it reaches the
southern coast of Mexico late tonight or Wednesday, and hurricane
and tropical storm conditions are expected along portions of the
southern coast of Mexico where hurricane and tropical storm
warnings are in effect.
 
2. 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.
 
3. A dangerous storm surge is expected to produce significant
coastal flooding near and to the east of where the center makes
landfall.  Near the coast, the surge will be accompanied by large
and destructive waves.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 14.8N  99.1W   60 KT  70 MPH
 12H  25/0000Z 15.6N  99.5W   70 KT  80 MPH
 24H  25/1200Z 16.6N 100.1W   80 KT  90 MPH
 36H  26/0000Z 17.2N 100.6W   70 KT  80 MPH...INLAND
 48H  26/1200Z 17.9N 101.3W   45 KT  50 MPH...INLAND
 60H  27/0000Z 18.3N 102.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  27/1200Z...DISSIPATED
 
$$
Forecaster Pasch
 
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