####018002610####
WTPZ43 KNHC 240239

TCDEP3

 

Tropical Storm Otis Discussion Number   7

NWS National Hurricane Center Miami FL       EP182023

1000 PM CDT Mon Oct 23 2023



Otis has the appearance of a sheared tropical storm this evening, 

with the center on the eastern edge of a relatively new burst of 

deep convection.  The overall satellite intensity estimates still 

support an initial wind speed of 45 kt for this advisory.  Despite 

the shear, recent microwave data indicate that Otis has notable 

low-level structure, with a ring observed in 37 GHz microwave data. 

While this can be associated with rapid intensification, none of 

the models show that intensity change occurring, seemingly due to 

persistent moderate shear and some dry air in the mid-levels.  

Still, it makes sense to stay on the high side of the guidance given 

the structure and very warm SSTs in the path.  Thus, the new NHC 

forecast track is similar to the previous one, showing Otis near 

hurricane strength at landfall between 36-48 hours. 



Otis continues 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.   This flow will likely cause the storm to move to the 

north-northwest or northwest through landfall.  While most of the 

models respond by bringing Otis to the coast of southern Mexico on 

Wednesday, the GFS model remains an outlier and keeps Otis weaker 

and offshore.  The GFS solution seems very unlikely given the 

overall synoptic pattern, so the NHC track forecast will put little 

weight on its solution, keeping the official forecast about the same 

as the previous one, on the eastern side of the guidance envelope.

 

Key Messages:

 

1. Heavy rains from Otis will begin to impact areas of southwest

Mexico on Tuesday.  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

remain in effect.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  24/0300Z 13.6N  97.9W   45 KT  50 MPH

 12H  24/1200Z 14.4N  98.3W   50 KT  60 MPH

 24H  25/0000Z 15.5N  98.9W   55 KT  65 MPH

 36H  25/1200Z 16.4N  99.5W   60 KT  70 MPH

 48H  26/0000Z 17.3N 100.3W   50 KT  60 MPH...INLAND

 60H  26/1200Z 18.0N 101.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

 72H  27/0000Z...DISSIPATED

 

$$

Forecaster Blake