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Tropical Depression Norma Discussion Number  23
NWS National Hurricane Center Miami FL       EP172023
300 AM MDT Mon Oct 23 2023
 
Norma has weakened to a tropical depression as the cyclone has been 
void of deep convection since yesterday afternoon. A couple of ASCAT 
overpass between 0354 and 0441 UTC showed peak winds in the 31 to 33 
kt range, and assuming additional weakening has occurred since that 
time, the initial intensity has been lowered to 30 kt. Dry mid-level 
air has been entrained into the circulation from the northwest, and 
given the current strong shear over the system, it appears unlikely 
that significant deep convection will return.  Norma should move 
onshore the coast of western mainland Mexico later this morning, and 
it is expected to rapidly weaken and either become post-tropical or 
dissipate today over the high terrain of western Mexico.
 
Norma took a southeastward jog overnight, but it appears to have 
resumed an eastward motion at about 6 kt.  A general eastward to
motion is expected to continue until dissipation occurs.  The more 
southward initial position required a southward adjustment of the 
track forecast, but it otherwise remains near the center of the 
guidance envelope. 
 
Heavy rainfall associated flooding remains the primary threat with
this system.
 
Key Messages:
 
1. Heavy rainfall associated with Norma will diminish across 
portions of western Mexico today.  Additional isolated heavy 
rainfall may produce isolated flash flooding and mudslides in areas 
of higher terrain.
 
2. Gusty winds are possible along the coast of Sinaloa Mexico this 
morning. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/0900Z 24.5N 108.4W   30 KT  35 MPH
 12H  23/1800Z 24.7N 107.3W   25 KT  30 MPH...POST-TROP/INLAND
 24H  24/0600Z...DISSIPATED
 
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Forecaster Brown
 
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