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Tropical Storm Norma Discussion Number  18
NWS National Hurricane Center Miami FL       EP172023
900 PM MDT Sat Oct 21 2023
 
Norma continues to move across the southern portion of the Baja 
California peninsula this evening. The satellite depiction of the 
ill-defined low-level center has been difficult to track through the 
terrain as the system has decoupled from the mid-level center. 
Infrared satellite imagery indicates that there continues to be 
bursts of convection on the northwest side. The land interaction, 
increasingly southerly shear and dry air is causing Norma to weaken. 
Subjective and objective Dvorak estimates for this advisory range 
from 55 to 60 kt. Given the current satellite depiction and the 
satellite intensity estimates, the initial intensity for this 
advisory is set to 55 kt.
 
The tropical storm is moving north-northeastward or 30 degrees at 
5 kt. The system will move across the southern portion of Baja 
California Sur through tonight. Norma should emerge over the 
southern Gulf of California early Sunday, then move northeastward to 
east-northeastward and make landfall along the coast of Sinaloa in 
western Mexico within the tropical storm warning area. The updated 
NHC track forecast is similar to the previous, and lies between 
the simple and corrected consensus aids.
 
Norma is expected to continue weakening due to the aforementioned 
vertical wind shear, drier air, and land interaction. Once Norma 
moves inland over mainland Mexico, it will quickly dissipate over 
the high terrain. The intensity forecast is similar to the 
previous advisory. The official forecast shows a 48 hour remnant 
low point for continuity, however it is possible that the system 
could be dissipated by that time.
 
 
Key Messages:
 
1. Heavy rains from Norma will continue to impact southern portions
of Baja California Sur through Sunday, and through Sinaloa into
Monday.  This rainfall will produce flash and urban flooding, along
with mudslides in areas of higher terrain.
 
2. Tropical storm conditions will continue through tonight within
the Tropical Storm Warning area over the southern Baja California
peninsula.
 
3. Norma is forecast to bring tropical storm conditions to portions 
of the west coast of mainland Mexico within the Tropical Storm 
Warning area beginning early Sunday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 23.5N 109.7W   55 KT  65 MPH
 12H  22/1200Z 24.1N 109.2W   50 KT  60 MPH...OVER WATER
 24H  23/0000Z 24.5N 108.4W   45 KT  50 MPH
 36H  23/1200Z 24.9N 107.7W   30 KT  35 MPH...INLAND
 48H  24/0000Z 25.2N 106.8W   25 KT  30 MPH...POST-TROP/INLAND
 60H  24/1200Z...DISSIPATED
 
$$
Forecaster Kelly
 
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