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Tropical Storm Mario Discussion Number   5
NWS National Hurricane Center Miami FL       EP132025
300 PM CST Fri Sep 12 2025
 
Mario continues to parallel the coast of southwestern Mexico.  An 
afternoon scatterometer pass showed that Mario is still located just 
off the coast, with deep convection periodically forming near the 
low-level center and being sheared off to the west.  Peak wind 
vectors from the ASCAT pass were only 25 kt, however, the instrument 
is likely unable to resolve Mario's peak winds due to the small size 
of the storm.  The initial intensity is held at 35 kt, closest to 
the TAFB Dvorak estimate of T2.5.

Numerical models are still struggling to forecast Mario due to the 
storm's tiny circulation and proximity to the Mexican coastline.  
The European global model, Google DeepMind, and their ensembles 
generally show the system either moving inland or opening into a 
trough just offshore later today.  Of the systems that maintain 
Mario for longer into the forecast period, the intensity guidance 
envelope has trended downward this cycle.  Moderate vertical wind 
shear is expected to plague the system for the next day or so, which 
should limit any strengthening.  If Mario can survive this stage, 
the environmental conditions are forecast to briefly become more 
conducive for some gradual intensification early next week.  By the 
end of the forecast period, cool sea surface temperatures and 
increasing shear should quickly weaken and dissipate the small 
system.  Based on the latest guidance, the NHC intensity forecast 
now shows Mario becoming a post-tropical cyclone by day 4 and 
dissipating by day 5.
 
Mario continues to move west-northwestward at an estimated 12 kt, 
moving roughly parallel to the coast of Mexico.  A mid-level ridge 
to the north is expected to keep Mario on a west-northwestward 
trajectory, but at a slower forward motion, through the end of the 
forecast period.  The models that maintain Mario's circulation are 
general well clustered, and only minor adjustments were made to the 
NHC track forecast.
 
Given Mario's very close proximity to the coast of Mexico, there is 
a Tropical Storm Watch in effect for a small segment of the coast 
from Lazaro Cardenas to Punta San Telmo.
 
 
Key Messages:
1. Heavy rainfall associated with Tropical Storm Mario will impact 
Jalisco and nearby areas into Saturday morning, which could result 
in flash flooding, particularly in areas of higher terrain.
 
2. Tropical storm conditions are possible along portions of the
coast of Michoacan today while Mario moves roughly parallel to the
southwestern coast of Mexico.  Gusty winds are possible elsewhere
along the coasts of western Guerrero, Michoacan, and Colima through
tonight.  Interests in these areas should continue to monitor the
progress of Mario.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/2100Z 17.4N 102.9W   35 KT  40 MPH
 12H  13/0600Z 17.8N 104.4W   35 KT  40 MPH
 24H  13/1800Z 18.5N 106.1W   35 KT  40 MPH
 36H  14/0600Z 19.0N 107.4W   40 KT  45 MPH
 48H  14/1800Z 19.5N 109.0W   45 KT  50 MPH
 60H  15/0600Z 19.9N 110.3W   50 KT  60 MPH
 72H  15/1800Z 20.3N 111.8W   50 KT  60 MPH
 96H  16/1800Z 21.3N 114.5W   35 KT  40 MPH...POST-TROPICAL
120H  17/1800Z...DISSIPATED
 
$$
Forecaster Bucci
 
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