Tropical Cyclone Discussion

355
WTPZ42 KNHC 292037
TCDEP2
 
Tropical Storm Polo Discussion Number  37
NWS National Hurricane Center Miami FL       EP172026
200 PM MST Tue Sep 29 2026
 
Since the last advisory, Polo has moved northeastward across the 
Gulf of California and made landfall in the Mexican state of Sonora 
just east of Guaymas.  The cyclone is now weakening as it moves 
farther inland and it is estimated that it is now a 55-kt 
tropical storm. Rapid weakening is expected as Polo crosses 
northwestern Mexico, and it is likely that the surface circulation 
will dissipate tonight. A 12-h position is included in this 
advisory, but it is likely to be the position of a trough or 
vorticity maximum and not a circulation center.

The initial motion is now 040/18. Polo and its remnants are expected 
to move rapidly northeastward through Wednesday in the flow on the 
east side of a mid-latitude trough over the southwestern United 
States. This track will bring the system across northwestern Mexico 
and into portions of New Mexico and Texas as it interacts with the 
trough. This evolution will contribute to heavy rainfall, flash 
flooding, and gusty winds in the southwestern U.S. and southern 
Plains. See products issued by the Weather Prediction Center and 
local National Weather Service offices for more information.
 
 
Key Messages:
 
1. Tropical storm conditions are expected to spread across 
northwestern Mexico near the center of Polo through tonight.
 
2. Heavy rainfall associated with Polo will continue to impact the 
southern and central portions of Sonora today. This rainfall is 
expected to produce life-threatening flooding and mudslides, 
especially in areas of steep terrain. Moisture from Polo will 
support heavy rainfall and flooding potential across the Southwest 
U.S. into the Southern High Plains today into early Wednesday.
 
3. Even after the surface circulation of Polo dissipates, its low- 
to mid-level remnants may produce strong gusty winds well inland 
over the higher terrain of northwest Mexico, southern New Mexico, 
and far western Texas.
 
4. Dangerous surf and rip currents are likely to persist along 
portions of the northwest coast of Mexico and Baja California for 
the next day or so.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/2100Z 29.0N 109.7W   55 KT  65 MPH...INLAND
 12H  30/0600Z 32.6N 105.7W   30 KT  35 MPH...POST-TROP/INLAND
 24H  30/1800Z...DISSIPATED