Tropical Cyclone Discussion

411
WTPZ42 KNHC 291444
TCDEP2
 
Hurricane Polo Discussion Number  36
NWS National Hurricane Center Miami FL       EP172026
800 AM MST Tue Sep 29 2026

Polo is now over the Gulf of California, with convection increasing 
near the center. The cyclone weakened during its passage over Baja 
California del Sur, but the consensus of the satellite intensity 
estimates is that it remains a hurricane with winds near 65 kt.

The initial motion is now 040/15. Polo is expected to accelerate 
northeastward in the flow on the east side of a mid-latitude trough 
over the southwestern United States.  The forecast track shows the 
cyclone making landfall near Guaymas in the next few hours and then 
crossing northwestern Mexico until dissipation occurs.

Little change in strength is likely before landfall. After landfall 
the surface circulation should weaken rapidly over the rough terrain 
of northwestern Mexico, with the circulation dissipating between 
12-24 h. However, Polo's remnant vorticity will continue moving 
northeastward and likely interact and phase with aforementioned 
mid-latitude trough digging into the Four Corners region of the U.S. 
on Tuesday night and Wednesday.  This 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. Hurricane conditions are expected in southern Sonora as the 
center of Polo moves inland, and residents there should remain in a 
safe shelter through this morning. Hurricane and tropical storm 
conditions will spread across northwestern Mexico near the center 
of Polo through this afternoon. A dangerous storm surge is expected 
at the coast in areas of onshore winds.
 
2. Heavy rainfall associated with Polo will 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 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 along portions of the
northwest coast of Mexico and Baja California for the next day or
so.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/1500Z 27.8N 110.9W   65 KT  75 MPH
 12H  30/0000Z 30.5N 108.2W   40 KT  45 MPH...POST-TROP/INLAND
 24H  30/1200Z...DISSIPATED