Advisories

000
WTPZ42 KNHC 281446
TCDEP2
 
Hurricane Polo Discussion Number  32
NWS National Hurricane Center Miami FL       EP172026
800 AM MST Mon Sep 28 2026
 
On geostationary satellite, Polo still looks pretty healthy, 
with a small central dense overcast with an embedded eye, though 
the eye feature has been coming and going. Some of this evolution 
is likely due to inner-core structural changes near the center, 
where an earlier AMSR-3 microwave pass at 0928 UTC showed evidence 
of concentric rings suggesting an eyewall replacement cycle (ERC) 
on the 37 GHz channel. The 12 UTC subjective Dvorak TAFB CI number 
remains 5.5/102 kt, though the objective intensity estimates have 
fallen some. For now, the initial intensity is being maintained at 
100 kt, pending another NOAA P-3 aircraft that should provide an 
update in the storms structure and intensity this afternoon. 

Polo appears to be making the turn to the northeast, with the 
estimated motion now at 35 degrees at 9 kt. This general heading in 
Polo's track should continue for the next 36 h, though with some 
gradual acceleration as the hurricane is captured by a short-wave 
trough swinging into the southwestern United States. This track 
will take Polo's core over the Baja California Peninsula this 
evening, then briefly moving over the Gulf of California overnight 
wit ha second landfall in northwestern mainland Mexico on Tuesday 
Morning. The latest NHC track forecast is very close to the 
previous one, following the reliable HFIP corrected consensus 
approach (HCCA) and Google DeepMind ensemble mean (GDMI).

The vertical wind shear remains low over Polo at the moment, and has 
now shifted out of the southwest, so the vector is in the same 
direction as its component of motion. In addition sea-surface 
temperatures actually warm as the hurricane approaches the 
coastline. Thus, Polo's intensity will be primarily governed by 
inner-core structural changes today before landfall. While the 
interpolated guidance shows a bit of modest weakening in 12 h, given 
the favorable environment, it is probably more prudent to maintain 
the hurricane's current intensity before it makes landfall in the 
Baja California Peninsula where it will likely be near or at major 
hurricane intensity. Land interaction with the peninsula and shear 
increasing should lead to significant weakening, but Polo is still 
expected to be a hurricane when it reaches mainland Mexico. Even 
more rapid weakening is expected when Polo moves inland over the 
high rugged terrain of northwestern mainland Mexico and the storm 
will likely dissipate over the higher terrain long before it reaches 
the southwestern U.S. 
 
Although Polo is expected to dissipate before it reaches the 
southern U.S., distant moisture associated with it and the Post- 
Tropical Cyclone Odalys will be transported into the southwestern 
United States during the next few days, and may indirectly 
contribute to a heavy rainfall and flash flood threat in the region. 
See products issued by the Weather Prediction Center for more 
information.
 
 
Key Messages:
 
1. Polo is forecast to make landfall on the west coast of the Baja 
California Peninsula near major hurricane strength this evening. 
Conditions will deteriorate shortly, making preparations difficult. 
Hurricane and tropical storm conditions are expected to spread 
across Baja California through tonight, and into mainland Mexico 
late on early Tuesday. A dangerous storm surge is likely in areas of 
onshore winds. 
 
2. Heavy rainfall from Polo will impact Baja California Sur and 
southern and central portions of Sonora today into Tuesday. This 
rainfall may 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 late today into Tuesday.
 
3. Even after Polo dissipates, its mid-level remnants may produce 
gusty winds well inland over the higher terrain of northwest
Mexico and the southwest United States. 
 
4. Dangerous surf and rip currents are likely along portions of
the northwest coast of Mexico and Baja California for the next
couple of days.
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/1500Z 24.2N 113.5W  100 KT 115 MPH
 12H  29/0000Z 25.4N 112.7W  100 KT 115 MPH
 24H  29/1200Z 27.4N 111.0W   70 KT  80 MPH...OVER WATER
 36H  30/0000Z 29.9N 108.8W   30 KT  35 MPH...POST-TROP/INLAND
 48H  30/1200Z...DISSIPATED
 
$$
Forecaster Papin