Hurricane Polo

174 
WTPZ42 KNHC 220247
TCDEP2
 
Hurricane Polo Discussion Number   6
NWS National Hurricane Center Miami FL       EP172026
900 PM CST Mon Sep 21 2026
 
Polo continues to rapidly intensify (RI) this evening. On 
geostationary satellite, the hurricane's structure is becoming 
increasingly impressive, with the earlier ragged eye clearing out as 
very cold cloud tops (-80 C and below) wrap around. In addition, an 
F17 SSMIS microwave pass at 0105 UTC suggests the earlier eyewall 
replacement cycle (ERC) observed from the NOAA-P3 aircraft has 
completed. Not surprisingly, satellite intensity estimates are 
quickly rising, with the latest subjective Dvorak estimate from TAFB 
up to T5.0/90 kt, with the DMINT estimate associated with that 
recent SSMIS pass at 96 kt. Given the continued improvement of Polo 
on satellite, the initial intensity is being increased to 95 kt for 
this advisory.

The intensifying hurricane continues to move a little south of due 
east, with its estimated motion at 105 degrees at 4 kt. This 
short-term motion is expected to continue for the next 12-18 h 
before mid- to upper-level ridging over Mexico intensifies. The net 
result of this synoptic pattern change is that the primary steering 
should flip in about 24 h, causing Polo to make a sharp turn to the 
northwest and then west-northwest in the 36-60 h time frame, 
bringing the core of the hurricane near, but just offshore of, the 
coast of southwestern Mexico. Finally, toward the end of the 
forecast period, Polo will likely be reaching the westward extent of 
the deep-layer ridge. In addition, Polo may also be approaching 
Tropical Storm Odalys that is forecast to be positioned west of 
Polo, and much of the track guidance responds to this evolution by 
showing the hurricane turning more northward by 120 h. There 
continues to be quite a bit of cross-track uncertainty, both in 
terms of how sharp Polo's turn to the northwest will be in the next 
48 h, and also toward the end of the forecast when Polo could 
experience binary interaction with Odalys. The NHC track forecast 
continues to favor a blend of the HFIP Corrected Consensus Approach 
(HCCA) and Google DeepMind ensemble mean (GDMI) aids, but the track 
uncertainly remains high in the 3-5 day period. 

Now that it appears the earlier ERC has completed, it is hard to see 
what could prevent Polo from continuing to RI for the next day or 
so. Shear remains low, analyzed at 6 kt by UW-CIMSS, and there is 
ample deep-layer moisture. Sea-surface temperatures are also very 
warm (31 C) and extend vertically down 50-100 meters along the 
short-term track of Polo per a ARGO profiler, which should limit 
cooler ocean upwelling despite the slow motion of the hurricane. 
SHIPS RI indices continue to be very high, with DTOPS showing an 81 
percent chance of at least a 40 kt increase in intensity over the 
next 24 h. Thus, the NHC intensity forecast will continue to show 
RI, and now shows a 140-kt peak in 24 h. This intensity forecast 
agrees with the HCCA intensity aid, and is also close to the 18z 
HAFS-B forecast which also shows a 140-kt peak in its raw output in 
24 h. Beyond that time, inner-core fluctuations related to 
additional ERCs will likely lead to intensity oscillations, and both 
the GFS- and EC-SHIPS guidance does show a marked increase in 
easterly shear beyond 48 h. Therefore, slow weakening is shown in 
the day 3-5 period, though it still remains a bit higher than the 
intensity guidance consensus aside from HCCA. Regardless, Polo is 
expected to remain a major hurricane through the entire forecast 
period.
 
Key Messages:
 
1. Heavy rainfall associated with Polo will impact coastal portions
of southwest Mexico through Thursday. This rainfall may produce
life-threatening flooding and mudslides, especially in areas of
steep terrain.
 
2. Polo is forecast to strengthen to a major hurricane while it
moves closer to the coast of southwestern Mexico during the next few
days. Although the core of the hurricane is forecast to stay
offshore, it is too soon to determine the exact location or
magnitude of impacts. Residents in southwestern Mexico should
closely monitor its progress and updates to the forecast. A Tropical
Storm Watch is in effect for portions of southwestern Mexico and 
has been extended to Manzanillo. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/0300Z 15.0N 102.3W   95 KT 110 MPH
 12H  22/1200Z 14.9N 101.8W  115 KT 130 MPH
 24H  23/0000Z 15.1N 101.7W  140 KT 160 MPH
 36H  23/1200Z 15.6N 102.2W  140 KT 160 MPH
 48H  24/0000Z 16.5N 103.2W  135 KT 155 MPH
 60H  24/1200Z 17.3N 104.5W  130 KT 150 MPH
 72H  25/0000Z 17.7N 106.0W  125 KT 145 MPH
 96H  26/0000Z 18.6N 109.2W  115 KT 130 MPH
120H  27/0000Z 20.1N 111.7W  105 KT 120 MPH
 
$$
Forecaster Papin