Tropical Cyclone Discussion
936 WTPZ42 KNHC 250856 TCDEP2 Hurricane Polo Discussion Number 19 NWS National Hurricane Center Miami FL EP172026 200 AM MST Fri Sep 25 2026 Since the previous advisory, Polo's eyewall and core cloud-top temperatures have cooled with a very wide and complete ring of cloud-top temperatures below -70C surrounding the eye, with a growing area of cloud-top temperatures colder than -75C surrounding most of the eye. In addition, GOES-18 infrared eye temperatures have warmed significantly since the previous advisory, recently measured near 19C. The latest TAFB Dvorak number is 7.0/140 kt, while DMINT and SATCON have been hovering around 135-136 kt. Based on the improved structure, Polo is assigned an initial intensity of 140 kt for this advisory, making it a category 5 hurricane again. The initial motion is westward, or 275 degrees at 10 kt, so this motion continues to take the hurricane farther away from mainland western Mexico. There is little change to the track forecast philosophy from the previous advisory. Polo is currently being steered by the flow on the south side of a well-defined mid-tropospheric ridge that is building westward over northern Mexico. This steering regime should continue through today. After that, a mid-latitude trough moving eastward across the northeastern Pacific should prevent the ridge from building farther west, with Polo is expected to recurve northward and northeastward around the western periphery of the ridge. The track guidance is generally in agreement on this scenario, although there are still notable differences in forward speed among the models in the 3-5 day time frame. The official forecast is similar to the previous one through 72 hours, but is faster toward the northeast at day 4-5 compared to the previous forecast. The NHC forecast is slightly to the left of the HCCA and Google DeepMind Ensemble Mean through 96 hours, but is to the right of the simple consensus TVCN. Confidence is high that Polo will make landfall in Baja California Sur and then mainland Mexico, after moving through the Gulf of California. Polo will continue to move over very warm waters and in a low vertical wind shear environment through today. Fluctuations in intensity are possible through today. By Saturday, a gradual weakening trend is expected to begin due to some increase in shear. The official intensity forecast is on the high side of the model guidance, and shows the system still near major hurricane strength while it approaches the Baja California peninsula. Rapid weakening is expected when the cyclone crosses the peninsula and moves into mainland Mexico due to land interaction and a further increase in vertical wind shear. It should be noted that moisture from Hurricane Polo and Odalys will be carried a long distance into the southwestern United States this weekend and early next week, 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 approach the Baja California Peninsula early next week as a hurricane. Interests there should closely monitor the latest updates and ensure that they have their preparedness plan in place. FORECAST POSITIONS AND MAX WINDS INIT 25/0900Z 17.2N 107.5W 140 KT 160 MPH 12H 25/1800Z 17.3N 108.9W 140 KT 160 MPH 24H 26/0600Z 17.6N 110.7W 130 KT 150 MPH 36H 26/1800Z 18.5N 112.2W 120 KT 140 MPH 48H 27/0600Z 20.0N 113.2W 110 KT 125 MPH 60H 27/1800Z 21.7N 113.7W 100 KT 115 MPH 72H 28/0600Z 23.3N 113.5W 95 KT 110 MPH 96H 29/0600Z 26.4N 111.2W 80 KT 90 MPH 120H 30/0600Z 29.0N 107.5W 30 KT 35 MPH