Issued at 800 PM MST Tue Oct 07 2025
127 WTPZ41 KNHC 080238 TCDEP1 Hurricane Priscilla Discussion Number 14 NWS National Hurricane Center Miami FL EP162025 800 PM MST Tue Oct 07 2025 While Priscilla remains a large and formidable hurricane, its satellite structure is starting to show signs of decay. The eyewall cloud top temperatures have warmed over the past 3-6 hours, and the last several microwave passes show that the eye is now open to the north. Some of these changes could be due to ocean upwelling, which the hurricane-regional models have been forecasting to occur in the relatively shallow warm waters the large hurricane has been traversing through. While both TAFB and SAB Dvorak CI estimates were constrained at T5.5/102-kt, their data-T numbers have declined, and based on the further degradation on satellite imagery since that time, the initial intensity is being set to 90 kt for this advisory, which is on the lower end of the intensity estimates. Priscilla has resumed a more northwestward motion, estimated at 310/8 kt. The track philosophy remains unchanged, with a northwestward motion at a similar pace expected to continue for the next couple of days as a mid-level ridge remains in place to the northeast of the hurricane. The ridging then becomes eroded and shifted east as a shortwave trough, currently over British Columbia, digs in southward and ultimately cuts off just offshore of the western U.S. coastline. This synoptic evolution will likely cause Priscilla to turn northward from 48-72 hours. However, the cyclone will also become more vertically shallow and may not feel the full effects of the evolving mid-level steering, ultimately slowing down substantially by the end of the forecast. The track guidance this cycle has shifted a little rightward, with the Google DeepMind ensemble mean (GDMI) aid a notable rightward outlier. The NHC track was adjusted a little right, but not as far right as GDMI, staying between it and the reliable HFIP Corrected Consensus Approach (HCCA) aid. It is worth noting there is quite a bit of along track spread in the ensemble guidance in 48-72 h, so the forward motion at the end of the forecast track is more uncertain than usual. The hurricane appears past its peak tonight with the recent structural decline on satellite imagery. While SHIPS guidance indicates sea-surface temperatures (SSTs) under the hurricane should be in the 28 C range, the HAFS-A/B and HWRF SSTs forecast output suggests the large hurricane has upwelled much cooler ocean waters that may take several days for the satellite-based SST methods to properly depict. With this in mind, the NHC intensity forecast is lower than the previous cycle, in good agreement with the intensity aids, showing steady weakening over the next 2-3 days as Priscilla moves into even cooler SSTs. Shear also increases quickly out of the southwest beyond 48 hours, and both the GFS/ECMWF show Priscilla's remaining convection shearing off in 72 h, which will mark when the NHC forecast shows Priscilla as a remnant low near to the central Baja California coastline. The global models show the remnant low dissipating shortly thereafter. KEY MESSAGES: 1. Tropical storm conditions are possible along the Baja California Sur Pacific coastline within the Tropical Storm Watch area tonight into Wednesday. Interests elsewhere in the Baja California peninsula should monitor the progress of Priscilla. 2. Rainfall associated with Priscilla will impact portions of Baja California Sur into Wednesday. Moisture associated with Priscilla will lead to heavy rainfall across west-central Mexico from tonight into Thursday morning and across the U.S. Desert Southwest from late this week into this weekend. This could result in flash flooding, particularly in areas of higher terrain. 3. Swells generated by Priscilla are affecting portions of the coast of southwestern and west-central Mexico as well as the coast of the southern Baja California peninsula. These swells are likely to cause life-threatening surf and rip current conditions, in addition to some coastal flooding. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 20.6N 111.5W 90 KT 105 MPH 12H 08/1200Z 21.4N 112.4W 85 KT 100 MPH 24H 09/0000Z 22.6N 113.7W 70 KT 80 MPH 36H 09/1200Z 23.7N 114.7W 60 KT 70 MPH 48H 10/0000Z 24.9N 115.1W 45 KT 50 MPH 60H 10/1200Z 26.3N 115.3W 35 KT 40 MPH 72H 11/0000Z 27.4N 115.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 12/0000Z...DISSIPATED $$ Forecaster Papin
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