Issued at 200 PM MST Sun Oct 05 2025
000 WTPZ41 KNHC 052042 TCDEP1 Hurricane Priscilla Discussion Number 5 NWS National Hurricane Center Miami FL EP162025 200 PM MST Sun Oct 05 2025 Priscilla has become markedly better organized this afternoon. A well-defined curved band has formed along the southern semicircle of the tropical cyclone, and there have been occasional hints of a ragged eye showing up on the visible images. A scatterometer pass at 1713 UTC showed the circulation has become better embedded in the central dense overcast, though there haven't been any recent high-resolution microwave images to confirm that Priscilla is better vertically aligned. Subjective Dvorak fixes from SAB and TAFB still support T4.0/65 kt, and the objective estimates from UW-CIMSS are also increasing, now in the 59-66 kt range. Thus, the initial intensity is being increased to 65 kt, making Priscilla the 10th hurricane of the 2025 Eastern Pacific Season. Wind radii were also adjusted based on the earlier scatterometer data. The hurricane continues to move very slowly, with a best guess at an estimated motion of 330/3 kt. There isn't much change to the track reasoning, with the current lack of motion mainly due to light steering currents from a weak ridge eroded by a larger mid- to upper-level trough over the western Gulf and Texas. This feature is expected to lift out, allowing the ridging over Mexico to gradually become re-established. The end result should cause Priscilla to gradually accelerate to the north-northwest with a subtle bend leftward over the next 2-3 days. There remains a notable amount of spread in the track guidance in 72 hours, with the GFS continuing to be on the far south and west side of the guidance envelope, and the ECMWF on the north and east side. The NHC track forecast is very similar to the prior one, splitting the difference between these outliers, and lies close to a blend of the HCCA and GDMI track aids. Shear analysis from UW-CIMSS indicates that the Priscilla is experiencing 20 kt of east-northeasterly shear, and yet the cyclone has been able to intensify, likely aided by plenty warm sea-surface temperatures, and ample deep-layer moisture. The shear is expected to stay about the same in magnitude over the next 2-3 days, and in general the intensity guidance has come up from the previous cycle. SHIPS rapid intensification (RI) indices are elevated, and if Priscilla can establish a tighter inner core, it is not out the question the hurricane could intensify more than shown here. For now, the NHC intensity forecast will show more gradual intensification, assuming the shear tempers a faster rate of deepening, but now has peak of 90 kt, a little higher than before. This is a bit higher than the HCCA intensity aid, but lower than some of the more aggressive models (HAFS-A/B, COAMPS-TC, Florida State Superensemble). After 72 h, Priscilla is forecast to move over a sharply cooling sea-surface temperature gradient, which should induce rapid weakening by the end of the forecast period. KEY MESSAGES: 1. Tropical storm conditions are possible along portions of the coast of southwestern Mexico within the watch area through Monday. Interests in the southern portion of Baja California Sur should also monitor the progress of Priscilla. 2. Heavy rainfall associated with Priscilla will impact coastal sections of southwestern Mexico through Monday, which could result in flash flooding, particularly in areas of higher terrain. 3. Swells generated by Priscilla are affecting portions of the coast of southwestern Mexico and will reach the coasts of west-central Mexico and the southern Baja California peninsula by Monday. These swells are likely to cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 05/2100Z 16.4N 107.1W 65 KT 75 MPH 12H 06/0600Z 16.8N 107.3W 70 KT 80 MPH 24H 06/1800Z 17.7N 108.1W 75 KT 85 MPH 36H 07/0600Z 18.6N 109.1W 80 KT 90 MPH 48H 07/1800Z 19.5N 110.4W 90 KT 105 MPH 60H 08/0600Z 20.4N 111.7W 90 KT 105 MPH 72H 08/1800Z 21.4N 113.0W 80 KT 90 MPH 96H 09/1800Z 23.6N 115.4W 60 KT 70 MPH 120H 10/1800Z 25.4N 116.6W 35 KT 40 MPH $$ Forecaster Papin
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