Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
826 FXUS66 KHNX 240600 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1100 PM PDT Sat Aug 23 2025 .UPDATE... Updated for 06Z Aviation. && .KEY MESSAGES... 1. Unseasonably warm temperatures continue this weekend with widespread triple digit heat. 2. An Extreme Heat Warning for the Kern Desert continues through Sunday morning. An Extreme Heat Warning also continues for the Sierra Foothills and the urban areas of the San Joaquin Valley. A Heat Advisory remains in effect for the rest of the rest of the valley and for the Lake Isabella area. 3. A Red Flag Warning continues for the Frazer Park, Grapevine, and Fort Tejon areas in southern Kern County valid through this evening due to low relative humidity and locally breezy winds. 4. There is a 10 to 30 percent chance for thunderstorms each afternoon starting today due to an influx of monsoonal moisture across the area, with the greatest chances along the Sierra Crest. Isolated thunderstorms will continue over the Kern County desert and even move into the Sierra Nevada foothills and the Central Valley at times this weekend and early next week. && .DISCUSSION... Monsoonal moisture continues to flow into Central California thanks to the ridge of high pressure that has set up over much of the Southwest U.S. Expect much above average temperatures once again today, but with increased humidity and cloud cover at times. Thunderstorms have moved into the San Joaquin Valley, particularly Kern County, such as near Delano and Taft as of the time of this writing. Isolated to scattered thunderstorms are also passing over the higher elevations of the Sierra in much of Tulare County into Fresno County. Expect activity to continue to spread to the lower elevations this afternoon and into the evening. A daily threat of showers and thunderstorms will continue into at least the middle of next week over at least the mountains and desert. Temperatures will gradually lower as we head into next week, but will remain at least several degrees above average through early next week. Heat products will continue into Sunday morning for the desert and some portions of the Central Valley and foothills (including northern portions). However, the heat warning/advisory has been extended into Monday morning for Fresno County southward. && .AVIATION... 06Z Update: A 15 to 30 percent chance of thunderstorms over the Sierra Nevada and adjacent foothills and a 5 to 15 percent chance of thunderstorms over the valley and desert for the next 24 hours. Otherwise, VFR conditions are expected in the San Joaquin Valley for the next 24 hours. && .AIR QUALITY ISSUES... None. && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... Extreme Heat Warning until 8 AM PDT Sunday for CAZ300-317- 337>339. Heat Advisory until 8 AM PDT Sunday for CAZ301>303. Extreme Heat Warning until 8 AM PDT Monday for CAZ304-307-308- 313-314-316-319-321. Heat Advisory until 8 AM PDT Monday for CAZ305-306-309>312-315- 332. $$ BSO/SM/CM weather.gov/hanford