Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
440 FXUS66 KHNX 281819 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1119 AM PDT Thu Aug 28 2025 && KEY MESSAGES... 1. Near normal temperatures through Friday before a warm up Labor Day weekend. 2. 5 to 15 percent chance of thunderstorms over the Sierra Nevada today and Friday. 3. Marginal (5 to 15 percent) risk of flooding in the very high elevations of the Sierra Nevada due to the potential for thunderstorms. DISCUSSION... Moisture in the form of high clouds from the remnants of Juliette have slowly moved southward this morning leading to clearer skies. However, much of this moisture is not going to play a factor in any possible convective activity as thunderstorm chances have decreased to 5 to 15 percent today for the Sierra Nevada and foothills. This is thanks to the ridge of high pressure slowly shifting west towards California bringing a change in the flow. Drier conditions will mostly prevail with at most a 10 percent chance of thunderstorms over the Sierra into next week. Temperatures also will see an increase Labor Day weekend with probabilities of triple digits reaching 40 to 80 percent on Sunday and Monday. The probabilities go down on Tuesday but will remain around 25 to 55 percent for most of the Valley through next Thursday. Fire weather-wise, we are looking at minimum RH of around 15 to 25 percent in the Valley and in the low to mid teens in the Mojave slopes and desert. Winds will be mostly terrain driven the next several days due to the ridge although any thunderstorms in the Sierra can bring gusty winds. AVIATION... 18Z Update: A 5 to 15 percent chance of thunderstorms over the Sierra Nevada and adjacent foothills until 03Z Friday. Otherwise, VFR conditions will prevail 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... None. && $$ JPK weather.gov/hanford