Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
249 FXUS66 KHNX 101800 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1100 AM PDT Sun Aug 10 2025 .KEY MESSAGES... 1. Heat-wave started this weekend as triple digit heat expected through at least Tuesday. 2. Extreme Heat Warning for the Kern Desert Today and Monday with a 40 to 60 percent chance of Desert temperatures reaching 110 degrees both days. 3. Heat Advisory for the San Joaquin Valley Today and Monday with a 50 to 70 percent chance of Valley temperatures reaching 105 degrees both days. 4. Minor fire risk with widespread minimum relative humidity between 15 and 25 percent for the non-desert areas. Minimum relative humidity expected to be less than 10 percent in the Mojave Desert with breezy winds in the afternoon to evening. && .DISCUSSION... Heat-Wave underway as triple digit heat takes over the Central California Interior. Ensemble High-Res Short-range upper-air analysis has seen further amplification of the associated high pressure ridge over the West. While Probability of Exceedance (PoE) of reaching 100 degrees is very high through-out Central California, it is now time to consider the PoE of 105 and 110 degrees. Even as 24 hour change in temperature backing off on running warmer, PoE now has a much wider coverage of PoE at or above 50%. This holds true for this afternoon and Monday. Across the Kern Desert, the 10th to 90th percentiles shows a range of possible values between 105 and 111 degrees, respectively. With a mean max temperature above the 10th percentile, a very hot day is in store for the Kern Desert today and Monday. Will opt for an Extreme Heat Warning for Today and Monday as expected highs will reach critical heat criteria. Little change is expected through Tuesday ahead of a disturbance that will begin a cooling trend by Midweek. Until the ridge pattern breaks down due to a passing Pacific Northwest disturbance, the region will be dominated by the heat. The onset of significant temperature changes is expected between Wednesday and Thursday as temperatures trend toward seasonal normal values. By Thursday the chances of reaching 100 degrees tapers off as pockets of PoE above 50% will exist across the area. On Friday, PoE of 50% become non-existent as max temperatures are expected to drop below triple digit values. The initial arrival of the Pacific disturbance will introduce marine moisture into the region and spark afternoon convection across the Sierra Nevada Crest on Tuesday. Moisture will be limited with brief showers over the high mountain terrain. Additional disturbance moving through the are later next week will maintain a good westerly flow and prevent a rebound of the heat-wave through at least next weekend. && .AVIATION... 18Z Update: 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 from 2 PM this afternoon to 5 AM PDT Tuesday for CAZ337>339. Heat Advisory until 11 PM PDT Monday for CAZ300>317-319-321. && $$ public...Molina aviation....JPK weather.gov/hanford