Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
651 FXUS66 KHNX 051839 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1139 AM PDT Thu Jun 5 2025 && .KEY MESSAGES... 1. Minor Heat Risk is expected in the San Joaquin Valley today before Moderate Heat Risk returns tomorrow into mid next week. 2. There is a 15 to 30 percent chance for thunderstorms in the Sierra Nevada mountains in the afternoon today and tomorrow, with the Storm Prediction Center issuing a General Risk for thunderstorms in the mountains for both of these days. && .DISCUSSION... Current satellite imagery shows the steady buildup of cumulus clouds over the Sierra Nevada mountains. These clouds are the precursor to the thunderstorms that may develop later this afternoon. The chances for these storms to form is 15 to 30% and they are most likely to form from 11 AM through 5 PM, though they could stick around until 8 PM or just before sunset. Similar chances for thunderstorms exist tomorrow in the same area at a similar timeframe. Any cell that develops may produce localized heavy rainfall and frequent lightning. Over the weekend, the chances for thunderstorms in the Sierra Nevada still exist, however those chances are slightly lowered at 10 to 20% in the afternoon. This warming trend is expected to continue through the weekend into next week, with today being the last day the Valley will see just a Minor Heat Risk before becoming a more Moderate risk tomorrow. This Moderate Heat Risk is expected to continue through at least Wednesday, before a slight cooling trend is expected to begin. Next Thursday so far has a mix of Minor and Moderate forecast for the Valley, though this may change in the coming days as the forecast is refined. Relative humidity during the upcoming week is expected to steadily decline, where values will generally be between 15 and 20 percent in the Valley by Wednesday. && .AVIATION... 18Z Update: VFR conditions will prevail for the next 24 hours across the Central California Interior. A 15-30 percent chance of thunderstorms exists in the Sierra Nevada from 18Z Thu through 03Z Fri. && .AIR QUALITY ISSUES... ISSUED: 06/04/2025 14:37 EXPIRES: 06/05/2025 23:59 None. && .CERTAINTY... The level of certainty for days 1 and 2 is medium. 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. && $$ Public/Aviation/Fire Weather...EW DSS/PIO........................SM weather.gov/hanford