Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
748 FXUS66 KHNX 112316 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 416 PM PDT Sun May 11 2025 .UPDATE... Aviation and Air Quality Updated && && .KEY MESSAGES... 1. A disturbance is expected to move through Central California beginning tomorrow, with increased winds and cooler temperatures starting today. Low relative humidity today along with those winds may increase fire risk. 2. A Wind Advisory has been issued for the Mojave Desert Slopes and Kern County Desert for Monday morning through Tuesday night, with sustained winds of 20 to 30 mph and gusts up to 50 mph expected during that time. 3. Cold air aloft may allow for some isolated thunderstorms to develop along the Sierra Nevada crest on Tuesday, with a 15 to 20 percent chance for thunderstorms that afternoon. 4. These storms may also produce little wetting rainfall as the probability for a tenth of an inch that afternoon is 10 to 25 percent. This along with lightning strikes increase the chance for new fire starts. && .DISCUSSION... A weather disturbance in the form of a trough has begun to influence Central California today by causing breezy winds in the San Joaquin Valley and cooling temperatures throughout the region. And while this is happening, relative humidities are expected to be around the same values (15 to 20%) today, so combined with the increased winds, these conditions make any fire that may start more likely to spread faster than they would otherwise. The dry fuels would also increase the intensity of any fires should one start. As the trough fully passes over the region, winds along the Mojave Desert Slopes and Kern County Desert are expected to become strong, with sustained winds of 20 to 30 MPH and gusts up to 50 MPH expected while the trough is passing through, the strongest of which are expected on Tuesday. A Wind Advisory has been issued for this area from Monday morning through Tuesday night. The Sierra Nevada crest and the lee side of the mountain range will also see these winds. Also on Tuesday is a 15 to 20 percent chance for thunderstorms in the Sierra Nevada, due to the incoming cold air allowing for low top thunderstorms to more easily develop. Any storms that develop may produce lightning and, as models are currently showing, little chance (10 to 25%) for a wetting rain of at least a tenth of an inch. That means these storms are more likely to produce dry lightning, which increases the chances for new fire starts. The trough is expected to move out of the region by Wednesday afternoon, with a mostly zonal flow following it. This means temperatures are expected to be a few degrees above normal, but otherwise calm weather will return. Minimum relative humidity is also expected to decrease after the passage of the trough, though lighter winds would reduce the fire risk for the rest of the week. Next weekend is beginning to see another trough coming into the west coast, however one ensemble model has the most intense portion of this trough to the northeast of our CWA and just scrape the Sierra Nevada and another has it passing over our CWA, which would pretty significantly change how this weather system would impact the region. These models will eventually come together in the next few days to give us a better picture on this potential event. && .AVIATION... 0Z Update: VFR conditions are expected for the next 24 hours in Central California. && .AIR QUALITY ISSUES... ISSUED: 05/11/2025 14:50 EXPIRES: 05/12/2025 23:59 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... Wind Advisory from 8 AM Monday to 2 AM PDT Wednesday for CAZ337>339. && $$ public...EW/SM aviation....JPK weather.gov/hanford