Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
139 FXUS66 KHNX 120437 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 937 PM PDT Fri Jul 11 2025 .UPDATE... Updated Aviation Section. && .KEY MESSAGES... 1. A Heat Advisory has been issued for the San Joaquin Valley an Sierra Nevada Foothills through early next week. 20 to 60 percent chance for greater than 105 degrees in the Valley today and Saturday; 30 to 70 percent chance for Foothill areas to exceed 100 degrees. 2. Low RH values 15 to 25 percent will stretch across much of the San Joaquin Valley and Sierra Nevada with values 5 to 10 percent in the Mojave Desert. RH will decrease over the region later in the week with warming temperatures. 3. 50 to 100 percent chance or temperatures to exceed 105 degrees for much of the Kern Desert over the weekend; 50 to 70 percent chance for Inyokern and Ridgecrest to exceed 110 on Monday. && .DISCUSSION... High pressure has come to a rest over southern California today, leading to an increase in temperatures compared to earlier this week. Widespread triple digit afternoon highs are expected today through the weekend as a result of this synoptic pattern, with a 20 to 60 percent chance for greater than 105 degrees in the San Joaquin Valley today and Saturday and a 30 to 70 percent chance for 100 or more in the Sierra Foothills. For the Kern Desert, there is a 50 to 100 percent chance to exceed 105 each day through Monday. NE Kern County, including Inyokern and Ridgecrest have a 50 to 70 percent chance to exceed 110 on Monday. Due to these warmer temepratures, a Heat Advisory has been issued for the San Joaquin Valley and areas of the Sierra Foothills valid from 11 AM this morning through 11 PM Tuesday. The warming temperatures across the region will cause relative humidity values to decrease, with widespread values between 15 and 20 percent for the valley and mountain areas today, and a slight improvement to 15 to 25 percent Saturday through Monday. Desert RH values will continue to remain largely below 10 percent through the forecast period. A slight cooldown is anticipated in the middle of next week as the aforementioned ridge breaks down. However, temperatures will still be near normal for this time of year. MinRH will improve with the cooler temperatures, with widespread values 25 to 30 percent anticipated for the valley areas. The dry conditions across the region will prolong dry conditions favorable for fire development, however with subsiding air aloft associated with the area of high pressure, winds will generally be light. The strongest winds will be in typical wind- prone areas such as the Mojave Desert Slopes, Lake Isabella, and Pacheco Pass, with the diurnal cycle being the main driver. && .AVIATION... 06Z Update: VFR conditions will prevail for the next 24 hours across the Central California Interior. && .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... Heat Advisory until 11 PM PDT Tuesday for CAZ300>322-324-325- 332. && $$ public/aviation...McCoy/BSO weather.gov/hanford