Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
688 FXUS66 KHNX 111958 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1258 PM PDT Thu Jul 11 2024 && .KEY MESSAGES... 1. A long-duration, rare heat wave with an Extreme Heat Risk will continue through late this week will have many impacts on all of our citizens and all sectors of the community. 2. An Excessive Heat Warning remains in effect until Saturday, July 13 at 10 AM. A Heat Advisory remains in effect for Yosemite NP through Thursday at 10 AM. 3. The high risk of grass fires will continue with herbaceous fuel loading at or near 120% of normal exhibiting behavior typically not experienced with low wind speeds. 4. Chance of afternoon thunderstorms returns to the higher elevations of the Sierra Nevada this weekend as high level moisture spreads over the district. 5. A Red Flag Warning in the Sierra Nevada will be in effect from 11 Am Saturday through 9 PM Sunday due to a 30% chance of dry thunderstorms. && .DISCUSSION... The ridge of high pressure which has been acting like a gigantic pressure cooker remains in the area leading to temperatures climbing back to near record today and Friday. This afternoon, we have a 50 to 80 percent probability of high temperatures of at least 113 degrees which would break records for many locations including Fresno and Bakersfield. The probability goes down a bit for a high of at least 113 degrees on Friday to a 40 to 70 percent chance. Latest model ensembles are in agreement that this persistent ridge will loosen its grip as it slides east towards the Four Corners. The shift in the ridge with a shortwave trough off the coast of California will introduce a southeasterly flow at the higher levels bringing in some moisture to our area. This moisture will help produce thunderstorms and dry lightning. Latest probabilistic models have up to a 30 percent chance of thunderstorms in the Sierra Nevada which in combination with the low fuel moisture has led to the issuance of a Red Flag Warning from 11 AM Saturday through 9 PM Sunday. As the ridge continues to move east of the area, a southwesterly flow from the Pacific Ocean will develop helping bring temperatures down in the San Joaquin Valley by the middle of next week. However, this southwesterly flow is part of another ridge developing over the interior Northwest. Latest probabilities show a decrease in temperatures. By Wednesday, there is a 40 to 50 percent probability of a high temperature below 100 degrees for most of the Valley. However, temperatures will be at or slightly above normal for most of next workweek. && .AVIATION... Areas of MVFR and local IFR visibility will continue in and around wildfires. Otherwise, VFR conditions will prevail across the central CA interior 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... Excessive Heat Warning until 10 AM PDT Saturday for CAZ300>322- 324-325-332-334>339. Red Flag Warning from 11 AM Saturday to 9 PM PDT Sunday for CAZ592>595. Heat Advisory until 10 AM PDT Friday for CAZ323. && $$ JPK weather.gov/hanford