Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
101 FXUS66 KHNX 071932 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1232 PM PDT Fri Jun 7 2024 && .KEY MESSAGES... 1. An Excessive Heat Warning remains in effect for the lower elevations through 8 PM today. 2. The Heat Risk will be major (red) today, which will impact anyone without effective cooling and/or adequate hydration. Impacts are likely in some health systems, heat-sensitive industries and infrastructure. 3. Temperatures will lower this weekend, but are forecast to still be around 3 to 6 degrees above normal by Sunday. 4. The anticipated heat could lead to increased snowmelt over the Sierra Nevada, resulting in colder and higher flows along rivers and waterways. 5. Another round of triple digit heat is forecast by the middle of next week, with probabilities of afternoon highs exceeding 100 degrees in the San Joaquin Valley between 50 and 70 percent. && .DISCUSSION... The Excessive Heat Warning for the San Joaquin Valley and Kern County deserts will expire at 8 PM tonight as the ridge that brought the extreme heat moves to the interior West. The warning will expire as the overnight temperatures will trend lower as the pattern changes. Latest model ensembles show a shortwave trough sliding down off the coast over a weekend along with the moving ridge will bring temperatures down but will remain average. The ensembles are showing that the trough will become a cutoff low on Monday into Tuesday with a ridge building above it in the Pacific Northwest leading to the formation of a rex block. Temperatures are expected to cool down over the weekend but will remain 3 to 6 degrees above average. Saturday has a 50 to 65 percent chance of high temperatures of at least 95 degrees for most of the Valley while the northern locations such as Merced and Madera have a 25 to 35 percent chance of highs of at least 95 on Saturday. The probabilities go down on Sunday to a 25 to 50 percent chance of a high temperature of at least 95 degrees with Merced near 15 percent chance. Latest probabilities have the next chances of triple digits on Tuesday as the rex block forms with a 50 to 65 percent chance of a high temperature of at least 100 degrees for the entire valley. The probability increases on Wednesday to a 60 to 70 percent chance of triple digits for the entire Valley. There is a 10 to 20 percent chance of thunderstorms in the higher elevations of the Sierra Nevada in Tulare and southern Fresno County for this afternoon. The potential continues tomorrow for the higher elevations of the Sierra with a 5 to 15 percent chance of thunderstorms. && .AVIATION... 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 8 PM PDT this evening for CAZ300>317-319-321-332-337>339. && $$ JPK weather.gov/hanford