Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
186 FXUS66 KHNX 191932 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1232 PM PDT Wed Jun 19 2024 .KEY MESSAGES... 1. Temperatures near average through Thursday then warming to 10 to 15 degrees above average this weekend with widespread triple digit maximum temperatures across the lower elevations. 2. An Excessive Heat Watch has been issued for the San Joaquin Valley, West Side Hills, Sierra Nevada Foothills, and Kern River Valley from Sunday morning through late Monday night. A Heat Advisory is in effect for Saturday and Saturday night. 3. There is about a 50 to 85% probability of 105 degrees across the San Joaquin Valley on Saturday and about a 40 to 70% probability of 105 degrees across the San Joaquin Valley on Sunday. && .DISCUSSION... Satellite loops show a few high clouds moving inland over Central CA with the upper-level trough continuing over the Western U.S. Temperatures will continue near seasonal averages today and warm slightly on Thursday. Above average temperatures return by Friday as the ridge of high pressure builds from the Desert SW, and the trough retreats to the Pacific NW and offshore. Some upper-level impulses on Friday may mitigate warming a bit, based on latest high resolution guidance. For this weekend the ridge continues to strengthen, so widespread triple digit heat returns. We have issued a Heat Advisory for the SJ Valley, west side hills, the lower Sierra foothills, and the Kern River Valley for Saturday until early Sunday morning due to hot maximum temperatures and little to no overnight relief. Probabilities remain moderate to high (40-85 percent) for very hot temperatures, or 105 degrees and hotter on both Saturday and Sunday, although with lower chances on Sunday (with the best chances closer to 70 percent in the SJ Valley). For now, we`ll keep the Excessive Heat Watch going for Sunday and Monday, as there remains some uncertainty regarding how much heating occurs. In any case, temperatures will remain hot in much of the lower elevations below 2,500 feet, as well as the Kern County desert, until at least early next week. While confidence is low at this time, there is now a possibility of tropical moisture reaching the desert, though more likely to reach into portions of SE CA closer to the Colorado River by Sunday. This potential feature will bear watching as we get closer, as it could impact southern portions of our forecast area, such as increased cloud cover and perhaps a slight moderation in temperatures. Based on latest guidance, precipitation chances appear mainly limited to far SE CA and the Desert Southwest, or areas to the east and southeast of Kern County, for now. Otherwise, the upper-level ridge of high pressure will remain intact over our forecast area and provide continued dry weather with above average temperatures through the middle of next week. Triple digit heat prevails in the desert and lower elevations from this weekend until at least the first part of next week. && .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... Heat Advisory from 11 AM Saturday to 6 AM PDT Sunday for CAZ300>317-319-321-332. Excessive Heat Watch from Sunday morning through late Monday night for CAZ300>317-319-321-332. && $$ BSO/DAS weather.gov/hanford