Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
616 FXUS66 KHNX 180440 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 940 PM PDT Sat May 17 2025 .UPDATE... Aviation Section Updated && && .KEY MESSAGES... 1. A cooldown occurs this weekend, with gusty winds by Saturday afternoon over the mountain ridges and peaks, as well as the Kern County desert. Elsewhere, winds will be noticeably stronger. 2. A 10-15 percent chance of afternoon and evening thunderstorms exists in the Sierra Nevada today. 3. Increased winds combined with low humidity on Sunday and Monday will lead to a risk for large grass fires in the San Joaquin Valley. 4. Well above normal temperatures and mainly dry conditions are expected Tuesday and the remainder of next week. && .DISCUSSION... Satellite loops show mainly mid-level and high clouds due to an upper-level trough over the WFO Hanford Warning/Forecast area. Noticeably cooler temperatures and stronger winds will take place today and Sunday as the trough continues its trek over the Great Basin. Much of the moisture and dynamics has been passing to our north, although a slight chance of thunderstorms is forecast for the Sierra Nevada, though mainly in the higher elevations. The chances for thunderstorms today are around 10-15 percent. Forecast precipitation amounts are light, or up to a few hundredths of an inch with a dusting of snow over the highest elevations. Strong and gusty winds develop later today in the Kern County desert and over the ridges and peaks along the Sierra Nevada crest, with the highest impacts likely at the Mojave Desert slopes (including Mojave). The probability for a gust of at least 55 mph is 75-95 percent along the Mojave Desert slopes and nearby areas just below, with the peak strength during this evening. In addition, the risk, while relatively low, for large grass fires exists in the Central Valley on Sunday due to the combination of lower humidity with breezy conditions redeveloping. Winds on Monday won`t be quite as strong, but the temperatures will be warmer than on Sunday and will keep daytime humidity low. So, the possibility for Monday will remain. Enjoy the mild, more spring-like temperatures this weekend, as a longer period of above average temperatures commences early next week. A ridge of high pressure will build and remain anchored over much of the Southwestern U.S. from Monday and the rest of next week. Monday`s highs will be slightly above average, but the warming will become more noticeable by Tuesday. Probabilities for highs in the 90`s in the warmest locations are at a minimum of 70 to 90 percent for Tuesday until at least the next few days. Triple digit heat becomes a possibility once again by Thursday, including in both the SJ Valley and Kern County desert, or at 20-40 percent chance. Other locations besides Kern County could see their first triple digit day for this year by then. While probabilities for triple digit readings are a bit lower for next Friday (about 10-25%, with the best chances in the desert), summer-like temperatures could persist for a little while based on the latest 6-10 and 8-14 day outlooks from the Climate Prediction Center, with a probability of above 50 to 60 percent of above average temperatures for the latest 6-10 day outlook and about 35-40 percent chance on the 8-14 day outlook. && .AVIATION... 00Z Update: MVFR with local IFR in mountain obscurations possible over the Sierra Nevada, from Yosemite NP to Sequoia NP, due to a slight chance (around 15 percent) showers/thunderstorms through 06Z Sunday. Westerly winds will continue to be strong through 09Z Sunday in the Kern County desert and adjacent slopes with gusts 45-55 kts. Otherwise, VFR conditions will prevail for the next 24 hours across the Central California Interior. && .AVIATION... 6Z Update: Westerly winds will continue to be strong through 09Z Sunday in the Kern County desert and adjacent slopes with gusts 45-55 kts. Otherwise, VFR conditions will prevail for the next 24 hours across the Central California Interior. && .AIR QUALITY ISSUES... ISSUED: 05/17/2025 12:53 EXPIRES: 05/18/2025 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... High Wind Warning until 2 AM PDT Monday for CAZ338. Wind Advisory until 2 AM PDT Sunday for CAZ337-339. && $$ public...BSO/EW aviation....JPK weather.gov/hanford