Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
113 FXUS66 KHNX 281019 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 319 AM PDT Fri Jun 28 2024 && .KEY MESSAGES... 1. Gusty winds will continue early this morning along the Mojave Desert Slopes. A Wind Advisory remains in effect from through 8 AM PDT. 2. A warming trend will begin today across central California with temperature this afternoon 2 to 4 degrees above season normals. 3. Maximum temperatures are expected to rise above 100 degrees again over the lower elevations by Saturday and above 105 degrees by next Tuesday. 4. Temperatures will approach 110 degrees in the valley and desert areas Wednesday, with triple digit heat continuing into next weekend. An Excessive Heat Watch is in effect from Tuesday through Saturday. && .DISCUSSION... Zonal flow aloft currently propagating over central California will give way to southwesterly winds entering the weekend as an upper level low pressure system makes its way through the Pacific Northwest region. Temperatures are projected to gradually increase with the change in the synoptic pattern. Ensemble guidance from the National Blend of Models expresses a 10 to 40 percent probability for afternoon temperatures to exceed 100 degrees in the San Joaquin Valley this afternoon; however, these probabilities jump to 40 to 70 percent for Saturday and Sunday. Similar probabilities exist for temperatures to exceed 105 degrees in the Kern County Desert through the weekend. A Wind Advisory continues in the Mojave Desert Slopes through 8 AM PDT this morning due to sustained northwest winds 15 to 25 miles per hour with gusts up to 45 miles per hour. Stronger winds are also expected in the San Joaquin Valley this evening, with the HREF ensemble suggesting a moderate to high (50 to 80 percent) probability for wind gusts greater than 20 miles per hour. This, coupled with minimum relative humidity values between 10 and 15 percent during the afternoon has led to an increase in fire danger across the valley areas, especially where large areas of dry grasses are prevalent. The end of the weekend will bring the start of a change in the upper level synoptic flow for the western United States. A strong upper level ridge is projected to build over California from the eastern Pacific, remaining relatively stationary over the region through the week. The stagnant and subsiding air aloft will create a sharp uptick in probabilities for triple digit heat across our forecast area. NBM ensemble guidance shows a 70 to 90 percent probability for 100 degrees in the San Joaquin Valley each day next week between Tuesday and Sunday. Early indications show Wednesday, July 3rd to be the warmest day, with ensembles giving a 75% chance for afternoon temperatures at least 105 degrees and a 25% chance to exceed 109 degrees. An Excessive Heat Watch has been issued due to the continuous triple digit heat, valid from 11 AM PDT Tuesday through 5 AM PDT Saturday. The aforementioned ridge will also bring clear conditions to the region during the week, offering little reprieve from the heat. && .AVIATION... Areas of MVFR and local IFR visibility due to smoke in the Sierra Nevada and adjacent foothills south of King Canyon. Wind gusts above 35 knots are possible in the Mojave Desert Slopes through 15Z this morning, producing local blowing dust. Otherwise, VFR conditions will prevail across the central California interior for the next 24 hours. && .AIR QUALITY ISSUES... Air Quality Alert due to smoke impacts from wildfires. && .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... Wind Advisory until 8 AM PDT this morning for CAZ338. Excessive Heat Watch from Tuesday morning through late Friday night for CAZ300>322-324-332-334-336-338. && $$ public/aviation...SM IDSS.............DAS weather.gov/hanford