Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
651 FXUS66 KHNX 122215 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 315 PM PDT Fri Jul 12 2024 && .KEY MESSAGES... 1. Red Flag Warning in effect through much of the weekend for the Sierra Nevada, which can cause fire ignitions and rapid fire spread with gusts to 50 mph. A Fire Weather Watch for the Tejon Pass and Pine Mountain communities will begin Saturday. 2. Probability of Thunderstorms is 15-30% this weekend with Dry Lightning. There is less than a 10% Probability of a wetting rain. 3. A long-duration, rare heat wave with an Extreme Heat Risk will continue through Saturday night. The Heat Advisory for Yosemite National Park above 5000 feet also continues through Saturday night. 4. The high risk of grass fires in the valley continues, with fire behavior enhanced even with low wind speeds this weekend. && .DISCUSSION... Cluster of strong thunderstorms meandering through Yosemite National Park, Tuolumne Meadows and points north at 10 mph. Downdraft CAPE from SPC Mesoanalysis is through the roof, nearing 1750 J/kg. This is clearly indictitive of an inverted V sounding, which can produce strong downbursts and potentially damaging winds at the surface. In addition, may accompany these storms in the environment, such that dry lightning can start fires and allow them to spread rapidly. Further development along the high Sierra from north to south can occur tonight. An unusually strong shortwave, will continue to sit off the central California coast. Although this anomalous feature is moisture starved, enough southerly flow will accompany it such that orographic and mechianical lifting will occur not only across the Sierra Nevada, Tehachapis but also along Tejon Pass and the Coastal Range. A Fire Weather Watch has been issued for the Frazier Park and Pine mountain club communities. A measely break in our heat wave is shown in the 110F and 105F Probabiltiies of Exceedance which stay below 20% Sunday through much of next week. The strong ridge will be nudged east with a disturbance spinning in the Pacific northwest. As this feature weakens by late week, the heat ridge moves back west, increasing the Probability of Exceedance for 105F Max Temps and 80F Min Temps to 40-50% by next weekend. The Climate Prediction Center`s outlook for Extreme Heat in California has been increased to 40% starting July 20th. The ultimate position of the ridge axis will determine just how hot it will be again, but what might save us from a heat wave similar to the one we`ve seen the past 14 days is that the ridge axis lies just to our east, closer to the Great Basin, which was not the case when Fresno hit 114F this past Monday. && .AVIATION... Areas of MVFR and local IFR visibility will continue in and around wildfires. Thunderstorms, albeit dry will be high based over the Sierra Nevada through the weekend. Otherwise, VFR conditions will prevail across the central CA interior until further notice && .FIRE WEATHER... See previous text. The heavy fuels in the high Sierra have dried out to the point that they now are a fire risk per this morning`s discussion with the Southern Geographical Coordination Center from the US Forest Predictive Services for Fire Weather for California. && .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 high. 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 Sunday for CAZ300>322- 324-325-332-334>339. Red Flag Warning until 9 AM PDT Sunday for CAZ298-299-596. Fire Weather Watch from Saturday morning through Sunday morning for CAZ597. Red Flag Warning until 9 PM PDT Sunday for CAZ592>595. Heat Advisory until 10 AM PDT Sunday for CAZ323. && $$ public...Mattarochia aviation....Mattarochia weather.gov/hanford