Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
801 FXUS66 KHNX 151044 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 344 AM PDT Wed May 15 2024 && .KEY MESSAGES... 1. High temperatures will remain well above seasonal values through Saturday. 2. Strong wind gusts will impact the Mojave Slopes this evening and even strong wind gusts on Thursday evening and overnight. 3. A slight cooling trend is expected to take place beginning this weekend. 4. A few strong thunderstorms are possible in the Sierra Nevada this afternoon and again next weekend. && .DISCUSSION... The weak upper low continues to spin off-shore and is expect to traverse Southern California and by tonight moving into northwest Mexican state of Sonora. This brings the last day of the string of Sierra thunderstorms until they return this weekend. Otherwise, the highlight is above normal temperatures lasting into the weekend. Thunderstorms are possible this afternoon over the Sierra, rising upper heights might be a limiting factor. Otherwise, convective energy is similar to Tuesday afternoon across the spine of the Sierra Nevada. Energy is limited over the Kern County mountains and desert, however is up to 500-850 J/Kg of CAPE that is modest and closer to the upper low that has a very low potential of firing off a thunderstorm over the region. The other new spot is on the coastal range but energy is is generally less than 500 J/Kg. For will continue to limit thunder to the Sierra and not advance to the other areas. THe probability of thunder for this afternoon is as follows: Tioga Pass 2% Yosemite Valley 5% Wawona 3% Grant Grove 5% Three Rivers 6% Sequoia NP 15% Johnsondale 11% Kernville 8% Tehachapi 7% Edwards AFB 6% The the surface gradient between the weak low over the Grand Canyon this evening and Pacific high pressure will set up moderate gusty wind this evening and into the early overnight hours for the Mojave Slopes with the great impact on Highway 58 and Highway 14. The gusts may approach advisory levels, however Thursday looks to pose a great threat to highlight. The PoE of 45 mph for the Slopes is from 30% to 45%. The PoE on 90*F today for the region: Merced 41% Madera 46% Reedley 36% Fresno 81% Lemoore NAS 76% Hanford 66% Visalia 71% Porterville 56% Delano 76% Bakersfield 71% Edwards AFB 91% China Lake NAF >99% Thursday the upper low has pulled off to the east and the Pacific ridge nudges a touch closer to raise upper level heights enough for a slightly warmer day for the San Joaquin Valley. The increase in heights will greatly impact any thunderstorms potential to near zero. The exiting upper low and nudging in ridge sets up a breezy scenario for the Mojave Slopes in the Kern County desert. A tad bit stronger thermal low sets up over the Colorado River Basin with the Pacific Surface slightly increasing the gradient and raising the PoE of 45 mph to near 100% for the Mojave Slopes for the evening and overnight. Thursday continues with well above normal temperatures for the region. Listed below are the Thursday PoE of 90*F and 95*F: Thursday PoE 90F PoE 95F Merced 66% 26% Madera 71% 21% Reedley 71% 6% Fresno 96% 51% Lemoore NAS 96% 41% Hanford 91% 31% Visalia 91% 36% Porterville 86% 16% Delano 91% 31% Bakersfield 91% 31% Edwards AFB 96% 56% China Lake NAF >99% 91% On Friday another upper low over the Pacific begins to impact the region. The impacts are slight just lowering heights a tad keeping the temperatures down a degree or three from Thursday. The PoE of 95*F or greater drops to 10-30% for the SJV and continues higher for the Kern County desert. The PoE of 90*F even drops to 50-80% for the SJV and 86% to near 100% over the Kern County Desert. The Colorado River Valley thermal low slides just enough north and east to keep the nocturnal wind gusts over the Mojave slopes below advisory levels. Saturday the upper low sinks further south in reaction to a stronger wave pushing into the Pacific Northwest. This keeps the Golden State in generally light flow aloft for another day allowing temperature to continue above normal. PoE of 90*F remains in the 40% to 68% for the SJV. The weakness created by the Pacific Northwest system brings back the slim probability of afternoon thunderstorms for the Sierra. Sunday the upper heights lower some as the southern upper low opens into a wave and moves towards Baja California away from the region as another short wave in the upper flow moves into the NW California putting Central California between the system for another above normal day, however slight cooler than Saturday with PoE of 90*F dropping to 20-40% for the SJV. The threat of thunderstorms in the Sierra is near zero with little support. Monday through next Wednesday features a developing upper low that slides down into the Snake River Basin region of the Northwest putting Central California into NW flow with pieces of energy moving through the region. Cluster analysis shows better than average confidence in this pattern developing. The impacts will be temperatures cutting back to near normal. The Mojave Slope wind will have to monitored again with gradients increasing for the region. && .AVIATION... VFR. Very isolated thunderstorms possible mainly over the Central Sierra from 21Z-03Z however probability of occurance remains very low. && .AIR QUALITY ISSUES... ISSUED: 05/14/2024 14:16 EXPIRES: 05/15/2024 23:59 None. && .CERTAINTY... The level of certainty for days 1 and 2 is low. The level of certainty for days 3 through 7 is low. 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 from 7 PM Thursday to 7 AM PDT Friday for CAZ338. && $$ public/aviation/fire weather...Proton DSS....AS weather.gov/hanford