Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
348 FXUS66 KHNX 111825 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1125 AM PDT Sat May 11 2024 .KEY MESSAGES... 1. A warming trend is expected today and Sunday. 2. By Sunday afternoon, high temperatures will be around ten degrees above normal for this time of year. 3. High temperatures will remain well above seasonal values Monday through Friday. 4. A few strong thunderstorms are possible in the Sierra Nevada Sunday afternoon, Monday afternoon, and Tuesday afternoon. && .DISCUSSION... Now that the upper level disturbance over Las Vegas on Friday has shifted toward the Four Corners region, the threat of mountain thunderstorms has diminished. Sunny skies will be observed today with temperatures slightly warmer as a ridge of high pressure shifts more onshore. Central California saw a few locations hit the 90 degree mark on Friday. With the ridge shifting towards us, will see more locations hit the 90 degree mark today as max temperatures are expected to peak out in the mid 90s this weekend. While moisture and instability remain over the region, a lifting mechanism (short-wave trof) will return on Sunday/Monday for a continuation on mountain thunderstorms early in the week. Afterward, the ridge rebuilds for and maintains the area with warm and dry conditions for the remainder of the period. In the past 24 hours, ensemble surface temperature analysis has increased the Probability of Exceedance (PoE) of reaching 90 degrees across the San Joaquin Valley to values in the 50 to 70 percent range. Therefore, confidence is high that scattered 90 degree readings on Friday will become widespread this Saturday. Ensemble then increase the PoE by another 10 percent on Sunday which adds to the confidence that some locations will hit the mid 90s. While confidence values drops slightly on Monday as a short-wave trof passes over Northern California, PoE are still high enough (60-70 percent range) to maintain 90s working into Monday and Tuesday. During the same time, the short-wave trof that is expected to cross over Northern California will provide enough lift to re-generate convective activity starting on Sunday. Ensembles are currently placing Probability of Thunder (PoT) in the 15-20 percent range on Sunday across the Sierra Nevada with almost double the percentage on Monday (around 25-35 percent). Will mention thunder from Sunday through Tuesday with the best chances on Monday (35 percent). As the disturbance exits on the area on Wednesday, will return to a dry and warm pattern over the West Coast. Long-term analysis is not a dry-cut as the short-term. Ensemble error grows as weather models show high uncertainty values. Cluster Upper-Air Analysis does hint toward favoring a trof solution toward the end of next week. The break down of the ridge is also reflected in PoE of reaching 90 degrees later next week. Ensemble are showing PoE percentage values dropping below 40 percent heading into next weekend. At this point, uncertainty is still too high mention organized precipitation, yet, lean toward increasing cloud cover over the Sierra Nevada until better ensemble agreement is reaching during the week. && .AVIATION... VFR conditions will prevail across Central California for at least 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... None. && $$ Operations.......Molina Support/IDSS.....DS weather.gov/hanford