Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
543 FXUS66 KHNX 161930 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1230 PM PDT Wed Jul 16 2025 .KEY MESSAGES... 1. Cooler afternoon temperatures with a slow warming trend going into the weekend. 3. Relative Humidity increasing over the region later in the week. 4. Showers and thunderstorms developing across the Sierra Nevada Crest with a 30 to 60 percent chance from Thursday through Saturday. Light precipitation amounts of less than a tenth of an inch (< 0.10 inch) have the best chances of developing during the event. && .DISCUSSION... The passage of a disturbance on Tuesday allowed for cooling and locally breezy winds across Central California. While the actual frontal zone was centered over the Pacific Northwest, enough energy moved through the area to generate breezy conditions and allow for a push of marine air into the area. Therefore, will see highs this afternoon in the mid 90s as Short-range ensemble Probability of Exceedance (PoE) of reaching 100 degrees is less than 10 percent. PoE of reaching 95 degrees today sits at around 70% to 90% for areas in and south of Fresno County. Therefore, high confidence is seeing 90s this afternoon. Wind-wise, while PoE of reaching and exceeding 35 mph is very low, will see a light afternoon breeze over the ridges and passes today. Probability of Thunder remains very low percentages this afternoon. Therefore, while some convective clouds will form, organized showers will have to wait until the end of the week with the area of weakness over Baja California makes a northward progress and allows for a moisture surge to reach the area. Will see a slow warming trend through Sunday with increasing thunderstorm threats over the Sierra Nevada Crest and light winds until the next cool-down. Ensemble PoE of temperatures will see a slow increase as widespread values struggle to reach 100 degrees until Saturday. By Saturday, PoE of 100 degrees will only range from 20% to 60% with the higher end along the West Side of the San Joaquin Valley. Sunday will see even higher percentages as confidence increase toward those values. Yet, the heat will be short-lived as another disturbance cuts through the region and breaks-down the developing ridge pattern. While higher uncertainty exist in the magnitude of cooling and wind speeds for Monday, will see some change as longer range ensemble upper-air analysis leans in the direction of introducing a trough through the Pacific Northwest early next week. Ensemble precip-water analysis is still showing a northward surge of monsoonal moisture into the area by Friday. While ensemble instability and moisture is very limited on Thursday, they do show a signal toward higher values by Friday. Therefore, while weak convection will be possible on Thursday, will expect better development on Friday. Currently, the area of weakness over Baja is still attempting to overcome the westerlies over the region. As the weak upper low moves north during the next 24 hours, ensemble Probability of Precipitation and Thunder (PoP&T) indicates a 30% chance on Friday (and only a 10% this and Thursday afternoons). By Friday, ensemble precip-water analysis shows higher values overtaking Central California. Yet, uncertainty still exist on the amount of moisture as convection may remain on the drier side. Due to the northward push of monsoonal moisture this week, thunderstorm will be on the drier side and raising fire weather concerns. Thunderstorms will linger on Saturday before clear skies develop on Sunday and continue into early next week. && AVIATION... 18Z Update: VFR conditions will prevail for the next 24 hours across the Central California Interior. && .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. && $$ Public/Aviation....Molina/BSO weather.gov/hanford