Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
417 FXUS66 KHNX 211848 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1148 AM PDT Fri Jun 21 2024 .KEY MESSAGES... 1. Temperatures will rise to around 10 to 15 degrees above average this weekend with widespread triple digit afternoon highs across the lower elevations. A Heat Advisory is in effect from Saturday through Monday morning. 2. There is a 50 to 80 percent probability for a high temperature of 105 degrees or above across most of the San Joaquin Valley on Saturday and Sunday afternoons. 3. Above average temperatures continue until the middle of next week, with triple digit heat persisting for many locations. && .DISCUSSION... Mainly dry conditions will continue today with temperatures about 3-5 degrees warmer than this time yesterday. This afternoon`s highs are on track to reach the upper 90`s at the warmest valley spots, along with some triple digits in the Kern County desert. The warming trend continues this weekend as the upper-level trough over the Pac NW weakens and moves inland while the ridge builds into our forecast area from the Desert Southwest. Widespread triple digit heat returns Saturday and lingers into early next week. The best chances for a high of 105 degrees and hotter will be on Saturday and Sunday (at 50-80 percent) with lowering probabilities starting early next week. We will continue the Heat Advisory for this weekend into early next week, as the heat risk remains at the moderate to high levels until Tuesday morning. Little relief during the overnights is in store once we heat up, including for vulnerable and sensitive populations, as well as the largest urban areas in the SJ Valley and the higher terrain towards the south end of the valley where lows will struggle to drop below the mid-70`s. As some mid- level tropical moisture due to the remnants of TS Alberto (that was over the Gulf of Mexico earlier this week) passes over Southern CA, there is the potential for isolated thunderstorms in the mountains and desert in Kern County. The chances at this time are mainly about 10 percent by Sunday morning and as early as late Saturday night. If we don`t get thunderstorms, we would otherwise see an increase in mid-level clouds and humidity. Chances for thunderstorm are a little higher for the mountains of LA/Ventura/SBD Counties and nearby desert portions. It is more certain that we will be very hot on Sunday and again on Monday. The probability of highs at or above 105 degrees in the Central Valley remain at around 20 to 40 percent and 40 to 60 percent for the Kern County desert on Monday afternoon. In addition, overnight lows will continue warm into Tuesday morning. We will still see triple digit heat Tuesday until Thursday as the ridging remains in place over the area. Chances for a high at or above 100 degrees in the SJ Valley are around 30 to 60 percent for Tuesday until Wednesday, though even higher for the Kern County desert. Lower probabilities of triple digits exist for Thursday, although it is more uncertain for this lead time. In addition, the overnight lows won`t be quite as warm. && .AVIATION...VFR conditions will prevail across the Central CA interior for 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... Heat Advisory from 11 AM Saturday to 11 AM PDT Monday for CAZ300>317-319-321-332. && $$ BSO/SM weather.gov/hanford