Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
878 FXUS66 KHNX 030937 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 237 AM PDT Wed Jul 3 2024 && .KEY MESSAGES... 1. Today will see a rapid warm up with high temperatures 15 degrees above normal. This is a dangerous and prolonged heat wave that will last several days with an Extreme Heat Risk. 2. An Excessive Heat Warning remains in effect through Wednesday, July 10th at 8 AM, and may need to be extended further as the week progresses. 3. The risk of grass fires will continue with herbaceous fuel loading at or near 120% of normal. A long period of excessive heat, minimum relative humidities near 15% and poor overnight recoveries will add to the grass fire risk. && .DISCUSSION... A very strong ridge is currently just off the west coast, with a strong, lateral ridge stretching across the southern CONUS. The most intense portion of this lateral ridge will over the whole of California be the weekend. This will lead to a great increase in high temperatures beginning today, with highs about 15 degrees above average. Current probabilities for 110 degrees for Wednesday through Friday are 25-50%. As we go into the weekend, the strongest part of the ridge will be directly over Central California, which will increase temperatures even farther, with probabilities for 110 degrees increasing to 60-80% for Saturday and Sunday. Due to a trough on either side, one over the Gulf of Alaska and the other over the Midwest, the ridge will not be able to move, resulting in a prolonged heat wave lasting at least through next week. An Excessive Heat Warning is in effect for the San Joaquin Valley, the West Side Hills, the Sierra Nevada Foothills, and the Kern County Mountains and Desert through the next week, and may need to be extended further as the week progresses due to continued dangerous heat. Overnight recoveries will also be poor, especially in urban areas, with overnight lows greater than 75 degrees, some areas may even see lows no lower than 80 degrees. This heat wave will also come with low relative humidities near 15%, which will increase the fire risk during this time. The SPC has an elevated fire weather risk for the western side of our CWA for the Fourth of July, so it is recommended to forgo fireworks this year to avoid sparking any new fires. && .AVIATION... Continued areas of MVFR and local IFR visibility due to smoke at and around the Fresno County fires will continue in the Sierra Nevada and adjacent foothills. Otherwise, VFR conditions will prevail across the central California interior for the next 24 hours. && .AIR QUALITY ISSUES... ISSUED: 07/02/2024 14:16 EXPIRES: 07/03/2024 23:59 None. && .CERTAINTY... The level of certainty for days 1 and 2 is medium. 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... Excessive Heat Warning until 8 AM PDT Wednesday for CAZ300>322- 324-332-334-336>339. && $$ Public/Aviation/Fire Weather.....EW DSS/PIO..........................VJP weather.gov/hanford