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Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
167 FXUS66 KHNX 022040 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 140 PM PDT Tue Jul 2 2024 && .KEY MESSAGES... 1. Above average temperatures continue today, then rapidly warm up to around 15 degrees above normal by Wednesday. This is a dangerous, prolonged heat wave that will last several days with an Extreme Heat Risk. 2. An Excessive Heat Warning remains in effect from Tuesday, July 2nd through Wednesday, July 10th at 8am, and may need to be extended further as the week progresses. 3. The risk of grass fires will continue to increase with herbaceous fuel loading at or near 120% of normal. A long period of excessive heat, minimum relative humidities near 15% and poor overnight relative humidity recoveries will add to the grass fire risk. && .DISCUSSION... The multi-day heatwave has begun today as the high pressure begins moving over California off the Pacific coast. This high pressure system will stay nearly stationary over California for at least the next week, with some long range guidance suggesting impacts from this high pressure system will last through late next week at least. This high pressure system sitting almost stationary over the state will allow temperatures to build at the surface, leading to a dangerous, long-duration heatwave statewide. In particular, the San Joaquin Valley looks to see temperatures hovering around 110 degrees for a few days beginning tomorrow. Probabilities that areas within the San Joaquin Valley will see temperatures greater than 110 rise to a 45 percent chance or above by Saturday, July 6th, from 10-35 percent Wednesday through Friday of this week. These probabilities stay very similar to Sunday. Thus, the two hottest days of the heat wave will be this Saturday and Sunday. Here are probabilities that select cities within the forecast area will see 110 degrees or more as a high temperature for Saturday, July 6th. Bakersfield: 75% Coalinga: 85% Fresno: 60% Hanford: 65% Madera: 45% Merced: 45% Ridgecrest: 96% Visalia: 80% Low temperatures will also be very high for this time of year, with many locations within the valley expected to see values above 70 degrees through the duration of the heatwave. High minimum temperatures lead to poor overnight temperature recovery. Due to these factors, there is extreme HeatRisk forecasted to be widespread throughout the valley beginning on Thursday and lasting at least through next Tuesday. An extreme level of HeatRisk means that the entire population is at very high risk for heat-related illnesses if they do not have access to adequate cooling and hydration. Some safety measures to take include: wearing lightweight clothing, drinking water or sports drinks, and staying inside during the hottest hours of the day. Due to this extreme heat risk, an Excessive Heat Warning has been issued for the San Joaquin Valley, West Side Hills, and the Kern County Mountains and Desert. This warning began today at 11am and will continue through next Wednesday, July 10th, at 8am. Should temperatures around 110 degrees continue to be forecast for the valley beyond next Wednesday, the warning will be extended as necessary. The Climate Prediction Centers long range outlooks are not offering much relief. Both the 6-10 day and the 8-14 day outlook show the San Joaquin Valley with a higher than 50 percent chance of seeing above average temperatures continue through July 12th. && .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. && .FIRE WEATHER... Above normal temperatures, low relative humidities, poor overnight humidity recovery, and dry fuels will continue. The impact issue this afternoon and evenings starting Wednesday into the weekend will feature wind gusts into the teens for the region to add to the fire weather impacts. The best news is that the probability of thunder is near zero for the period ahead. && .AIR QUALITY ISSUES... ISSUED: 07/01/2024 14:37 EXPIRES: 07/02/2024 23:59 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... Excessive Heat Warning until 8 AM PDT Wednesday for CAZ300>322- 324-332-334-336>339. && $$ public/aviation...AS PIO/IDSS..........DCH weather.gov/hanford