Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
743 FXUS66 KHNX 211033 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 333 AM PDT Fri Jun 21 2024 .KEY MESSAGES... 1. Temperatures will rise 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 40 to 75 percent probability for a high temperature of 105 degrees or above across most of the San Joaquin Valley on Saturday and Sunday afternoons. && .DISCUSSION... Satellite loops show mainly clear skies prevailing with just some thin cirrus over Yosemite NP exiting towards Nevada. Temperatures on Thursday topped out right around climatological averages again with lower 90s across the San Joaquin Valley. Upper trough across the region will weaken further today allowing high temperatures to climb to around 4 to 7 degrees above average this afternoon. Highs will mainly be in the upper 90s with probabilities for a max temp of 100 degrees at 21% in Bakersfield and 16% in Fresno and Hanford. The strong upper ridge causing the heat wave across the northeast US will build westward across Texas and the desert southwest this weekend. Temperatures will soar into the triple digits across the lower elevations...generally below 2500 feet, with highs forecast to be 10 to 15 degrees above average. Here are probabilities for a high temperature of 105 degrees or above for some of the larger population areas in the San Joaquin Valley. Sat Sun Merced 41% 31% Madera 51% 41% Fresno 71% 76% Reedley 51% 31% Lemoore 61% 41% Hanford 66% 56% Visalia 66% 56% Porterville 71% 76% Delano 76% 66% Bakersfield 76% 76% These conditions will create a widespread major heat risk across the lower elevations. Not only because of the excessive daytime temperatures but also due to overnight temperatures remain very warm, especially in urban areas. The probability for a low temp of 75 degrees or above Sunday morning is 81% in Bakersfield and 51% in Fresno, due to the urban heat island effect. Probability on Monday morning drops to 51% and 21% respectively. Therefore, a Heat Advisory remains in effect for the San Joaquin Valley, West Side Hills, Lower Sierra Foothills, and Kern River Valley from 11 AM Saturday through 11 AM PDT Monday. Temperatures are expected to nudge slightly lower early next as the ridge remains over the Four Corners region. Max temperatures across the SJ Valley are generally forecast to range from 100 to 105 degrees Monday through Wednesday, around 7-10 degrees above average. Cluster analysis favors the ridge weakening late in the week as an upper trough moves over the Pacific Northwest. Highs are forecast to lower to around 2 to 5 degrees above average on Friday with probabilities for 100 degrees or above falling below 50 percent. && .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. && $$ DCH weather.gov/hanford