Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
806 FXUS66 KHNX 220505 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1005 PM PDT Mon Jul 21 2025 .UPDATE... Aviation Section Updated && && .KEY MESSAGES... 1. Temperatures for the next week are expected to be below normal for this time of year beginning today. Tomorrow through this weekend, many locations in the Valley will struggle to reach 90 degrees in the afternoon. 2. Slightly breezy winds can be expected through the Valley and stronger winds along the Mojave Slopes as well during this && .DISCUSSION... Weak troughing has moved into Central and Southern California this morning as the main trough moves into Oregon and Washington state, and will dominate over the region throughout this week, bringing cooler this average temperatures and slightly breezier winds to the Valley and stronger winds to the Mojave Desert. This trough will remain in place due to the strong ridge that has taken over the CONUS to the east of the Rocky Mountains. Since this troughing will cause a decrease in overall temperatures, the afternoon RH percentage values in the Valley are expected to rise slightly into the 30`s and 40`s, taking the Valley out of the persistent low RH`s in the 15 to 25% range. These RH`s are expected to remain at a similar range through this weekend along with the cooler temperatures. These factors together will help to reduce the fire risk in the region, though the increased winds would work in the opposite direction. Current long term models are indicating a warming trend beginning again by next Monday and continuing through that week, with the ridge that is currently over the eastern CONUS possibly retrograding west and causing an increase in 500mb heights over the whole of California. Looking further out into next month, the Climate Prediction Center has our area in a 40 to 50% chance for above normal temperatures, as indicated by the current models. && AVIATION... 00Z Update VFR conditions are expected in the San Joaquin valley for the next 24 hours. Winds of 15-20kts are expected between 01Z to 08Z Tuesday. && .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...EW aviation....JPK weather.gov/hanford