textproduct: San Joaquin Valley

UPDATE

Updated Aviation Section.

KEY MESSAGES

1. Moderate chance for dense fog and visibilities less than one-quarter mile in the Central Valley Sunday morning.

2. Above average temperatures continue across the region. Low minimum relative humidities, especially in the Sierra Nevada.

3. Precipitation chances return next weekend.

DISCUSSION

We may start sounding like a broken record in these discussions over the next few days with very few changes expected in the overall synoptic pattern until next weekend. Today through Thursday, a ridge of high pressure is expected to remain in place over the Desert Southwest and much of Central and Southern California. Low level and near surface air will continue to be around ten degrees above season averages through this period, trapped under the subsidence inversion, and unable to escape the California interior horizontally due to the local terrain. Warmer temperatures will also generally result in drier conditions, as the air becomes less saturated. This will be most apparent in the Sierra Nevada and Foothills above 4,000 feet, and in the Mojave Desert. In these areas, minimum relative humidity values are expected between 15 and 25 percent each afternoon while the pattern persists. However, the release of moisture from the soils in the Central Valley each night will allow for increased saturation along the surface, resulting in higher humidities each day. Minimums are expected near 40 percent, though maximum humidities will be 90 to 100 percent. Once again, with much of the surface air trapped under the ridge and the local terrain, this moisture has few avenues to escape. This will result in potential for fog development each morning, especially in the more rural areas where soils can more easily release their moisture.

As next weekend approaches, the is favorable agreement in the forecast model ensembles for a pair of low pressure systems to pass through the region. The first will be a relatively weak disturbance that is favored to track towards southern California. Moisture will gradually push northward, however there is a 20 to 30 percent probability for measurable (>0.01") rainfall to occur on Friday. These probabilities hold true for Saturday in the southern portions of the region, but increase to 40 to 50 percent in the Sierra Nevada and northern San Joaquin Valley. However, as the weekend progresses, a deeper trough will be aligned along the Pacific Coast which will push more moisture into the region from the south. For Sunday, there is a 60 to 70 percent probability for a wetting rainfall (>0.10") to be observed for the majority of central California. This second system is anticipated to be colder than the first, with snow levels falling to around 6,000 feet. In the Sierra above these levels, there is a 60 to 70 percent probability for at least 6 inches of snowfall over the 48 hours of the weekend.

AVIATION

While stations remain in VFR to MVFR across the Valley, dense fog may still form starting from 13Z through 18Z Sunday from just north of Delano through Merced County. For the Sierra Nevada and Mojave Desert, VFR conditions will be present for the next 24 hours.

AIR QUALITY ISSUES

ISSUED: 11/07/2026 14:42 EXPIRES: 11/08/2026 23:59

On Sunday November 8 2026, Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno, Kern, Kings, Madera, Merced, and Tulare Counties. Burning Discouraged in Kern (Greater Frazier Park Area) and Sequoia National Park and Forest.

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

Dense Fog Advisory until 10 AM PST this morning for CAZ302-306- 310>312.