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 Saturday morning.

2. Above average temperatures and low relative humidities expected through the weekend, the latter especially in the Sierra Nevada.

3. Precipitation chances return next weekend.

DISCUSSION

The main topic of discussion over the last few days has been the return of the fog here in the Central Valley after last weekend's rainfall. The story looks to continue for at least another day, as there are moderate chances (30 to 50 percent) for visibilities of one quarter mile or less, mainly in the region from Delano to the rural areas just south of Fresno, and includes the cities of Kingsburg, Selma, Visalia, and Hanford. The residual nature of the fog is due in large part to the amount of moisture still being held in the local soils that condenses just above the surface overnight as temperatures cool. This effect is usually enhanced by clear skies, as has been the case this past week; cloudy conditions act as an insulating layer, warming surface temperatures which result in less saturated air. In addition, the presence of a high pressure ridge has created a subsidence inversion, acting as a lid on low level air trying to escape the valley, but is unable due to the local mountain ranges.

The high pressure is also having the effect of warming temperatures across the region this weekend, which will approach eight to ten degrees above season averages. The above- normal temperatures and lack of residual moisture above the Sierra Foothills means that much drier air will also be present. In the Sierra, mainly above 4,000 feet, minimum relative humidity values are expected to be between fifteen and twenty five percent for much of the upcoming week, though cooler overnight lows will cause moderate recoveries between forty and sixty percent.

Relative humidities are favored to improve towards the end of next week, coinciding with a low pressure trough dropping out of the North Pacific. While upwards of a week out, forecast ensemble guidance points towards a 20 to 30 percent probability of one-tenth or more of rainfall in the San Joaquin Valley Friday, with greater probabilities of 40 to 50 percent in the central Sierra Nevada. Naturally, with the trough tracking south from colder regions, there is also a 40 to 50 percent probability for at least one inch of snowfall in the upper Sierra.

AVIATION

MVFR conditions exist in most of the Valley and is expected to continue through the nighttime hours, while KVIS and KHJO are seeing visibilities bouncing between IFR and LIFR, which is also expected to continue through the night into at least 18Z. For the Sierra Nevada and Mojave Desert, VFR conditions will be present for the next 24 hours, and in the San Joaquin Valley after 18Z Sat.

AIR QUALITY ISSUES

ISSUED: 11/06/2026 15:35 EXPIRES: 11/07/2026 23:59

On Saturday November 7 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 CAZ306- 310>312.