textproduct: San Joaquin Valley

KEY MESSAGES

1. Storm system continues through this afternoon with continued rain showers and mountain snow.

2. A Winter Storm Warning for the Sierra Nevada above 6,000 feet remains in effect through 10 AM PST today. A Flood Watch continues for the Sierra and adjacent foothills below 6,000 feet through 4 PM this afternoon.

3. Unsettled weather with mainly light precipitation remains Monday afternoon through Thursday, then there is a moderate chance of Tule fog to return to the Central Valley Thursday night.

DISCUSSION

A few light showers remain in our forecast area, per latest radar data. Additional light to moderate showers will pass over the region through the afternoon hours, although there is a bit of uncertainty as latest high resolution guidance has been showing a band of robust moisture that may end up passing over the coast and to our north. For now, will keep the Flood Watch in effect, as the probabilities of at least another 0.50 inch in the foothills remains at 50-60 percent. It won't take much additional rainfall to produce at least some minor impacts. We will also keep the Winter Storm Warning in effect through late morning for the Sierra Nevada at this time.

From this afternoon forward to Thursday, we will continue to see remnant moisture and additional disturbances. The main upper- level low will track offshore to the south and end up near northern Baja California before it moves inland. Mainly light showers will occur during this period, as the probability of just 0.10 inch per every 24 hours (ending each afternoon from Tuesday-Thursday) drops to 20-30 percent at the most. Cool temperatures and at least partly cloudy skies will prevail across the region during that period. On Thursday, before the upper-level ridge sets up, an inside-slider upper-level shortwave trough passes over Northern CA to the Great Basin. This may produce additional light showers in the Sierra Nevada, with the best chances towards Yosemite (20-30 percent chance), as well as increased winds to the Sierra crest and to the Mojave Desert slopes. For now, ensemble guidance suggests a low to moderate probability (about 25-35 percent) of 40 mph gusts.

For Friday into next weekend, the ridge of high pressure builds over the Western U.S. and persists for several days. The Climate Prediction Center's Outlooks shows a 50-60 percent chance of below average precipitation for the 6-10 day period, and 40-50 percent at 8-14 days ahead. Above average temepratures remain favored (50-60 percent for both periods).

AVIATION

Expect MVFR/IFR conditions at the TAF sites and much of the forecast area at times through the next 24 hours due to clouds and showers. Otherwise, VFR conditions will prevail for the next 24 hours. A 5-15 percent chance of IFR will exist 11Z-17Z Monday.

AIR QUALITY ISSUES

On Monday January 5 2026, Fireplace/Wood Stove Burning Status is: Burning Discouraged in Fresno, Kern, Kings, Madera, Merced, and Tulare Counties, and in Kern (Greater Frazier Park Area) and Sequoia National Park and Forest.

CERTAINTY

The level of certainty for days 1 and 2 is medium. 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

Flood Watch through Monday afternoon for CAZ317>322-324-325. Winter Storm Warning until 10 AM PST Monday for CAZ323-326>331.