textproduct: San Joaquin Valley

UPDATE

Updated Aviation.

KEY MESSAGES

1. Flood Watch from 10pm Wednesday to 10pm Thursday for for the southern and eastern Kern county.

2. Gusty winds continue along the Grapevine in Kern County until Thursday morning.

3. Probability of 60-70% of 1 inch of rain in 48 hours through Friday in the mountain and desert portions of Kern County. Areas which received the heaviest rainfall last week will be the most vulnerable to flooding.

4. Winter Weather Advisory for Sierra Nevada above 6000 feet from Yosemite to Kings Canyon from early Saturday through early Sunday afternoon. Additional rain expected below 6000 feet, with higher amounts mainly Fresno County north.

5. Another band of precipitation arrives later Sunday afternoon and brings significant snow above 6000 feet for much of the Sierra Nevada, including to Tulare County. More widespread rain below 6000 feet, but lighter precipitation amounts over Kern County.

DISCUSSION

Rain showers associated with a closed low off the coast and an atmospheric river will continue to impact the region tonight through New Year's Day. Dense fog will continue to be an issue as well in the valley, and a Dense Fog Advisory remains in effect until late Thursday morning. Gusty winds will continue across the Grapevine overnight through early Thursday morning, with gusts up to 50 mph expected. A Wind Advisory remains in effect here until 15z Thursday.

Latest MRMS analysis shows about 0.10-0.25" of precipitation has fallen across the Flood Watch area of the southern and eastern Kern County deserts in the last 12 hours, and ensemble guidance shows a 30-50% chance of this area receiving another 0.50" by Thursday night. This will keep the risk of excessive precipitation in this region ongoing for New Year's Day. There is also a 10-15% chance of thunderstorms across here Thursday morning and afternoon, which could result in locally higher rainfall amounts if thunderstorms do occur.

Following the departure of this disturbance, a brief lull in precipitation is expected for the first part of the day on Friday. However, another coastal trough will direct waves of precipitation into the region beginning late Friday night and continuing through Tuesday. Latest ensemble guidance shows a 60-80% chance of 1" of precipitation falling across southern and eastern Kern County in the 72 hour period between 12z Saturday and 12z Tuesday, which could reintroduce concerns for excessive precipitation. In the Foothills, there will be a 40-70% chance of 1" of precipitation or more. In the highest elevations, these odds rise to near 100%.

While snow levels are around 8000-9000ft for the New Year's Day system, they will fall closer to 6000ft for this second system, which will result in elevated snowfall amounts in the higher elevations. Confidence has increased enough in snow impacts from the initial wave of this second system to issue a Winter Weather Advisory from 09z Saturday to 21z Sunday for areas of the Sierra Nevada above 6000 ft from Yosemite to Kings Canyon, with the anticipation of additional winter headlines likely being needed beyond Sunday with future forecast packages.

AVIATION

Rain will continue to push east with a few light rain showers hanging around MCE and MER until 00z. Partly to mostly cloudy skies will persist with all TAF sites sitting in VFR for the rest of today. Overnight, areas of shallow fog may form after 06z with light winds and clear skies. Ceilings could drop down to IFR/LIFR conditions and visibilities could drop below 1 SM if fog does form. Skies are expected to clear out after 15z Friday morning.

AIR QUALITY ISSUES

On Thursday January 1 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

Winter Weather Advisory from 1 AM Saturday to 1 PM PST Sunday for CAZ323-326>328.