textproduct: San Joaquin Valley

UPDATE

Updated for Key Messages and 12Z Aviation.

KEY MESSAGES

1. Multiple storms move through the region through Thursday, bringing periods of moderate to locally heavy rain and snow.

2. Winter Storm Warnings in effect for the Sierra Nevada until Thursday evening and the Kern County mountains through Friday morning, including the I-5/Grapevine area.

3. Strong winds will increase the risk for power outages, downed trees, and road hazards for many mountain areas as well as the Mojave Desert and the southern San Joaquin Valley.

DISCUSSION

The core of a cold low pressure system will continue sweeping through the northern half of California tonight. The fringes of a very strong jet will bring strong southwest winds over the mountains, with some of that energy mixing down to the valleys. With precipitable water readings just under one inch, this flow will couple with cold unstable air aloft to bring widespread moderate rain and mountain snow, with some pockets of heavier precipitation. Snow levels will continue falling below 3,000 feet tonight into Wednesday morning, before precipitation exits the region. Most areas will see a break on Wednesday, except for a few lingering showers over the northern Sierras. That break will be brief as another storm system will move through on Thursday. This system will likely bring another round of gusty winds, moderate rain and mountain snow, and maybe a thunderstorm, just a step down in severity compared to tonight.

The most significant impacts with these two storms this week is with snow. Several feet of additional snow is likely over elevations of 5,000 feet. For lower mountain elevations, snow accumulations will be less but still impactful as there is a moderate risk for a few inches on the Grapevine/Tejon Pass and Tehachapi Pass. Winter Storm Warnings continue.

Friday and Saturday will bring a break in the storms, but nights will be cold and some fog concerns exist. Another round of storms is on target for next week starting Sunday.

AVIATION

Precipitation will continue in the San Joaquin Valley until 16z Wednesday, then a gradual reduction in rain across the Valley. A 5-15% chance of TSTM from 18Z Wednesday to 03Z Thursday towards KMCE and the coastal ranges. IFR/LIFR conditions in the Sierra Nevada due to moderate to heavy snow. Surface winds generally 12 kts and below at the TAF sites, but winds 20-30 kts with gusts 35-45 kts continue in the mountains and desert until 00Z Thursday.

AIR QUALITY ISSUES

On Wednesday February 18 2026, Fireplace/Wood Stove Burning Status is: Burning Discouraged in Fresno, Kern, Kings, Madera, Merced, and Tulare Counties, and 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

Wind Advisory until 4 PM PST this afternoon for CAZ300-308-313- 337>339. Winter Storm Warning until 10 PM PST Thursday for CAZ318-320- 322>331. Winter Storm Warning until 7 AM PST Friday for CAZ333>336.