February 18, 2024 – Moderate to heavy mountain snow, gusty winds, and isolated thunderstorms at times into early next week. Monday afternoon and evening brings elevated chances for thunderstorm development. Heaviest precipitation tonight through Monday morning.

Severe thunderstorms are possible over the Sacramento and northern San Joaquin Valleys. Monday from 12pm to 8pm. Threats include brief tornados, large amounts of small hail, heavy rain, lightning, gusty winds
Severe thunderstorms are possible over the Sacramento and northern San Joaquin Valleys. Monday from 12pm to 8pm. Threats include brief tornados, large amounts of small hail, heavy rain, lightning, gusty winds

Discussion

Conditions have quieted early this afternoon with a lull before our next round of weather impacts begin later this afternoon and continues into Wednesday morning.

We're expecting gusty southerly winds this afternoon with the strongest winds expected across the Sacramento Valley and surrounding mountains. Secure outdoor items.

Southerly winds increase this afternoon with gusts of 40-50 MPH possible in the Central Valley and foothills, tapering off Monday morning. A Wind Advisory is in place from 4 PM today until 4 AM Monday. Another round of winds are expected late Monday morning into the evening hours, strongest in the northeast foothills with 45-60 MPH gusts possible.

Rainfall forecast through Wednesday. Moderate impacts are expected from widespread rain. Be prepared for slick driving conditions and give yourself extra time to reach your destination. Periods of moderate to heavy precipitation may lead to roadway ponding, minor flooding or urban and poor drainage areas.

Rain will move into the Valley this afternoon with periods of moderate to heavy rainfall through Tuesday. Heaviest precipitation will be this afternoon and evening, outside of localized areas of heavy rain from thunderstorms. Probabilities of 2 inches or greater in the Valley are 40-80% from Sacramento to Redding with higher chances as you move northward in the Valley. The Northern Sacramento Valley and Coastal Range areas should expect more rainfall with a 60-90% chance of seeing amounts 3 inches or greater.

Periods of moderate to locally heavy rain may lead to roadway ponding and minor flooding of urban and poor drainage areas, creating difficult commute conditions and slick roads

With the threat of some pockets of rain rates of 0.50″/hr and heavy showers from thunderstorm development, a FloodWatch continues to be in effect through Wednesday morning as some minor flooding issues are possible.

Winter storm warning

Snow over the Sierra will increase again this evening and continue through Wednesday morning, heaviest early Monday morning. Latest HREF shows snow rates of 1-3″/hr possible along the I-80 and Hwy. 50 corridor early Monday morning with winds as high as 55 MPH.

Snow forecast. Major Impacts. Snow amounts generally range from 18 to 24 inches above 6000 feet, up to 3+ feet over peaks. Impacts: major. Chain controls and road closures. Significant reduction in visibility with whiteout condition at times. Snow levels: 5000’ to 6000’. Timing: Sunday PM, February 18 – Tuesday, February 20, 2024

Travel conditions will be difficult with chain controls and road closures expected.

Winter storm impacts - major

A Winter Storm Warning is in effect through 10 AM Wednesday, so please check the latest travel conditions before attempting any mountain travel.

What's the difference between a Tornado verses a Funnel Cloud. Funnel Clouds are observed in the atmosphere while Tornado's extend to touch the ground resulting in damage at the surface.
What’s the difference between a Tornado verses a Funnel Cloud. Funnel Clouds are observed in the atmosphere while Tornado’s extend to touch the ground resulting in damage at the surface.

Isolated thunderstorms are possible each afternoon and evening through Tuesday with NBM probabilities and EFI (Extreme Forecast Index) values highlighting thunderstorm development (20-30% chance Sunday) Monday afternoon looks to be most promising with with the combination of favorable shear profiles and adequate amounts of lift to producing severe thunderstorms and even brief, weak tornadoes. Similar setups in the past have resulted in a few brief tornadoes with efficient small hailers.

Residents in the area (Yuba City, Sacramento, Stockton, and Modesto) are advised to pay close attention to the Monday forecast.

Conditions quiet on Wednesday as drier and mild weather returns for the end of the work week. Temperatures looks to warm a few degrees, reaching into the low to mid 60s in the Valley by Friday.

Extended Discussion (Thursday through Sunday)

Cluster analysis depicts an area of upper-level ridging moving over our area Thursday and sticking around through Friday. Dry weather and a gradual warming trend will dominate this period before an upper-level low moves into the region late Saturday.

Looking at the National Blend of Models (NBM), there is a 20-50% chance of 0.25″ or more in the Valley/foothills with a 10-30% chance of high-elevation snowfall 1.00″+. That being said, there is still uncertainty this far out with the NBM 48-hour QPF 10th percentile showing little to no precipitation over the weekend and the 50th percentile indicating under 0.10″ in precipitation for the Valley.

Beyond the extended period, ensembles indicate the potential for another system early next week. Nevertheless, keep checking back for updates as we learn more in the coming days!