February 16, 2024 – Quiet weather anticipated through midday Friday. Afterwards, widespread Valley and foothills rain and high elevation snow is expected with heaviest precipitation expected late Sunday into Monday.
Discussion
One more day of quiet weather as ridging slides over the forecast area today. There is the chance for areas of fog across the Northern San Joaquin and Southern Sacramento Valleys this morning, so please exercise caution on your morning commute. HREF probabilities have a 40-70% chance of visibility lowering than an half mile, lowering after 10 AM. Afternoon highs today will be in the upper 50s in the Valley and low 50s and 40s in the foothills and mountains.
Our pattern shifts on Friday as a trough develops in the Pacific and moves northeastward over our forecast area. The first wave of precipitation will move into the western portions of the Valley late Friday morning with higher elevation snow beginning Friday afternoon and evening and continue through Saturday.
For the Valley, heaviest precipitation rates will be Friday afternoon and night and in the mountains, Saturday morning. QPF totals in the Valley will be around 0.50-1.00″ with 1.00-3.00″ in the mountains, highest in the Northern Sacramento Valley/Coastal Range and Feather River Valley area. Probabilities of over an inch in the Valley from Sacramento through Red Bluff is 30-60% increasing as you move northward and for over 2 inches in the mountains, probabilities are 40-80%.
Snow levels will be generally above 6500 feet with over a foot expected at higher elevations. At elevations above 6500 feet, probabilities of 12 inches or more are 25-50% along and north of I-80 and 30-55% south of Hwy. 50.
There will be some breezy south to west winds in the mountains on Saturday 25 to 35 MPH. Rain and snow rates decrease early Sunday morning, although most places will be still under active precipitation.
A stronger push of moisture on Sunday will continue active weather in our area into early next week, repeating the pattern of starting off along the west side of the Valley and in the mountains then filling into the Valley and down the Sierra.
This will be the heavier of the two waves with the potential of moderate to heavy periods of rainfall in the Valley with 1-2 feet of snow accumulation in the mountains. QPF totals are 1.25-2.50″ in the Valley and 2.50-4.00″ in the mountains with up to 5 inches in the Feather River Valley.
This continues to be a warm system and snow levels increase 6500-7500 feet by Sunday night but return to 6000-7000 feet early next week. Above 7000 feet, probabilities for over 8 inches north of I-80 are 40-60% and 45-95% south of Hwy. 50.
Additionally, south winds increase on Sunday in the Valley with gusts 20 to 30 MPH expected. Active weather continues into early next week with Monday being the heavier of the two days. If you are planning weekend travel, please continue to monitor the latest forecast and take travel precautions!
Extended Discussion (Monday through Thursday)
Ensembles and clusters indicate that stormy pattern over the eastern Pacific for the first part of next week. The back end of the strongest storm will be moving though early Monday morning.
This is a period with an increase in the potential for ponding of water on roadways, flooding of low lying areas, increased stream levels and flows, mud and rock slides.
Snow levels continue to be high between 6500 and 7000 feet. The storm will gradually taper off to showers by mid to late morning into the afternoon hours and gradually diminish late Monday night.
Zonal flow is forecast over the area Tuesday night and Wednesday when a weak system is indicated by the various models and ensembles to move through the region. Snow levels continue to be high at around 6000 feet and to impactful.
This system looks to bring generally around a half inch for the valley, less in the San Joaquin valley to an inch or more around Redding. Probabilities of at least half an inch of rain range from 5-10% over the San Joaquin Valley to 25-35% Sacramento area to 40-75% central and Northern Sac Valley. Mountains range from 25% in the south to 60-80% north of I-80.
A ridge will build over the region on Thursday to bring dry weather. Mild high and low temperatures are expected though the expected period.