Next round of precipitation arrives this afternoon into Tuesday night. Periods of moderate mountain snow and light rain showers are anticipated with this system, mainly from I-80 northward. Dry weather returns mid to late week.
Discussion – today through Thursday.
Key points Today-Tuesday:
- Another system will bring additional precipitation later this afternoon through Tuesday night. 6-12″ of additional snowfall will be possible above 4000 feet this afternoon through Tuesday from I-80 northward; locally to 2 feet over peaks. Winds gusting up to 40 mph later today into Tuesday over the Sierra may result in additional impacts as well.
- Periods of moderate mountain travel impacts expected through Tuesday night.
Current radar imagery shows a few lingering snow showers over the Sierra early this morning, with snow levels around 3500 feet. Observed precipitation totals over the last 24 hours have ranged from 0.25-1″ over the mountains, with 0.25-0.50″ over the foothills.
Elsewhere, near freezing temperatures may be observed across the northern Sacramento Valley this morning, with the NBM indicating a 30 to 70% chance of low temperatures reaching 32F. Hi-Res models indicate some light snow showers persisting through this morning before the next round of moderate snow arrives later this afternoon.
WPC guidance indicates 0.25-1″+ of precipitation over the foothills and mountains, with generally less than 0.10-0.20″ in the northern and central Sacramento Valley (locally higher amounts in the northern Sacramento Valley).
Snow levels for this additional system look to sit around 3000 to 4000 feet Monday evening and overnight, before rising to 4000 to 5500 feet by Tuesday. With the drier air working into NorCal as the upper low moves further inland, available moisture for additional snowfall will be limited. The best chances for accumulating snow will be from Highway 50 northward. Total snow accumulations of 6 to 12 inches, locally up to 2 feet at highest peaks, are forecast for Western Plumas County/Lassen Park through Tuesday.
NBM depicts a 40-80% probability of at least 6 inches of snow from I-80 northward.
A Winter Storm Warning remains in effect from 10 AM PST Monday through 4 AM PST Wednesday for the mountains from Highway 50 northward. Gusty southerly winds will increase with this system later today into Tuesday, with gusts up to 40 mph over the Sierra.
Light mountain snow showers may linger through Wednesday as a separate closed low approaches SoCal, but overall significantly lesser impacts are anticipated.
In fact, the approaching closed low will likely accelerate a warm up for interior NorCal, with high temperatures rebounding to near normal by Wednesday afternoon.
Extended Discussion (Friday through Monday)
A ridge of high pressure will be over the region on Friday with northerly winds over the valley and easterly winds for the Sierra Nevada. Winds are not expected to be that strong with only local breezy winds expected. Temperatures warming into mainly the mid 60s for the valley to the mid 40s to mid 50s in the mountains. Models and clusters are indicating a change in the weather pattern next Saturday for the potential of some more wet weather. This system does not look that strong and should only have minimal impacts. The system moves through fairly quick and next Sunday should be mostly dry ahead of another system currently due to start to spread into the interior late Sunday night and Monday.