Showers and a few thunderstorms will continue across the region today before tapering off from the north on Tuesday. A brief period of dry weather is expected mid-week before precipitation returns by the end of the week.
Discussion
After a brief break Sunday evening, radar indicates showers are spreading back inland across NorCal as the closed low off the coast edges closer to northwest California with rain already observed at Redding and Red Bluff. Rain will likely return to the Sacramento area during the morning commute, and snow will pick up after sunrise across the northern Sierra.
Southerly surface pressure gradient is increasing again ahead of the low, and a few gusts of 20-25 mph will be possible in the Sacramento Valley today. Several lines of showers and thunderstorms are expected across the region today as the mid/upper trough moves ashore.
In between the lines of showers, surface heating is likely to occur with valley highs likely to reach the mid 50s to lower 60s resulting moderate instability similar to Sunday. Forecast soundings indicate quite a bit of low/mid-level shear, so would not be surprised to see a funnel cloud report with longer-lived cells. Main threat will be occasional lightning, small hail and brief heavy rain.
Snow will pick up in the Sierra again today, but amounts are likely to considerably lighter than the weekend. Nevertheless, another 8-12 inches will be likely above 5000 feet resulting in continuing significant travel impacts.
The trough finally shifts south on Tuesday with showers tapering from the north during the day. A brief period of dry weather is expected Wednesday into early Thursday which will allow for a couple cold mornings in the valley with minimum temperatures around the freezing mark in the outlying areas (especially Wednesday morning) with widespread frost and patchy fog.
Extended Discussion (Friday through Monday)
Long wave trough continues along the West Coast with series of short waves pushing through during the extended forecast period.
Front progged through early Friday followed by a secondary wave Friday night into Saturday.
Forecast confidence lowers late weekend into early next week as deterministic model and ensemble solutions diverge with large cluster analysis variation. Below normal high temperatures expected through the extended period.