Significant holiday travel impacts due to multiple winter storms through the weekend

Cold nights with Valley fog and frost continue into tomorrow. Rain and snow chances return early this week, becoming widespread by early Tuesday. A series of storms will continue this threat through the week into the holiday weekend with little break in precipitation expected. Mountain travel will likely be significantly impacted at times by moderate to heavy snow. Periods of gusty winds are also possible across the area.

Discussion

Some patches of fog this morning in the valley otherwise the low clouds seem to be preventing any widespread fog from forming. Another cold day in store for the valley with highs only expected in the upper 40s but at least a little warmer than yesterday. The focus will shift Tuesday afternoon to an incoming storm. The system has slowed down a little so have adjusted the timing back a little with rain/snow now forecast to move along the coastal range Tuesday afternoon and then spread to the western slope Tuesday night.

Dry air in place with low dewpoints will likely bring snow down to lower levels, possibly down to 3500 feet over parts of Shasta County and 4500 feet for the western slopes of the Sierra Nevada.

The initial rain/snow on Tuesday is expected to be light but increase in intensity on Wednesday. We will likely need a Winter Weather Advisory for this time period for the mountains.

Warmer and moist air will move over the region Wednesday night to help raise snow levels some before lowering Thursday and Thursday night. More significant rain/snow is expected to arrive on Thursday and Thursday night with lower snow levels expected.

Wednesday night or Thursday depending on location is when the heavier snows will start and travel conditions will deteriorate significantly.

Extended Discussion (Friday through Monday)

Four different waves of precipitation are forecast to move through during the extended period, one each day. A trough will remain over the west coast with shortwaves developing along the upper backside of the trough and rotating into the region. Each one of these waves will have the potential to bring significant rainfall to the interior.

Snow levels lower on Friday down to 1500 to 2500 feet. While snow levels may fluctuate at times in general expect low snow levels to remain through the weekend and a potential for significant snow down into the motherlode and over I-5 north of Redding.