Unsettled weather continues across Northwest US this week; rain and snow for California midweek
The barrage of storms will continue across the northwestern U.S. this week which means more rain, wind and snow for places.
The region has already seen some very gusty winds over the past 24 hours, especially near the coast and in the mountains. An area of low pressure rapidly deepened just offshore of Vancouver Island last night and the tight pressure gradient is bringing a strong onshore wind across the Northwest.
Rain and snow showers were also occurring across Washington, Oregon, northern Idaho, and northern California and these will continue through tonight. Snow levels across the Cascades are generally around 4,500 feet and will lower slightly tonight.
Another low pressure system is set to dive southward along the British Columbia coast and into the Northwest Tuesday through Thursday. This will bring another round of rain, cold air and mountain snow to the region. This one will likely be more significant.
Another strong low pressure system will deliver more cold air, rain and snow to the Northwest and also California at midweek.
The Cascades will continue piling up the snow. Snow levels will drop the lowest Wednesday night and Thursday when the coldest air arrives, likely falling to 2,500 to 3,000 feet. Through Thursday night, 1 to 2 feet of fresh snow is expected in the Cascades. The highest peaks could see up to 2.5 feet. For the I-5 corridor and coastal locations, steady rain, some heavy at times, are expected over the next few days.
This storm system will tap into some moisture from the tropics and this plume will be aimed at northern and central California Wednesday and Thursday. There will be a threat for heavy rain and flooding in the foothills and very heavy snow in the Sierra during this time.
Precipitable water shows a tropical moisture connection with the storm system at midweek. This will help fuel heavy rain and snow across the reigon, in particular across the Sierra.
Snow levels look to be around 7,500 to 8,000 feet in the northern Sierra Wednesday but will fall to around 5,500 feet on Thursday as the colder air dips farther south. Some snow and slippery travel is expected for Donner Pass.
The plume of moisture will be pressed farther south Thursday and Thursday night and may bring some rain into Los Angeles, especially at night.
Models show a ridge temporarily building in across the West Friday so the region will get a break from precipitation. High pressure is forecast to build at the surface across the Great Basin which will drive a moderate offshore flow across California.
Models show high pressure temporarily building in across the Great Basin and Rockies at the end of the week. This should drive an offshore flow across California.