A combination of two separate storms will bring much of the West a round of wet, cool weather for Wednesday into Thursday.
The first storm is located west of California and is cut off from the overall jet stream. This low is about at 35N and 135W on the satellite picture below.
The second storm is just off the picture in the western Aleutians and Bearing Sea and will move southeast across the Gulf of Alaska and north Pacific the next couple of days. The southern low is still headed south and that motion continues tonight before stalling, and then moving east slowly Tuesday night through Thursday. The track of that low takes the greatest amount of energy across Southern California late Wednesday into Thursday morning. The northern storm spreads rain into the western Northwest Wednesday with the southern end of the rain filling in the gap the southern storm left across northern and central California. The interior Northwest and into Idaho and Utah has the greatest amount of precipitation late Wednesday night and Thursday. Meanwhile in the south, the rain will tend to end in most places in California by Thursday afternoon. Farther east, even Arizona will see some precipitation late Wednesday night and Thursday.
Snow will fall but snow levels will not be especially low, generally in the 6,000 foot range or slightly above in the Sierra and a little higher than that in the Arizona Mountains. Snow will also fall in the Cascades, but roads through the passes should be okay.
With such high amounts of water vapor, thunderstorms will bring locally very heavy rain that can cause flash flooding.
Many areas east of the Cascades this weekend will be over 100 F.
some of the moisture from Andres and newly formed Blanca could influence the weather in the Southwest
A powerful second punch is offshore right now and comes inland during the early morning hours. It will bring moderate to heavy rain for the Friday morning rush.
The main storm will move in off the Pacific Thursday and Friday.
Last year by the end of April the drought in California was very bad. Since then it has become even worse.