The weather pattern along the West coast from Washington state to California is very dull. In general, there is a ridge of high pressure at 500 mb in control.
This high is providing warm temperatures away from the immediate beaches but not excessively hot weather as we had in portions of Southern California late last week and over the weekend. Temperatures will be averaging above normal.
There is a broad and relatively weak, closed low well west of the southern Oregon/northern California coast. While this spins well offshore the next couple of days, it will eventually head east by Friday and the weekend. Models are in agreement on this. What they are not in agreement on is how far south the low will go. The main effect on the weather would be on how much cooler air occurs, especially in central and Southern California. Precipitation is not going to be much, though there could be a mainly afternoon shower or thundershower in a few spots over Oregon, northern California and northern Nevada. Monsoon moisture is not going to be a player.
A rather extended period of unsettled weather will be occurring over parts of California and the Southwest
The remainder of the week a large building ridge of high pressure takes over
There will be more showers and thunderstorms are likely that can produce very heavy downpours in Arizona.
This rain caused problems with flash flooding producing some damage and there were a few swift water rescues.
Computer models are insistent that a rather strong piece of energy will move through California Tuesday, bringing more widespread rainfall.