The only story in the West of big importance weather-wise is the impending chance of rain next week over much of California. An early season closed low will bring the chance of some rain for much of central and Southern California for at least several days next week along with temperatures well-below normal.
The ideas remain the same from my two previous posts. I am not going to rehash what I have been saying. I do want to give you a visual look at each day Monday through Thursday next week to show you the stability of the REX block. Because we cannot redistribute the European model data in graphical form, and the fact that there really is no important large-scale differences between it and the GFS, I give you the 500 mb graphics from the 12Z run of the GFS for each day.
As with any closed low where precipitation occurs, it is very hard to forecast even a day or two out. It is obvious that there is a good chance for scattered showers, and even a thundershower, somewhere around this closed low each day. It is also likely in this pattern that temperatures will stay well below normal for some time to come.
These is the possibility that another surge of tropical moisture could move into Arizona and Southern California by the middle of next week.
I still believe the greatest amount of rain, at least partially relating to Norbert, occurs from southeast California to Arizona
The effects on Southern California are very much in question.
With low wind shear and warm water in its path for a while longer, it is likely that Norbert intensifies into at least a Category 2 storm.
For much of the last week the monsoon moisture flow into the Southwest has been completely shut down by dry westerly winds. This is about to change.
A big pattern change is underway, one that will completely shut down any chance of showers and thunderstorms for an extended time period.