Some big changes will take place from the weather experienced today to the weather by the weekend and early next week up and down the West Coast.
In central and Southern California and the Southwest, the above-normal temperatures, and in some areas just plain old hot weather, of late will be going about a bit of a cooling process. By the weekend, temperatures will be near normal in the Desert Southwest but below normal for coastal and coastal valley areas. High temperatures by Saturday and Sunday in places like Los Angeles and San Diego will be 20-plus degrees lower than today. A return of morning low clouds is also likely in these areas. In the Central Valley, it won't be quite as dramatic but a good 10 to 15 degrees of cooling is likely.
In the Northwest, wetter, and in some areas whiter, weather is likely along with colder temperatures. A strong and cold upper-level trough will develop south of the Gulf of Alaska. This will eventually form a cold upper-level high off the Northwest coast early next week. This is likely to bring periods of rain west of the Cascades and some showers east along with a big drop-off in temperatures. Snow is likely to fall in the Cascades with snow levels dropping below pass level in Washington state by Sunday. Next week it's likely to get even chillier with even lower snow levels and additional showers or rain along with snow in the mountains.
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.