Today, I will mix it up a bit and go away from the closed low and the rain it will bring to Southern California by Thursday. Today, I will look on the other end of the spectrum, the exceptionally dry conditions in the Northwest.
It is not unusual to be dry for two and a half months in California for the summer into early fall. In fact, it is pretty normal. But the Pacific Northwest? This is an area of the nation that many people think is a pretty rainy place. Some of this is true; some of it is an overstatement. But in reality it does rain in this area fairly often, especially from the Cascades on west.
But since the beginning of August, even a few raindrops have been hard to come by. Below is a table showing some of the major cities along with how much rain has fallen since Aug. 1, what is normal during that time period and what percentage of normal rain has fallen.
These rainfall amounts are more like what one would expect in a desert region. All cities have had an extremely small percent of what is normal during this time, and a couple of places have had no rain at all. These are incredible numbers for this part of the country.
The weather is going to stay bone dry for another two days before changes finally take place. Rain will return to areas west of the Cascades on Friday as a cold front arrives. A second front will move in on Saturday. East of the Cascades, the first front will be mainly dry, but a couple of showers seems likely with the second front. And it looks wetter right on into next week with potentially for some pretty good rain amounts in parts of western Washington early next week.
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.