Fall Fronts update

After a couple of dry cold fronts over the past few days, we are going to get some rain from the next weather system.  The difference is that this storm will center itself right over eastern Washington on Wednesday.  You can see the center of the low on the anomaly chart below.

Winds rotate around a low in a counter-clockwise direction.  So instead of the Cascades providing their usual rain shadow (if the wind was from the west), in this case they don't play that role because the wind will be coming from the east and north.

A cold upper low like that should also create an unstable atmosphere.  Showers and a few thunderstorms will spiral around the low center on Wednesday.  Here's what one computer model thinks the radar will look like on Wednesday afternoon.

All of this activity will slowly drift to the southeast, exiting the Inland NW on Thursday.  The computers all differ on the exact amounts of rainfall they expect, which is normal.  They generally agree that southeast Washington will likely see the most rainfall.

By Sunday, this low will be out in the northern Plains states.  By then a much larger and deeper area of low pressure will develop off the West Coast. 

This pattern will initially bring some warmer air into the Northwest, with temperatures back into the 70s.  But it will also likely send some wet fronts through our area next week.  Timing of them is pretty much impossible at this point, but right now it appears that Tuesday or Wednesday of next week would have the best chance for rain.  These wouldn't be really wet storms.  Probably something on the order of a tenth of an inch.