A "Perfect" Storm Hits the Northwest

If you were to order a "storm" for the Northwest, you would request one that drops lots of rain over the crest and eastern side of the Cascades, decisively ending the wildfire season and providing needed moisture to late-season crops.

To do so would require an upper-level low centered along the northern Oregon or southern Washington coast, which would swing moisture in from south into eastern Oregon and Washington.  

Exactly what is happening this weekend (see upper-level map for 2 PM Saturday).

Upper-level chart (500 hPa pressure level) for 2 PM Saturday. 

The resulting clouds swirling around the low are impressive:

As was the radar image last night.

Consider the  "storm" precipitation totals as of this morning around 6 AM (below).

Nearly an inch at some locations east of the Cascade crest as moist air swung around the low and rose on the eastern slope.

Looking forward, the total precipitation predicted through 5 AM Monday (by the UW WRF model) is quite impressive, with several inches forecast east of the Cascades, exactly where we need it to end the fire season

And believe it or not, it is cold enough aloft to result in some snow at higher elevations (see below)

We will have a warm/dry period this week, followed by the return to much heavier precipitation in ten days.  Welcome to autumn.