The Tale of Two Troughs

 The rain has begun in earnest tonight as shown by the radar at 10 pm (below).

It will rain much of this week and the totals will be impressive by the time it is over, with some sodden locations getting 10 inches or more.

The key features bringing the rain are two upper-level troughs of low pressure. The next figures show the upper-level maps this week (500 hPa pressure, about 18,000 ft above sea level).

The first trough is moving in right now (see map at 7AM Monday)

On Tuesday, a weak ridge of high pressure moves over us, providing a break.

And then a strong trough comes in on Wednesday (see below).  Classic November pattern.

Now let me show you the precipitation totals.

Through Monday at 4 PM, some healthy totals, with up to 3 inches in the mountains.

A bit more by Tuesday at  4 PM

But by Wednesday at 4 PM..wow.  Much more, with some locations up to 10 inches.  And it is not over.

Freezing levels will be high enough today to limit snow accumulation, but later in the week it will get cool enough to bring substantial snow totals above 4000 ft.  The snowfall total through Thursday at 4 PM is shown below, with the north Cascades getting several feet.  Snoqualmie is too low and warm to get much.

Mid-November and the atmosphere is doing what it should. Our water resources are being restored, reservoirs are refilling, and moisture is percolating down into our soils.