Warmth and Rain Brings Flooding to the Pacific Northwest

After a very wet February, we have had a soggy March, which accompanied by warmth and snowmelt, is causing some of our rivers to surge.   During the past week, much of Washington, NW Oregon, northern Idaho, and Montana have experienced 200-600% of normal precipitation (see below).  In contrast, California and the southwest have been dry.

 Here are the precipitation totals for the past week from the National Weather Service analysis:  5-10 inches in the coastal mountains (including the Olympics) and the Cascades, with 2-6 inches over the western slopes of the Rockies.

But that is not all.  A week ago we had a normal snowpack, with substantial snow at lower elevations east of the Cascade crest.   But then the atmospheric circulation shifted so that warmer air flooded the region from the southwest.  As an illustration, the observed and typical temperatures for Spokane Airport are shown below.  Several recent days surged well above normal.

With lots of rain and substantial snow melt, water has been pouring into local rivers.   Here is the latest map from the NOAA/NWS Portland River Forecast Center.  Several western WA/Oregon rivers are at bankfull or flood stage, and notice that the Spokane river and some other draining off the Rockies are also at flood stage.

And it is not over yet.  Here is the NWS GFS model total precipitation forecast for the next 7 days.  Lots of rain over the Northwest (5-10 inches in the mountains).

There are going to be a lot of very happy ducks.