A Summertime Atmospheric River Will Reach the Northwest Tomorrow

 The coastal radar is already picking up the incoming rain offshore (see below).

Impressively, the UW modeling system shows a moderate atmospheric river heading for our coast at 5 PM today.

And the San Diego Atmospheric River (AR) center at Scripps is forecasting AR-1 conditions on our coast!

Note scared yet? 

You will be.

Below is the predicted total rainfall through 5 AM Thursday.  Wow.

All of western Washington is soaked and large portions of northeastern WA gets thoroughly wetted down.   

Some locations on the western side of the Cascades will receive 1.5- 2 inches.  That is a LOT for this time of the year.    Importantly, the Olympics will get enough to slow the Bear Gulch fire.

What about time and uncertainty?   The best tool for this is to look at the UW ensemble forecasts from many model runs (below) for Seattle.

All the forecasts are going for rain, with the wet fun starting around 3 AM and continuing into early or mid-afternoon tomorrow (Wednesday).

The mean total for the entire event in Seattle is about 0.4 inches.

Folks...this is unusual.  

Below are the record precipitation totals for August 6 at Seattle.   It is quite possible that tomorrow could be the third wettest August 6th on record at that location.

You will tell your grandchildren about it someday. 😀  And yes, you better find that umbrella.