The Atmospheric River Event is Ending--- And ANOTHER One is Predicted

The heavy rainfall is over, but some rivers are still rising.   The most impactful atmospheric river event of the past few decades.

Consider the 5-day rainfall totals below, and be prepared to be impressed.  

Many of the windward slopes of the Cascades and Olympics received more than 10 inches, with some experiencing 15-17 inches.

You will also notice extreme rain shadow areas in the lee (east) of major barriers, which received less than an inch.

Numerical weather prediction models were STUNNINGLY good, as shown by the predicted 5-day precipitation totals by the UW WRF model made last Sunday (see below).  

Close correspondence between predicted and observed rainfall.

The weather prediction world has changed dramatically during the past decades, with virtually every major extreme weather event predicted days before.

The problem is that governments, local agencies, and others are not sufficiently taking advantage of these skillful forecasts to save lives and property.  The media do not understand the profound impact of improved weather prediction technology.  

This problem is compounded by the National Weather Service, whose forecasts and warnings have declined substantially compared to the state of the art.  

 I can provide a half-dozen cases of the NWS failing to provide timely warnings even when model forecasts are excellent, such as this event and the Seattle ice storm of December 2022.

I hate to reveal this, but  ANOTHER significant atmospheric river/precipitation event is in the forecast.

Consider the predicted 72-h precipitation total ending 4 AM on Thursday.  Yikes...pretty wet, with some mountain areas getting 10 inches.  This is problematic, falling on saturated soils and rivers already well above normal.

To address the reliability of this forecast, one should consult ensembles of many forecasts.  Below are plots of forecast precipitation at Stampede Pass in the central Cascades from many forecasts.

All are going for a major precipitation event starting in the middle of next week.  You can take this to the bank.

All of this is a reminder that the most impactful severe weather of the Pacific Northwest is flooding.  Not heatwaves, not wildfires, not windstorms.