The strongest atmospheric river ever measured in the Gulf of Alaska? – Watts Up With That?

From the Cliff Mass Weather Blog

Cliff Mass

The atmospheric river currently flowing across the Gulf of Alaska may be the strongest ever recorded in that area.

The latest model runs show extreme values ​​of the key measure of atmospheric river strength, vertically integrated moisture transport (IVT)which indicates how much water vapor is moved during a certain time.

Below you can see this morning’s IVT map, with values ​​above 1900. I’ve personally never seen anything like it.

According to an estimate by Dr. Lexi Henny of NASA/Goddard, this is the strongest atmospheric river observed in the period 1990-2019. Impressive.

The plume of moisture was clearly visible on satellite water vapor images this afternoon (below). See the southwest-northeast directed plume toward SE Alaska and BC? Some of the associated clouds have moved into Washington.

This atmospheric river is predicted to make landfall as a AR-5the strongest level ever observed. We can be thankful that the middle of the river is making landfall north of Washington State, where only AR-2 levels should occur on the northern Olympic Coast.

About a foot of rain is expected to fall on British Columbia’s coastal area on Tuesday

At this time of year, strong atmospheric rivers are common in Southeast Alaska and British Columbia. In November, plumes of moisture reach Washington State.

The fact that we are in a neutral to La Niña year means there is a greater chance of more rain than last year (an El Niño year)…something shown below for the western Washington Lowlands.

My advice: make sure you have a good umbrella.

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