The atmospheric river currently over the Gulf of Alaska may be the strongest on record in that area.
The latest model runs show extreme values of the key measure of atmospheric river strength, vertically integrated moisture transport (IVT), which describes how much water vapor is being moved over a period of time.
Below is the map of IVT for this morning, with values exceeding 1900. I have personally never seen anything like it.
The plume of moisture was very apparent in water vapor satellite imagery this afternoon (below). Do you see the southwest-northeast directed plume aimed at SE Alaska and BC? Some of the associated clouds have moved into Washington.
This atmospheric river is predicted to hit land as an AR-5, the strongest level observed. We can be thankful that the center of the river will make landfall north of Washington State, where only AR-2 levels should occur on the northern Olympic Coast.
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By Tuesday, as much as a foot of rain will fall over the coastal terrain of BC
Strong atmospheric rivers are not infrequent over SE Alaska and BC this time of year, with the path of the moisture plumes reaching Washington State in November.
The fact we are in a neutral to La Nina year means that there is a higher probability of more rain than last year (an El Nino year)...something shown for the western Washington lowlands below.
My advice. Make sure you have a decent umbrella.
Wow! Potentially we'll be on the edge of this, near Mt Baker. 'Have the umbrella out, and my XtraTufs dusted off.
ReplyDeleteThe abundant moisture in the atmosphere is evident from the unusually high dew point temperatures that are occurring across the PNW.
ReplyDeleteCliff, I also notice that La Nina years also seem to have the widest range of precip totals. Are there just a few instances of outliers at the extremes, or is there really s bigger dose of uncertainty to contend with when forecasting precip totals?
ReplyDelete