Beware the Atmospheric River!

Atmospheric River Animation :: Courtesy ESRL

Mother Nature will unleash a torrent of water at the Pacific Northwest this weekend. Portland could get up to 4″ of rain by Monday morning, a huge amount for September, typically one of the city’s driest months of the year. In fact, dozens of September rainfall records could fall due to this unusually juicy storm.

As for the “atmospheric river” (literally a narrow band of fast moving, super soggy air; in the United States, ARs take aim at the West Coast) that will make for an über-drippy Northwest weekend, it’s not really that visible on today’s satellite images. Or at least it’s not as apparent as in the images from this excellent Weather Channel post from Dr. Greg Forbes, explaining an AR event from 2010.

NOAA’s Earth System Research Laboratory AR page is worth a visit.

The river of moisture in the air (if that doesn’t sound too weird) has moisture from Typhoon Pabuk (named after a Laotian fish) as well as the usual Pacific Ocean moisture. It’s going to get very windy, too.