Early-Season Winter Storm Blasts North Central U.S.

The winter of 2014 - 2015 is off to an early start over the Northern Plains, where a December-like blast of Arctic air is bringing heavy snows and wintery cold. The early season cold air outbreak is due, in part, to the influence of Super Typhoon Nuri, which caused a ripple effect on the jet stream when the remains of the typhoon "bombed" over the weekend into one of the most intense extratropical storms ever observed in the waters west of Alaska. This superstorm forced the jet stream to bulge far to the north over western North America, bringing a strong ridge of high pressure responsible for numerous daily record high temperatures in California, Nevada, Idaho, Montana, Wyoming, and Washington over the weekend. A compensating southwards dip in the jet is now materializing over the North Central U.S., where an unusually powerful trough of low pressure is pushing southeastwards. This trough will give most of the eastern two-thirds of the U.S. high temperatures 10 - 20°F below average by late in the week.


Figure 1. Jack the snowman takes shape after an early season snowfall on Sunday November 9, 2014, in Pellston, Michigan. Image credit: wunderphotographer jpboris.

The wintery fun is in full swing this Monday morning in Central Minnesota, where a Winter Storm Warning is posted, with snow amounts of 6 - 16" expected. According to NOAA's latest storm summary, the storm had a 990 mb surface low pressure in Nebraska at 9 am EST Monday, and brought 3 - 5" of snow across portions of North Dakota, South Dakota, and Minnesota, with heavier snows of up to 14" recorded in Montana. Strong winds pouring south out of Canada brought numerous wind gusts in excess of 50 mph to Montana, Nevada, Idaho, and Wyoming, with the top gust an impressive 68 mph at Driggs, Idaho. The heaviest snows from the storm will likely fall in North Central Wisconsin, with 8 - 16", and in Michigan's Upper Peninsula, where lake effect enhancement by Lake Superior will bring widespread snows over 12", with some areas seeing up to 24".

Jeff Masters