It’s been cold across the northern tier (North Dakota, Minnesota and Wisconsin, in particular). Places such as Minneapolis, MN were 7.3 degrees below average during December 2013. Minneapolis reported 6 days during the month with average daily temperatures below zero and 6 days with daily average readings at least 20 degrees below climatological expectations. Green Bay, WI was a chilly 6.5 degrees below average for the month. Bismarck, ND reported temperatures 8.8 degrees below average for the month, with at least two days with temperatures 29 degrees or more below average.
Now, it’s actually going to get noticeably colder!
An air mass from north of the Arctic Circle is moving into the northern Plains and the western Great Lakes. The leading edge of this arctic air mass moved across southern Minnesota yesterday morning (Fig. 1). A reinforcing surge, with temperatures in the minus 20 to minus 40 range (and wind chills as low as minus 60) will be in control of Minnesota and Wisconsin weather by early Monday (Fig. 2). Wind chill readings below 50 degrees can cause exposed skin to freeze in a few minutes (Fig. 3). Nearby states will be affected, but to at least slightly lesser degrees. The cold air (with low wind chills) will also infiltrate the Deep South, but be relatively short-lived.
Nonetheless, weather records will likely be shattered by this, “coldest air mass in roughly 20 years.” National Weather Service (NWS) Forecast Offices across the upper Plains and western Great Lakes are showcasing the magnitude of this arctic blast compared to ones from 15 to 20 years ago and further back in history.
For example, at Milwaukee, WI, the record low maximum temperature for Jan. 6 was minus 8 (1912); the forecast high for Milwaukee tomorrow is slated to be minus 10. Madison offers similar testimony with a record of minus 14 and a matching forecast high. Eau Claire, WI may tie its coldest high temperature of minus 16 (1912) and approach a record daily low (minus 32 in 1912) on Jan. 6.
Minneapolis, MN’s high on Jan. 6, is forecast to match the 10th coldest high temperature on record (120 years of data). At St. Cloud, MN, the forecast high of minus 19 on Jan. 6, is expected to eclipse the record minus 15 (1912).
In the face of these brutally temperatures (and associated bitterly cold wind chills), Minnesota’s Governor Mark Dayton ordered that all K-12 public schools be closed Monday (Jan. 6, 2014) to protect Minnesota school children. Other nearby states, counties and/or local jurisdictions will likely follow suit.
These cold temperatures and low wind chills will not deter football fans from attending the NFL playoff game today (Jan. 5, 2014) in Green Bay. The temperature at game time will not be record-shattering; however, it will be among the top 7 coldest starts in NFL/NFC history (dating back to 1954).
By later this week, the arctic blast will relax its grip on most locales (Fig. 4) and allow a January-type thaw to set in for a few days. However, by the middle of the following week (Jan. 15), arctic chill will again be on the menu for the northern Plains and the western Great Lakes (Fig. 5).
© 2014 H. Michael Mogil