December 2016 Climate Summary Now Available

Overview - A Switch to Cooler and Wetter Conditions

The warm pattern that had been present throughout much of the fall finally gave way to cooler conditions to begin the winter season. Arctic air masses pushed their way through the High Plains several times during December, contributing to monthly departures of up to 8.0 degrees F (4.4 degrees C) below normal in parts of the Dakotas and Wyoming. The greatest departures occurred mostly during the early and middle part of the month, punctuated by a bitterly cold outbreak of Arctic air on the 17th and 18th that brought the coldest temperatures of 2016 to some parts of the region. Temperatures in several locations dipped below -30.0 degrees F (-34.4 degrees C), which is in stark contrast to last year’s mild winter season. Two locations had a top 5 coolest December on record: Rapid City, SD (3rd coolest) and Chadron, NE (4th coolest).  

The cooler temperatures were accompanied by wetter conditions throughout a large part of the region. Several storm systems brought rain, freezing rain, and snow to the High Plains, and the region experienced a wide range of weather events, including blizzards, ice storms, thunderstorms, and even tornadoes. One of the largest systems moved through on Christmas Day, creating hazardous travel conditions where wintry precipitation occurred and causing damaging thunderstorms on the warmer side of the system. These systems did have some positive impacts. For example, the moisture was beneficial to parts of the Dakotas where drought has been persistent, and improvements were made in these areas on the U.S. Drought Monitor by the end of the month. Also, ample snowfall occurred in the Rockies in Colorado and Wyoming, which helped the mountain snowpack recover after an abysmal start to the snowpack season. However, not all parts of the region received excess precipitation in December. It was much drier in Kansas and eastern Colorado, and some areas of these states experienced below-normal precipitation in December as well. As a result, drought conditions persisted in western Kansas and eastern Colorado, and abnormal dryness was introduced to eastern Kansas during December by the U.S. Drought Monitor.

For more information on temperature, precipitation, and impacts from climate in December in the High Plains region, please see the link to the full PDF of the summary: http://www.hprcc.unl.edu/climatesummaries.php