Winter 2014/2015: More Like Spring
Hasn't Felt Like Winter? Thank The Jet Stream
Meteorological winter starts at the beginning of December and lasts through the end of February and, while we still have a couple weeks left, this winter hasn’t felt quiet like it should. It’s because we’ve been running above average and dodging snow as well… all thanks to the jet stream.
The jet stream, located about 30,000 ft above the surface, helps guide systems that impact our day to day weather. Typically during the winter months, the jet stream moves farther south, allowing for cooler air to move south as well. While the eastern portion of the United States has seen this, the central and western portion of the United States has been underneath warmer air quiet a lot over the last two months. When warmer air is underneath the jet, the jet responses by ridging or rising more north.
The warmer air underneath the ridge has allowed some places like Rapid City, Pierre and Valentine to climb to temperatures like 60s and 70s. Some of these places set new records in January as well as in early February. In addition to some places setting new records, temperatures for both day time highs and overnight lows were several degrees above normal.
Average Temperature Anomaly for January, 2015
Not only did the ridge bring us the warmer air, but it also kept most of the snow bringing systems to our east. The jet stream helps guide systems on their path across the United States; starting in the Pacific, the low pressure system gather moisture and ride the jet stream north into Canada. That’s where the lows gather the cold air and continue their ride into the United States. Because we’ve been underneath the ridge, these system ride over us, leaving us with cooler air, maybe a dusting of snow while farther east gets more snow.
Snow Depth at Midnight, December 13th, 2014
With the last couple weeks of winter left, cooler air looks to return back to the Plains, but we’ll miss out the snow. A cold front, on the back side of a low to our north, will travel south bringing cold air starting Tuesday. With gusty northwest winds, wind chills will range from 15 – 30 below, especially Tuesday night into Wednesday morning. Make sure you dress warmly and cover as much skin as you can to avoid frostbite.
It’s felt like spring for some of us this winter, but it looks like Old Man Winter isn’t giving up without a fight. Make sure you’re staying warm out there, as we come to the end of the winter season.