Wintry end to November ahead?
Aside from a quick shot of polar air during the second weekend of November, Northwest Missouri and Northeast Kansas has continued to enjoy mild fall conditions through the last full month of the season so far. The last episode of wintry temperatures brought highs in the 30s and lows in the teens November 9th and 10th. Warmer air promptly took control following the fleeting cold snap as temperatures surged into the 60s and even 70s in the proceeding days.
Looking ahead to Thanksgiving and beyond, a number of meteorological signals are pointing to a stark shift in local and regional weather patterns- favoring periods of below average temperatures. Different from the most recent cold snap, near to subfreezing conditions could last more than just a day or two during the final stretch of November and early days of December.
Climatologically speaking, colder air is a common sense expectation as fall dwindles and winter approaches.Beyond this fact of life, a more obscure phenomenon could be setting the stage for an abrupt turn for the wintry side in the coming weeks- sudden stratospheric warming a.k.a. SSW.
Sudden stratospheric warming takes place in polar and arctic regions of the globe from time to time, characterized by a rapid increase in temperature within a large section of the stratosphere. SSW events happen almost spontaneously, but can have lasting effects on large scale hemispheric weather patterns. Most notably, SSW events disrupt and weaken the polar vortex, allowing polar and even arctic air to swing further south than usual.
Recent forecast models suggest sudden stratospheric warming is likely to take place in late November and early December, at least to some extent. In theory, this could increase the risk of cold air outbreaks and impactful winter storms for much of December across a large swath of the United States.
Whether or not an episode of sudden stratospheric warming takes place, a large ridge of warmth is expected to develop over the Pacific Northwest late next week, sending a shot or two of wintry temperatures across the Midwest and Great Lakes near or just after Thanksgiving. With an abundance of cold air likely to be in place for at least a few days, the first accumulating snowfall of the season is a real possibility. That said, it’s simply too early to discuss the probability of this happening locally over the next two weeks, at least with any real level of confidence.
