Wednesday, December 14, 2016

Here Comes the Polar Vortex... Again!

The last time the dreaded Polar Vortex invaded the lower 48 states was nearly three years ago, in January 2014, and it was pretty rough, especially for rosarians in parts of the country who aren't used to deep cold, as we are here in the Upper Midwest.  I remember writing back then that we would probably see a vortex invasion again, because it's something that's always circulating up there at the north pole, and it would be just a matter of time before it found its way south again, especially with the weather anomalies we are experiencing on a regular basis these days.  I also cautioned readers in my previous blog "Five Important Steps for Winterizing Your Roses": "Don't forget the Polar Vortex of a couple of years ago (and act accordingly)!"
http://theminnesotarosegardener.blogspot.com/2016/08/five-important-steps-to-winter.html

Well, I hope you did, because here it comes again!  However, for those in zones 6 and 7, If you didn't get all your winter work done, you may have a few more days to protect your roses from the effects of freezing and thawing.  See the animated map below to see when the vortex will strike your area.

The good news is that this particular polar vortex incursion isn't going to last too long.  Obviously, we can't know for sure, but there seems to be a pretty good chance that the vortex will not repeat itself in January, when the the polar air is considerably colder

This is all from my friend Paul Douglas' blog, which I read daily:


What Is The Polar Vortex? NOAA has a very good explainer, separating fact from hype: "...The polar vortex is a large area of low pressure and cold air surrounding both of the Earth’s poles. It ALWAYS exists near the poles, but weakens in summer and strengthens in winter. The term "vortex" refers to the counter-clockwise flow of air that helps keep the colder air near the Poles. Many times during winter in the northern hemisphere, the polar vortex will expand, sending cold air southward with the jet stream (see graphic above). This occurs fairly regularly during wintertime and is often associated with large outbreaks of Arctic air in the United States. The one that occurred January 2014 is similar to many other cold outbreaks that have occurred in the past, including several notable colder outbreaks in 1977, 1982, 1985 and 1989. There are several things the polar vortex is NOT. Polar vortexes are not something new. The term “polar vortex” has only recently been popularized, bringing attention to a weather feature that has always been present..."

Here's the full description:

And here is an excellent,timely article from the New York Times: "Feeling a Chill? Blame the Polar Vortex. And Global Warming".

http://www.nytimes.com/2016/12/15/science/feeling-a-chill-blame-the-polar-vortex-and-global-warming.html?smid=tw-share&_r=0

And here is Paul Douglas' take on the odds of this happening again this winter:

Late-Month Moderation. I want to see a few more model runs, but GFS 500 mb predicted winds looking out 2 weeks suggests a more zonal flow for the USA with temperatures at or above average for late December. The question is not: will we endure more arctic fronts. We will. The question is how pervasive will bitter air be east of the Rockies? Will the polar vortex weaken and break down, allowing subzero air to consistently flood south? I'm still not convinced it's going to be nearly as numbing as it was 3 years ago.

Thank Heaven! But it's better to be safe than sorry.

The map below tracks the polar vortex incursion through the end of December:




2 comments:

  1. That is really good and informative blog. Everyone should have knowledge about polar vortex. Thanks for sharing it with us, will be passing it among my circle.

    ReplyDelete