Wednesday, February 19, 2014

Second Polar Vortex Intrusion Possible

We may have to deal with another intrusion of the polar vortex in just a handful of days.

Shown above is the GFS ensemble mean forecast of 500mb height anomalies over North America. We see a situation eerily similar to the one that brought about the severe cold in early January 2014. We see a Rossby Wave pushing north into eastern Alaska and Canada, as the strong positive 500mb height anomalies shows. As a result of this strong high pressure, we see a lobe of the polar vortex dropping to the south from Canada. This lobe of the vortex is illustrated well by the deep greens and low contour numbers superimposed on those deep negative height anomalies.

The GFS Ensemble 850mb level (5,000 feet level) temperature forecast for that same timeframe shows how cold conditions may get if this lobe of the polar vortex decides to scrape the United States just to our north again.

The GFS Ensemble Control 850mb temperature anomaly forecast is even stronger, with anomalies as low as -28.4 degrees Celsius in the core of the lobe of the polar vortex.

There's good reason to be concerned about a second intrusion of a lobe of the polar vortex: The Lezak Recurring Cycle supports it.

500mb chart from January 6th
The Lezak Recurring Cycle, or LRC, is a tool developed by meteorologist Gary Lezak that, in essence, can enable forecasters to predict the overall weather pattern months in advance. The gist of the LRC involves a cycling weather pattern that develops in October and November of each year; no pattern is the same from year to year. Around mid November, the LRC begins to repeat, meaning we start to see a similar weather pattern in mid November that we saw in early October. This means that the cycling pattern has begun, and it will continue to cycle on a regular, somewhat-unchanging 40-60 day interval for the next ~10 months before it dissipates over the following summer. This season, the length of the LRC has been pegged at 57 days. If we take the January 6th date and move ahead ~57 days, we arrive in the timeframe of late February, a couple of days within the very cold weather the GFS Ensembles showed above. Considering the LRC has been an efficient tool of use in not only this winter season, but in prior winter seasons, this is likely a real threat of a lobe of the vortex coming south once again.

To sum up:

•The atmosphere looks primed for a strong cold blast in late February that will likely produce anomalously cold weather.

Andrew

13 comments:

Ian said...

When do you suppose we may see it start to worm up? Thanks.

Shawn said...

Here's hoping a strong snowstorm occurs during the cold air especially over Missouri! :)

Elizabeth said...

Thank you Andrew for giving me hope that Winter is not over !!! Really enjoy your posts....appreciate all of the hard work-Thanks!

TheKingj666 said...

Does this support any snow in or ahead of the Vortex, and if so, how much are we looking at here in North Central Indiana? Hopefully I will get to make more money.

Anonymous said...

good! I hope winter spills into April.

Anonymous said...

As usual, the east coast will get all the media coverage, even though it will be the Central Plains that get the greatest departures from normal. Incredibly cold winter in Kansas City...with many afternoons 25-35 degF below normal.

Anonymous said...

Why do all these people want more winter? One of the absolute coldest in history across the Midwest and Great Lakes. More snow=more car accidents, more damage to your house's/car's paint, more travel/air traffic delays, and much higher heating bills. What is good about any of that. Winter has lasted much longer than average...time to move on.

TheKingj666 said...

In my case, the more snow the more money I make. I am the owner of a Lawn Company and I make my bill money by blowing/plowing snow. Without grass and snow, I am stuck doing plumbing/heating. I would much rather blow snow then clean up a crawlspace. If winter would last till spring, I would be happy as a lark.

Frank Reid said...

The GFS and other long-range models are hinting at a Four Corners low blasting through from 1-3 March with some attendant Gulf moisture. This low, combined with those frigid temps are going to wring the moisture out early. The result (and this is a long way off) will be a serious blizzard in the Eastern Nebraska, Iowa and Wisconsin. Your thoughts?

Frank-o said...

Hmmmmmm....Why do people "want" more Winter?.....There are many of us who Love Winter and all it brings. Most of us who truly love Winter....... dislike summer/heat and all it brings....Give me a Winter any day over summer day.....

Elizabeth said...

Right Frank-O!! (and others) there are people like us who prefer Winter over Summer.....the chill in the air ,the silent hush during a snowfall, the beauty of the landscape wearing its winter whites etc. After all , there are negatives about summer too- the deaths from high heat the tornado damage and flooding just to name a few- i realize i am in a minority - and it is o.k. if you want to like Summer...for me though-Winter rocks!

Anonymous said...

Andrew....It appears you are in the grip of the polar vortex! Any ideas on what kind of spring we can expect here in middle Tennessee?

Thanks, Uncle Mike

Andrew said...

Uncle Mike: Luckily, we aren't in the vortex anymore, but it was awfully cold here last month, and even earlier this month! I would bank on a back and forth spring, with warm and cool periods. Probably some good severe weather events too, as tornado alley shifts a bit north and east this spring. Though, I'm sure "chilly" weather down in Tennessee is far nicer than what passes for "chilly" weather here ;)