BLOG: IS WINTER OVER? (DID IT BEGIN?)

I am frequently asked “what happened to the winters we USED to have?”, “where is all the snow”, “are we ever going to get a BIG storm?” etc. These are good questions and important ones. The atmosphere is extremely complicated and SIMPLE answers are often hard to come by.

I have spent a considerable amount of time this winter debunking the myth that winters were much colder and snowier in the 70s and 80s. They simply were not…in fact the 2010s have been the SNOWIEST decade (so far) since at least the 1960s. We also had back-to-back harsh winters, the likes we have not seen since the late 70s, just 2 and 3 years ago. Our memories can be quite short (on any number of subjects!) and weather is no exception.

The maps tell the story: here are the temperatures (compared to average) through February 13 in 2014: conus_ytd_t2avg_anom_2014.png

2015: conus_ytd_t2avg_anom_2015.png

And this year: conus_ytd_t2avg_anom_2017.png

The contrast is pretty remarkable.

One of the hallmarks of this winter season (and last year too) has been the lack of SUSTAINED cold. It gets cold for a couple or few days, but then it just gets mild again.

highsunder25.png

There really has just been one cold “snap” this season, early in January and it lasted 4 days. Notice all the cold snaps in the winters of 2013-2014 and 2014-2015.

WHY??

The reasons for the balmy winter weather are complicated. It’s easy to just be flippant and say “GLOBAL WARMING!!!!!”. I hear that a lot. The climate IS changing, but attributing individual weather events and even warm spells on the scale of months directly to climate change is unwise.

The simplest explanation for our mild winter lies over the Pacific ocean. A very strong jet stream, perhaps being aided by something called the Quasi-biennial oscillation (which has been record strong lately) has been unrelenting in recent months. The result has been a VERY wet winter in California and the West Coast. pacjet.png

Another result? Mild air floods the eastern 2/3 of the country. This Pacific jet acts as a real barrier for arctic air trying to come south in eastern North America. This “top down” view, looking over the North Pole, shows the west-to-east upper-air flow over North America. The cold stays “locked up” near the pole and/or gets shoved into Asia. poledown.png

THE REST OF WINTER

I see very few signs that this overall pattern will change for the rest of the season. Will it snow? Yes. Will it get cold occasionally? Yes. Like….in less than 24 hours! Wind chills by Thursday will be mainly in the single digits and teens: chillsthursam

There can be a couple of inches of snow in our northern viewing area, especially in Mercer County, Wednesday into Thursday. hiresp_snow_cleveland_61.png

But that’s gonna be it for snow for a while. A VERY balmy pattern will take over this weekend into next week. A high near 60 can occur for at least a few days: KYNG_2017021400_eps_min_max_15.png

The long-range modeling shows the same kind of pattern that we have been in all winter. Warm overall with brief periods of cold. The latest European model temperatures for the next month: eps_t2m_768h_conus_129.png

The American CFS model for March (average of last 14 runs): cfs_anom_t2m_noram_201703_56.png

Looks familiar.

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