Christmas Seasons Past Shiver Vermont Timbers. Recent Years, Not So Much

 Sure, we have some pretty nippy weather coming up this weekend, and there's snow in the forecast here and there.  

A pre-Christmas snow globe look to Burlington's
Intervale in December, 2017.  Holiday season
cold and snow use to be pretty extreme in Vermont
decades ago, but in recent years, not so much. 

But comparing this season with Vermont's holiday season history of intense cold, blizzards shows just how wimpy pre-Christmas weather has gotten in recent years.   

As I mentioned this past Sunday, this has been a pretty easy early winter.  In many years in the week or so leading up to Christmas, the weather turned Vermonters' Ho Ho Ho quickly into Bah Humbug.

The most recent example came just last year, when destructive flooding smashed parts of the state on December 18-19, inundating neighborhoods, already damaged by floods a few months later, and ones that would be damage again the following July. 

More often than not, though, the pre-Christmas rush has been marked by intense cold and way too much snow and wind.

FRIGID CHRISTMAS HISTORY

According to David Ludlum's Vermont Weather Book, the worst example of this takes us way back to 1835.   The "high" temperature on December 16, 1835 was in the mid-teens below zero. Northwest gales that day probably plunged wind chills into the 40s or even 50s below zero.

Some other notable Christmas season cold snaps that will make this weekend's expected overnight lows near 0 seem like a walk on the beach at Key West:

1942: Early season record cold greeted Christmas shoppers on December 20. Lows included 23 below in Burlington, minus 29 in St. Johnsbury and 32 below in Newport. 

1955: Records still stand for the coldest for so early in the season in Burlington, where it was 22 below in December 21, minus 20 on December 22, and then "warmed" up to a balmy -18 on the 23rd. At least Christmas Day itself that year was warm, as temperatures rocketed up to 41 degrees.

1958: West Burke was below zero every day from December 8 to 27, with the temperature dropping to 29 below on the 11th and minus 30 on the 12th.  Of the 25 days leading up to Christmas that year in Burlington, lows on 21 days were in the single numbers above or below zero. 

1970: This was probably the harshest pre-Christmas on record if you combine low temperatures and extreme snowfall. Repeated snowstorms with intense cold started on December 4 that year.  By Christmas Day, there was 32 inches of snow on the ground in Burlington. 

Since we're talking about pre-Christmas weather, December 22, 1970 stands out. Heavy snow, strong winds and subzero cold all combined to put the kibosh on pretty much every holiday party planned that day. Temperatures stayed below zero all day in most of Vermont amid heavy snowfall and gale force winds. Blizzards, especially those that cold, are no fun.

Montpelier had 31 inches of new snow between Dec. 17-24, 1970 bringing the depth of snow on the ground to 43 inches on Christmas Day. Temperatures were as low as 21 below in Montpelier a low of minus 21 and a high of 2 above with 5 inches of snow that 

1989: This was l the coldest December on record in Burlington. Fourteen days between the first of the month and Christmas got below zero in Burlington. In Montpelier, not one day that December got above freezing until the 31st, and 24 days got below zero.

WARM RECENT DECEMBERS

Recent years have mostly been just the opposite of this frigid pre-Christmas and Christmas history in Vermont. 

On Christmas Eve, 2015, for instance, the temperature reached 68 degrees in Burlington, which is the warmest December on record. It was a balmy 70 in Rutland that day.  

Fresh green daffodil shoots pop up Christmas morning,
2020 amid record warmth in the 60s.

On Christmas morning 2020, it was 65 degrees in Burlington for a new record high.

  At 8 a.m. EST that Christmas morning, the Lower 48's warmest U.S. weather station was, of all places, Highgate, Vermont, on the Canadian border with a temperature of 65 degrees.   At that hour, it was 54 in Miami and 49 in Phoenix. 

December 16 and 17, 2021 both reached 60 degrees in Burlington.  

This coming weekend, we in Vermont are expecting the sharpest pre-Christmas cold snap since at least 2019.  Which actually isn't saying much, given the warm Decembers of the past decade.

High temperatures this weekend and the start of next week will probably only make it into the teens to around 20, with lows of 0 to 10 below, even chillier than that in the colder mountain valleys.  

That kind of weather would have almost felt like a warm spell during many of the frigid Decembers back in the 1950s, 60s and 70s.

And true to modern form, after the cold snap this weekend, it seems likely Vermont temperatures will likely soar to well above normal levels as we head into Christmas next week. 

"Bowling Balls" Of Chilly Air Will Keep Interrupting Vermont Spring

Skies looked rather volatile last evening in St. Albans,
Vermont as a burst of cold air from Canada stirred
up some showers, clouds and downdrafts.

 It got awfully gusty at times and temperatures took abrupt tumbles Saturday afternoon as the first in a series of what I call "bowling" balls of chilly air invade our Vermont spring. 

While the northern hemisphere is warming up as the sun angle rises, it takes time to scour the pools of biting, winter cold air out of the Arctic.

These pools of frigid air tend to wander around up there as pieces of them get dislodged, inching the north toward spring. 

That cold pool for now is near Hudson Bay, Canada, which means it's in fairly close proximity to us her in Vermont.

Lucky us! For now, the pieces of nippy air that are breaking off from that frigid swirl of air in Canada are landing on, or at last near our doorstep. I refer to those pieces breaking off as bowling balls because they're compact, roll down from the north quickly, then move back off to our north and east just as fast. 

They're sort of drive-by cold snaps, if you will. 

A few days ago, it looked like these quick cold blasts would largely miss us here in the Green Mountain State. That forecast has obviously changed for the worse, at least if you like spring. 

We do see these pretty frequently in the spring here in Vermont. They're disheartening, but quick hitting, and spring resumes soon enough. Here's how our bowling match will play out this week. 

BOWLING BALL #1

The first one, the weakest of three that we'll deal with this week, came in Saturday afternoon.

The cold front had a fair amount of oomph to it, but the air was really dry.  The spring sunshine helped created updrafts that ran into the very cold air aloft.  This built up towering showers clouds. But that dry air down in the lowest few thousand feet of the atmosphere evaporated some of the precipitation coming down. 

The showers themselves had downdrafts to them. The evaporating rain and snow cooled the air further. The downdrafts and cold, dense air created by the evaporation rushed downward, causing those strong wind gusts at times Saturday afternoon. 

I'm sure a few places gusted to over 40 mph, perhaps 50 mph. I noticed the National Weather Service in South Burlington hoisted a few special weather statements, warning of gusts that high. 

It was cold enough for snow to fall in the upper elevations. Some places had graupel which is sort of a snow/small hail hybrid.  Our first bowling ball also created some dramatic late afternoon and evening skies over the region. Dark clouds, shafts of bright sun, gushes of rain and snow visible here and there, and some wild rainbows.

Today is cooler, with clouds mixed with some sun and breezes behind yesterday's "bowling ball.

The second one comes through this evening and overnight.

BOWLING BALL #2

Once again the air is dry but the cold front with this is strong. That should set off some gusty winds, scattered showers, and eventually, snow showers overnight. Temperatures will take quite a tumble, and we'll see the coldest air since late March by dawn. 

This by no means will be record cold, but it will be shock to the system. It'll be down in the 20s for pretty much all of us and northwest winds will make it feel colder.

If you have magnolias blooming, there's a good chance they'll become brown wreckage after this unfortunately. But the vast majority of garden plants current growing should survive just fine. 

Monday will be sunny, which will deceive you into thinking it's nice out. It will be cold for the season with highs only in the 40s.  The sun, gusty northwest winds and very dry air could create something of a fire danger.  Tis the season for that, as I explained in a post last week. 

Monday night will be cold, too, though it will warm up west as the cold bowling ball departs.  Tuesday will bounce back nicely to near 60 degrees.

BOWLING BALL #3

This has the potential to be the strongest and perhaps the most disruptive of the three, depending on which computer forecasting model you want to believe. 

The cold front and embedded low pressure will come in from the west and north, so rain will break out Tuesday night and Wednesday. So far so good. 

Then, the cold air rushes in, changing rain to snow, yes snow, Wednesday afternoon or evening. Probably even in the valleys. 

If you believe the European computer models, the storm won't linger much, so only a little snow will fall. If you believe the American model, this thing might linger for several hours, which could dump several inches of snow Wednesday evening and night. That's especially true along the western slopes of the Green Mountains. 

I'm not sure which one to believe yet, but of course I'm rooting for the European model on this one.

We do know we have another hard freeze Wednesday night, and probably Thursday night, and a chilly day Thursday.

After that, it starts to warm up, and we can forget the bowling balls for awhile. We'll go back to our regularly scheduled spring.  

As always, stay tuned for updates. The forecast could well change! 

Maybe Those Winter Storms Were NOT Caused By Jet Stream Made Weird By Climate Change

There's new debate over the specific mechanisms causing
intense winter snaps in places like the U.S. and
Europe despite an overall warming climate.

A theory about sharp winter storms and cold waves made paradoxically worse by a warming climate just took a big blow. 

I've mentioned this idea several times before during rough winter weather in the past, but here's a recap:

The theory is that the Arctic is warming faster than the mid-latitudes. That reduces the contrast in temperature between the far North and places down here. 

The reduced temperature contrast slows the jet stream, making it more prone to having bigger twists and turns along its path.  Occasional bigger southward dips in this jet stream regime would create a few intense cold snaps and winter storms, despite an overall warming climate. 

This idea gets floated a lot, like during the big Texas freeze and winter storm back in February. And it really does make sense. 

Except that new research suggests this whole wavy jet stream scenario isn't happening after all. Or at least isn't happening as much as some first though. 

The journal Science published an article recently about this new research.

As Science states:

"Now, the most comprehensive modeling investigation into this link has delivered the heaviest blow yet: Even after the massive sea ice loss expected by midcentury, the polar jet stream will only weaken by tiny amounts - at most only 10% of the natural swings. And in today's world, the influence of ice loss on winter weather is negligible, says James Screen, a climate scientist at the University of Exeter and the co-leader of the investigation."

The thought that a fast warming Arctic would screw around with the jet stream gained notice in 2012 through a paper by scientists Jennifer Francis and Stephen Vavrus that examined this idea.

Francis and Vavrus had detected a weakening of the jet stream between the 1980s and the early 2010s that bolstered their theory of a more lame, meandering jet stream causing occasional extreme winter events in North America and Europe.

That weakening trend has since petered out even as carbon emissions and climate change continued unabated.

Of course, as Science notes, something else might be going on in the overall warmer atmosphere that is causing those occasional, intense, record breaking winter cold snaps that are interrupting our warmer winters now and then. 

Is less sea ice, combined with a trend for more snow over recent decades in Siberia, causing stratospheric disruptions. Those stratospheric disruptions mess with the polar vortex.  The polar vortex - a giant whirl of cold normally in the Arctic - then gets blown to pieces temporarily, helping send frigid air from the North Pole to places like Texas or Great Britain. 

Or, maybe atmospheric rivers - channels of warm, wet air - heading toward the Arctic more frequently, somehow displacing the normal icy air up there and sending it southward to torture the snow birds in normally temperate climates?

All this uncertainty proves the following: The basic science of climate change is settled science. Anyone who still believes the climate is not changing because of carbon emissions is either a crackpot or lying. 

However, the detailed mechanisms of this warming - how it affects specific weather events, specific locations and specific aspects of our complicated atmosphere - still need lots of study.

It's important to do so, because the more understanding we have of the deep details of climate change, the better society will be at anticipating and reacting to the negative effects of what we're doing to the atmosphere. 

 

 

Just Remember: Gorgeous April Weather Could End In Unwanted Karma

Spring surprises. This is what it looked like on April 28, 
2010 in St. Albans, Vermont in what had otherwise been
a warm month. Spring surprises like this happen a lot! 

 Since I'm a glass half empty kind of guy let's throw a bit of cold water on this gorgeous spring week in Vermont.   

Yes, we need the rain, but you can't deny we have entered a period of wonderful early spring weather. It was sunny, with cool but pleasant breezes Sunday through Tuesday. 

For the rest of the week, it'll be in the 60s for most of us, which is at least 10 degrees above normal. The sunshine will continue. 

Yet, April is fickle to say the least, and we can still get some awful throwbacks to winter. I'm not saying it's going to happen, but there's always that risk. 

It's always fun to consult "The Vermont Weather Book" by David Ludlum to find the "it can always be worse" stories. 

Probably the crappiest April in Vermont history was 1874.  Several snowstorms struck the state that month, the biggest of which was on April 26, near the close of the month.  Bellows Falls had two feet of new snow, and low elevation Burlington still managed nine inches.

It snowed again on April 30, 1874. Sleighs were still running on the streets of Woodstock, and nearly three feet of snow remained on the ground in St. Johnsbury.  

In modern times, the greatest April snowfall on record, at least in Burlington, came on the 16th and 17th in 1983. That storm dumped 15.6 inches on the city. 

On April, 27-28 2010, which was actually an unusually warm month, snow hit parts of Vermont, especially the northern Champlain Valley hit while trees were prematurely leafing out. Burlington received 5.3 inches and 10 inches clobbered St. Albans.  Particularly around St. Albans, there weas heavy tree damage as the weight of the snow on partially leafed out trees was too much. 

Typical of the season, though, it was back up to the mid 70s by May 1 and in the mid-80s by May 2.  

You think we're done with subzero cold?  Nope! It's still possible, but frankly not in the cards this year. On April 5, 1954, it was 12 below in Lemington, Vermont and 10 below in West Burke.  It warmed up a couple days later and the rest of April, 1954 was kind of average, so that was good, I suppose.

It was almost as cold in April, 1972.  It got down to 2 above in Burlington, still the record for coldest reading in April there. It was 2 below in Enosburg Falls, and there was still 39 inches of snow left on the ground in high-elevation Peru, Vermont that day. 

What had been an early spring being interrupted by a snowstorm
on April 28, 2010 in St. Albans, Vermont

Unlike in 1954, it never really warmed up all that much later in April, 1972.  Most days for the rest of the month only made it into 40s to around 50 for the rest of the month.  

All but four nights that month got below freezing. I bet the trees were awfully late leafing out that year. 

April can be extreme the other way, too.  There's been at least a couple notable hot spells this time of year, too.

On April 18 and 19, 1976, high temperature records for the month were shattered as it got to 91 degrees in Burlington, which was then by far the earliest 90 degree reading on record. Vernon reached a remarkable 97 degrees.

Consistent with April, however, a little over a week after that heat wave, it snowed a little.

On April 17, 2002, another early season heat wave set a new record for earliest 90 degree reading on record in Burlington. Same thing as in 1976. It snowed a few days later. On top of that, a very hard freeze damaged premature tree leaves and fruit tree blooms.

This April, forecasts call for temperatures to remain above normal for about a week.  Then a possible change in the weather pattern is likely after that.  Will we receive our (inevitable?) late April snows and frosts? Time will tell, but Vermont's track record in this regard makes me think we will.