More Vermont 90s, And Interesting Hot Green Mountain State Trends

Burlington managed to eek out another day above 90 degrees on Monday, making it the 15th day this year already in which it has gotten to the 90 degree mark.

A so-called cold front had passed through earlier in the day, but the slightly cooler air lagged far back in Ontario, so it wasn't really until evening that we began to feel some refreshing breezes from the northwest.

Ben Frechette, a meteorologist at WPTZ-TV, loves looking at data, as I do, shared some more stats yesterday.

I've been saying all along that the average number of days that get to 90 degrees in Burlington each year is five.

That's true if you look at the data starting in the 1880s and going through until now.  However, many climatologists look at the average going back the past 30 years or so.  If you do that, the average number of 90 days in Burlington is eight.

Frechette shared the chart you see in this post.  (Click on it to make it bigger and easier to see).

The chart shows the yearly number of 90 degree days in Burlington dating back to 1883. The darker line you see in the chart is the 30 year rolling average for the entire data set.

As you can, there is a definite trend toward increasing numbers. Such a long term trend suggests to me that climate change is playing a role, but it's probably not the only thing going on.

There are probably some cycles thrown in amid the general climate change warming. You can clearly see a spike in the number of 90 degree days in the 1940s.

Part of that might be because there was less forest in Vermont back then than there is now.  If you have more forests, you tend to have cooler temperatures in the summer because of all the transpiration and water evaporation from the trees.

But there was about the same or even even less forest cover in the decades before the 1940s, and no corresponding higher number of 90 degree days.  For whatever reason, though, the 1940s were generally warmer and drier than previous decades.

Vermont had as little as 20 percent forest cover in the late 1800s due to farmers clearing the land. By the 1980s, forest cover had reached about 75 percent.  It has stayed relatively steady since.

Moreover, rainfall has increased in Vermont during the past few decades, at a rate of about 1.5 inches per decade since 1960 or so.

Scientists think climate change is largely behind the increased rainfall. Remember, all that water from the trees and those rain storms might make it feel more humid in the summer, but the moisture also works to keep the temperatures from spiking.

That's because in wet times, more of the sun's energy goes toward evaporating water than heating the air. Plus, excess moisture can at times create extra clouds, blocking the sun, though that's not always the case.

You'd think the increasing forests and the heavier rainfall would work against an increasing trend of summertime 90 degree weather. But you see the rising trend in Frechette's chart.

One big caveat:  The immediate Burlington area has seen more suburbanization and sprawl over the past four decades than most other parts of Vermont.  The National Weather Service in South Burlington makes sure to calibrate things to ensure accurate temperature readings.

Still, I don't see as much of a warming trend in areas of Vermont that haven't changed as much as the Champlain Valley has. This part of the Champlain Valley has probably lost of bit of forest cover since 1970 or so.

I admit I have not deeply analyzed data from places like Montpelier or St Johnsbury, but I suspect the rising temperature trend lines in those communities might be a bit more tempered.

Maybe Frechette can look at that, although the dude is already incredibly busy with his weather duties at WPTZ.

Will This Be The Hot Summer Most Of Us Dreaded?

Jackson the Weather Dog on Sunday gave up recording
consecutive days of 90 degree heat in St. Albans, Vermont
and found a cool spot on the concrete floor of his
basement to escape the outdoor scorcher. 

I've fled the heat of the main floor of my house and am hiding in the basement as I write today's post. With me are Jackson the Weather Dog and Tonks, our doggie weather assistant.

When the weather makes people hide in basements, it's usually because a tornado is coming.

There is most certainly no tornadoes near me today in Vermont, but the heat sure is baking outside. Only one room of the house is air conditioned, but the basement stays nice and cool. So that's where I'm hiding.

All levity aside, this is getting nasty.

As I write this shortly after 1 p.m., nearby Burlington has reached 90 degrees for the fourth day in a row. It will be the seventh day in this young summer season with at least a 90 degree reading.  Normal for an entire year is five such days.

Forecasts indicate we could be in for two more 90+ days tomorrow and Tuesday before somewhat cooler air arrives later in the week.  

That would give us six consecutive 90 degree days, a record long streak of such weather for June, says the National Weather Service in South Burlington.  It would also tie for the second longest streak of consecutive 90 degree days in Burlington for any month.

Long range forecasts, admittedly not always accurate, suggest the much warmer than average weather could continue through the month of July.

This is all making me slightly worried that we here in Vermont will have our turn to get stuck under a relentless, dangerous heat wave that could last all summer. This is completely speculation on my partm and not based on any real science.

However, there does seem to be an increasing trend in parts of the Northern Hemisphere to have disastrous summer long unprecedented hot spells

Could this be our turn?  Only time will tell.

These heat waves over the past decade have been much more brutal, and much longer lasting than past heat waves. This is almost certainly made worse by climate change, which can contribute to hotter temperatures, and at least according to some scientists, favor "stuck" weather patterns that dont change for weeks or even months.

Some examples:

In 2003, a heat wave settled over western Europe for most of the summer. Temperatures stayed near or above record levels for weeks in August.  The heat killed 30,000 people, 14,000 of those in France.

A 2010 heat wave sent temperatures soaring to 100 degrees in Moscow, with the heat lasting weeks, killing an estimated 11,000 people.

As with any extended period of heat, these massive hot spells created massive droughts.

This year, an intense spell of heat is hitting Siberia. Actually, parts of that region near the Arctic Circle have been off the charts above normal with temperatures all year so far.

On Saturday the city of Verkhoyansk, in northeastern Siberia reached 100 degrees. If that reading verifies, it would be the first time on record a temperature has reached 100 degrees north of the Arctic Circle.

The normal high temperature in Verkhoyansk this time of year is in the upper 60s, and it can get to 90 degrees there occasionally.

I got a bit of a scare of sorts in 2018 when a strong heat wave enveloped Vermont, and especially Quebec in the first part of July.  The heat was persisted for nearly a week with an all time high daily minimum temperature of 80 set on July 2 that year.

Luckily, the heat eased after that first week of July, 2018, though temperatures remained above normal through the rest of the summer.

Long heat waves have happened before in Vermont, but not that  often. The worst was probably August, 1994, when 13 of the first 17 days of the month reached 90 degrees in Burlington. One of those days set the all time record high in Burlington, which still stands -- 101 degrees.

So, back to my question: Are we at the start of a summer long siege of heat and drought? The short answer is nobody knows. We'll just have to wait it out.

The maximum number of 90 degree days in any year in Burlington is 26, set in 1949, so a fairly long time ago.

The trend in recent years is a little dismaying, though, if you don't like hot weather. The last time we had a summer with a below average number of 90 degree days was in 2014, when there were only three such days.

Since then, it has ranged from seven so far this year, eight in 2017 and a yikes-factor 17 afternoons in the 90s in 2018. Have the "normal" summers of five 90s passed us by?

Probably not, but they will also likely become increasingly rare in the future, too.

Hot Autumn Is Messing With Our Fall Foliage

Still a lot of green amid record high temperatures
in these hills near Richmond,  Vermont on Sunday.
Fall colors should be peaking now, but they are
very late due to a hot autumn.

It's fitting that because we've had such a bizarre autumn in the weather department here in Vermont, our famed foliage season is off kilter, too.

In and near the Champlain Valley, there's still a lot of green on the hills at a time when the foliage should be at peak.

No wonder. Those crisp fall days we should have seen in late September were overtaken by a very humid, unprecedented stretch of 90 degree weather.

After a brief cool down to normal temperatures a week ago, it warmed up again over the past five days, culminating in a record high of 80 degrees in Burlington, Vermont Sunday afternoon.

The dew point, a measure of how humid it is, reached 69 degrees late Sunday morning in Burlington. Such readings usually only come during the most oppressive midsummer weather. I've never seen anything like that in October.

All this has left the forests confused. Aside from the late season green, some trees that normally turn brilliant seem blah, and some trees that usually make me go "meh" in the autumn are gorgeous.

I'm going to reserve judgement on how brilliant the colors will end up, but there are a couple of potentially bad signs.

I haven't driven around personally to see, but there are reports that in some places, especially toward northern New Hampshire that have reached peak, the colors were a bit subdued this year.  NECN says the weather extremes this year have put stress on trees, which seems to be leading to fewer of the red and orange blasts of color we are used to this time of year.

However, I have seen photos of the colors in Vermont's Northeast Kingdom and things look as spectacular as ever up there.

Of course, the Northeast Kingdom should be well past peak by now, but this year they're late like everybody else.

I was in the western foothills of the Green Mountains near Richmond, Vermont yesterday and there were certainly wonderful splashes of color within the green. I'm not sure if the rest of the colors will pop later, or if things will be muted. We'll have to wait and see.

Encouragingly, it is going to be seasonably cool during the middle of this week (Highs in the 55-65 range, lows in the 30s to near 40) So I imagine that will make the colors blast out. A spate of coolish weather between the heat waves last week did seem to prompt some color to quickly appear.

We had very warm autumns in 2015 and 2016, too, so the foliage season was a little late those years, but it was spectacular.  So maybe this year will be the same, who knows?

Even if this year's autumn foliage proves to be not quite as spectacular as some years, it's still gorgeous. So get out and enjoy it. Better late than never, right?