Cool Weather Not As Chilly Due To Climate Change. Also Rain Keeps Avoiding Us In Vermont

Broken clouds grace the sky over St. Albans, Vermont
this morning. Unfortunately those clouds will not
yield much rain this week.

Well, we're not exactly dying of heat stroke right now are we?

Autumn in August will continue for a couple more days while at least parts of Vermont will continue to get cheated out of the rain.  

First we'll get into the cool weather, then rain chances. 

As noted yesterday, Monday's low in Burlington was 49, the first time since June 3 it was under 50 degrees. It also was the first August night since 2020 and only the second since 2013 with August readings in the 40s. 

That we're remarking about what was historically an unremarkable overnight low in mid-August is yet another example of how climate change has altered our perspective. 

In the past, most Julys and almost all Augusts would routinely have at least one or two mornings in Burlington that got down into the 40s. 

That has changed. We haven't had a July with a low under 50 since 2015,  

This is the first August since 2020 that got into the 40s,  Of the ten Augusts between 2015 and 2024, eight of them stayed at 50 degrees or above.  In the 110 years before 2015, only five Augusts failed to get under 50 degrees in Burlington.

That's a huge shift. Nights have been warming faster than days under this climate change regime, so that in part explains the warmer nights. I imagine development of homes, businesses and roads around the Burlington International Airport, where measurements are taken, has had some influence on overnight lows. But climate change is almost certainly skewing the data, too.

Given the new weather pattern, we might actually have another night or two in the 40s in Burlington this month. But not right away. 

Clouds last night, and more clouds predicted  tonight are keeping overnights a little balmier than Monday's dawn was. The clouds will keep daytimes cool. Under a somewhat thin overcast with some breaks in the clouds, we should make it into the 70s today. 

Tomorrow should only make it into the 60s under thicker clouds, with maybe some readings near 70 north where the clouds might thin a bit,

Then we'll have a brief warming trend that will make it feel like summer again starting Thursday and continuing into the weekend. Highs on Saturday could reach the mid-80s. 

Early indications are that it will be back to "pre-fall" or "fair weather" after that, with cool weather seemingly in the cards next week, Unless Ma Nature pulls some sort of surprise. 

RAINFALL

We have a more complete picture of rainfall on Sunday, and it really was pathetic. A few places in north central Vermont, around Lamoille County managed about a quarter inch.  Other areas north of Route 2 managed to receive 0.1 to 0.2 inches, which falls well short of a soaker. 

Southern Vermont only got a few hundreds of an inch.

We definitely need the rain,  as is obvious to anyone who has seen everybody's lawn go brown. The Lake Champlain level was at 93.85 feet as of Sunday. That's the lowest level for mid-August in 34 years. The lake usually hits its lowest point later in the autumn. 

The computer models  have been flip flopping a bit on prospects for expected rainfall tomorrow, Earlier forecasts had most of the rain north, but now, southern Vermont seems to be the target for a little relief,

As of this  morning, forecasts call for perhaps a third to as much as a half inch of rain tomorrow, if we're lucky south of Route 4.  Northern areas miss out with a trace to maybe just a tenth of an inch of rain tomorrow.  I expect a few more forecast adjustments between now and tomorrow, so stay tuned. 

After that, it gets dry and warm again through Saturday. A cold front toward Sunday is our next chance of rain.

This far in advance, it's hard to know how much rain we'll get. Some computer models slow the front down near us, which would prolong the rain.  That would be great, but I'll believe it when I see it.  

One Benefit Of Warm Vermont Winter: Ice Jam Flooding Risk So Far Very Low

An ice jam on the Mississquoi River after a thaw in 
January, 2018 diverts water into this Swanton,
Vermont industrial building. 

 If you get a big warm spell accompanied by heavy rain in the late winter or early spring across Vermont, you really run the risk of flooding from ice jams. 

By early February, there should be quite a bit of ice on Vermont rivers, and some of that ice should be pretty thick. 

Not this year. There's hardly any ice on the rivers. 

When a big thaw breaks up the usual river ice, it'll flow downstream until it gets caught on bridge abutments, curves in the river or some other obstruction. 

And, if those chunks of ice are thick, they are not likely to cave under the pressure of more ice and water  coming from  upstream. The collection of ice chunks forms a dam, and flooding results behind this ice dam. 

Just ask anyone who was in downtown Montpelier in March, 1992 what that was like. 

Ice jams like this have historically been a threat almost every winter and spring.

Vermont rivers have remarkably little ice in them at the moment. And the ice that's there is pretty thin, brittle and weak. 

Thick ice on Vermont rivers, ponds and lakes forms when we get a series of cold nights. The near- overcast that has turned us all into tragic victims of Seasonal Affective Disorder has also made our nights incredibly warm. 

January was overall warm, mostly among the top 20 warmest. However, daytime highs in January were generally only sort of milder than average.  Nights were bonkers warm during January, however, among the warmest on record. 

One telling factoid: It got down to 16 degrees in Burlington early this morning, which was the chilliest temperature there since way back on January 22. But this morning's low was still four degrees warmer than normal, but it was still 

As we get into February, temperatures are forecast to be near to above normal maybe all the way to the middle of the month. It looks like we'll have some semi- chilly nights early this week with overnight lows near normal. But another thaw looks like it's coming at the end of the week. 

Clear enough over New England so you can
see snow cover or lack thereof. Lake 
Champlain looks almost entirely free of ice.
Click on pic and zoom in on this view
from this morning. I think the grey, curled
area in middle of lake is a fog bank.

Sure, it could turn really cold in late February and March, and that would certainly increase ice amounts and thickness. But 2024 almost certainly won't be the year of the ice jams. 

LAKE CHAMPLAIN

Meanwhile, much of Lake Champlain remains ice-free.  We haven't been able to get a decent satellite photo of the lake in weeks due to the persistent cloud cover.  So it's been hard to judge how much or how little ice is out there.  

It was better this morning, with mainly clear skies. It looked to me like there was a fog bank in the middle of the lake obscuring some of the view. 

But otherwise, it appears on satellite there is very little ice on the lake, much less than there should be this time of year. 

 Unless it turns intensely cold in late February and we continue to have subzero weather through much of March, Lake Champlain won't entirely freeze. 

 The chances of it being constantly below zero in the first half of March are nil. Which means the lake won't freeze solid again.  

Lake Champlain has only frozen over completely once in the past nine years, though in 2022 it came very close to freezing over, with just one small hole of open water out there in late winter that year.

 

So Far Warm Nights Reign Supreme This Year

Home sweet home. Suns sets over my St. Albans, 
Vermont home during yet another very 
balmy September evening.

 We're back in a trend that seems to be the theme of this year in Vermont so far: Warm nights, relatively speaking.  

By now, we usually start talking about frost in the cold spots around Vermont, but there's no hint of that in the forecast.

In Vermont's banana belt around Burlington, the "coldest" night so far this month was 56 degrees at a time of year that it often gets well down into the 40s.  (Tonight will get down to around 50, so closer).

The last time it was under 50 degrees in Burlington was June 23.

Meanwhile, afternoon highs so far this month have mostly been a little on the cool side, so that overall temperatures so far this month are near normal. That's the newly introduced "new normal," which is warmer than it used to be due to climate change. 

This month is echoing July, which was a tad cooler than average in Vermont under the "new normal."  But nights were a little warmer than average that month. Cloudiness kept afternoon highs depressed during most of July, leading to the relatively "cool" month.

 The trend over recent years with climate change is that nights are warming faster than days. So in general, it's harder to get cold nights. 

Harder, but not impossible. The weather pattern could always flip.   It is of course still possible we could get early frosts this month.  Looking further ahead, there's always a chance that we could have a spell of record low temperatures  But the chances of warm nights, and also record highs during the days are greater than the chances of record lows these days. 

Eight or nine months in one location doesn't prove or disprove much of anything with climate change, but the stats this year from Burlington are kind of telling. We've had seven record highs so far this year but no record lows. 

Record highs far outpacing record lows in the United States
in recent years. Click on the image to make it bigger and
easier to read.

Nationally, record highs are far outpacing record lows at reporting stations.  So far more than 20,000 record highs have been set this year, twice the number of record lows. This despite an incredible February cold snap that brought contributed about 4,000 record lows to the tally. 

Last year had a similar ratio of record highs to record lows.

I didn't keep track of record warm low temperatures this year but there were a few remarkable overnights and mornings. At dawn on Christmas Day last year it was in the low 60s, at a time of year and day when it should have been in the low teens. 

There were a couple mornings in March that were in the 50s, and a few overnights in May that stayed in the upper 60s. And as mentioned previously, we endured 11 nights in August that failed to get under 70 degrees.

These warm nights do have implications in our daily lives. Some of them are benefits.  Warm winter nights help with our fuel bills.  Warmer nights generally extend the growing season, though that can be unreliable. One cold night can screw things up royally, even if most evenings are balmy.

Warmer nights can shorten the ice fishing season and make it less safe.  And it can cut the number of hours Vermont ski areas can make snow to replenish slopes after thaws.

We can't say precisely in the coming weeks or months to what extent this warm night trend will continue. But over the next week at least, there's a good possibility that Burlington will continue to stay continuously above 50 degrees. There might even be a night or two in there that feels vaguely muggy, though the worst of summer's heat is certainly gone.

If this keeps up though, you can continue comfortably having dinner out on the deck well into the autumn.