Heat Wave Is Here in Vermont As Storms Complicate Temperature Forecast

Today's heat wave cure photo. Heavy snow falling in
St. Albans, Vermont, February 26, 2023.

UPDATE 1:15 PM TUESDAY

As expected, those thunderstorms that were in northwestern New York heading into the Adirondacks quickly fizzled by the time they reached Vermont.

But their ghosts remain. Little temperature differences and atmospheric boundaries will probably set off more storms this afternoon and evening.

The storms will be widely scattered, but a few will pack a real punch. NOAA's Storm Prediction Center has now upgraded pretty much all of Vermont to a level 1 marginal risk of severe storms.

That's the lowest level of a five point risk scale for thunderstorms. It means we are under threat for isolated severe storms, nothing widespread.

Those unlucky enough to get a severe storm are prone to microbursts. That means small areas of damaging winds and torrential rains.  So keep an eye to the skies.

The heat is playing out as expected. It had gotten up to 90 degrees in Burlington and a few other towns in Vermont by 1 p.m. Temperatures will continue to climb toward the mid-90s this afternoon, except in areas that get hit by isolated storms. 

Wherever you are, the heat is dangerous. Keep yourself, your friends and your pets cool and well-hydrated today through Thursday, please.

PREVIOUS DISCUSSION

You could really feel the change in the air Monday. 

'Dawn was gusty and cool-ish here in St. Albans, Vermont but by the time afternoon hit, the air was heavy and humid. 

By the time I got out of work late Monday afternoon, the the air here in St. Albans had the distinctive aroma of the onset of an oppressive heat wave. It smelled a bit like burned water, if that makes any sense. 

If you thought last night was warm and muggy, you're right. Burlington might set a record for the highest low temperature for the date. That figure is 73 degrees, and so far the lowest it's gotten is 75.

The heat advisory is still up, and it's still going to get into the 90s, the heat index will still be dangerous through Thursday. But the forecast for exactly how hot it will get has gotten complicated. 

This might turn out to be a stormier heat wave than first thought. 

Most people won't see thunderstorms today and tomorrow. But a few of us will. Predicting how many storms might form and where, and when, and how they will affect temperatures is turning out to be complicated. 

Computer models don't always handle subtle ripples in the atmosphere near the northern edge of a heat dome, where we are. This morning, those models have done poorly.

TODAY

A cluster of thunderstorms came out of Ontario last night and were in northwestern New York, near Watertown as of around 6:30 a.m. These continued on its the western and central Adirondacks by 8 a.m. 

These storms were kind of unexpected, so how they'll affect today's weather isn't being handled well by the computer models. It'll be a matter of monitoring stuff all day to see how things turn out. 

It's unclear how well these storms will hold together as they move east. Will they make it into maybe central Vermont? Or will the outflow from these storms trigger new ones? Even if we don't really get thunderstorms out of this mess today, will the so-called debris clouds from the storms block the sun at times, holding temperatures back?

A cluster of thunderstorms over northwest New York
seen on this satellite photo at around 7:30 a.m today 
might help hold temperatures down a little bit in
parts of Vermont today, but it will still be 
dangerously hot and humid. 

All that is definitely possible.  It looks like this morning's cluster of storms will head into central Vermont later this morning while weakening. So a rough, broad line from Middlebury to Wells River might not be quite as hot today as points north and south. We shall see. 

The wildcard is whether this dying complex of storms will be the seed of new storms once the day's heat really gets instability going. 

The bottom line is it's still going to be really hot and humid today. It actually doesn't matter whether the actual temperature barely hits 90 or gets to 95 or 96.

 Either way, it's so humid that the heat index will be in the 95 to 105 degree range, making strenuous outdoor activity this afternoon dangerous.  

Especially those of us who might be elderly or have health problems should find air conditioning if at all possible.

As far as those thunderstorms go, if any of us gets hit by one, a couple of them could be strong with gusty winds and torrential downpours. The chances of any particular place getting one is low, but the best chances, such as they are, would be from Lake Champlain west.  Keep a careful eye out if you're boating today and be ready to get to harbor quick. Those storms can develop fast.

WEDNESDAY

We have the same questions as today as to whether "debris clouds" from thunderstorms will limit temperatures a bit. Debris clouds are just the leftovers from storms that petered out.  However, there will still be subtle ripples in the atmosphere Wednesday. 

The air is so hot and humid it only needs a little spark to generate thunderstorms, so that's what we're facing again tomorrow. Once again it's unknown if or where thunderstorms might form tomorrow, but they'll probably be few and far between. 

Those storms or their debris clouds might once again raise questions as to how hot it will get.  It'll probably be in the mid-90s in many valleys, but in some places temperatures could be held back to near 90. But once again, the humidity would more than make up for any slight dip in the temperature. This air mass is much more humid that we usually get up here in Vermont.

No matter what, the dangerous heat and humidity rolls on Wednesday. Be safe! 

THURSDAY

There's a better chance of thunderstorms, especially north as a cold front starts to approach from Canada.  The clouds from this might even hold temperatures down into the upper 80s right near the Canadian border.

Thunderstorms could happen anywhere Thursday afternoon and evening, but are most likely along and north of Route 2.  We'll have to keep an eye on these. Some might end up being severe again. 

Thursday will still be the third day of hot and humid weather, so our defenses will be down if we've been enduring the heat for a few days.  You'll need to stay hydrated, find cool air conditioned places if at all possible and don't literally kill yourself with evercise or outdoor physical work. 

BEYOND

That cold front comes through Friday. It's beginning to look like it will come through early enough Friday to avoid touching off another risk of severe storms. Northern Vermont looks more safe from rough weather than the south. 

Although this cold front will bring in cooler, somewhat less humid air, I'm not at all impressed by the looks of this front. It will still be quite warm and humid even after it goes through.  It'll also get hung up nearby, perhaps in southern New England or maybe even close to the southern Vermont border.

That'll keep at least a little risk of showers and storms going. The cold front will probably come back at us as a warm front Sunday, with a new cold front close on its heels. That gives us the risk of more storms Sunday. It's a little too soon to tell for sure, but we'll need to keep our eyes out for possible new severe storms. 

 While we might have brief spells of cooler, drier weather,  the overall pattern favors more warm sticky stuff most of the time though the end of the month, and probably into July.

Since the heat dome will still be around, just to our south, it wouldn't take much for dangerously hot air to surge into Vermont at times later in the month and beyond.