Another Hot Vermont Day, Chances Of Strong Storms Remain, Maybe

Severe storm risk in the Northeast today. Highest risk
is in the orange areas. Lower risk in the green areas.

UPDATE 10 PM SUNDAY

No severe weather developed across most of Vermont this evening, but surprisingly, we're not out of the woods yet.

A severe thunderstorm watch is now in effect for northern New York and northwestern Vermont until 5 a.m. Monday.

This is highly unusual, as most severe storms develop in the afternoon and evening, then diminish at night. 

Apparently, though, the atmosphere is still primed for the possibility of severe storms.  A destructive tornado has been reported upstream from us, in southern Ontario, Canada, a little north of Lake Ontario.

As of 10 p.m., lightning detection showed quite a bit of activity in southern Ontario, edging toward northwestern New York. 

The earlier computer models were kind of right taking downpours through both northern and southern Vermont this evening. The northern Vermont storms were weaker than many forecasts called for. A few storms in far southern Vermont did carry severe weather warnings. 

The storms overnight, especially in northwestern Vermont will still carry the risk of strong damaging wind gusts, and even a very low chance still of a brief spin up tornado.  Torrential thunderstorms expected statewide overnight and on Monday morning still carry the risk of torrential rains and local flash flooding. 

UPDATE 5:30 PM SUNDAY

Very few thunderstorms, none of them severe have so far erupted around Vermont today.  

That's kind of to be expected, because forecasts had called for most storms to get going in the late afternoon and evening.

Still, it's even a little quieter at this hour than expected, but there's still a window for severe storms in the next few hours. 

Later on tonight, and tomorrow morning, the risk of local flash floods also remains in play. 

The air is very humid and unstable, so it's primed for storms. We just need a trigger to set them off. 

I think an area of clouds that moved across much of Vermont today helped squelch the chances of any big storm development, at least until now. 

The cold front is still way to the north, so that won't be a factor before midnight. Instead, maybe a weak boundary or outflow from a distant Quebec storm might initiate new storms. 

If anything gets going this evening, chances are it will go from a nothingburger to something dangerous pretty quickly.   Some, but certainly not all of the short range computer models are still insisting on what looks to be strong storms in northern Vermont north of Route 2 this evening, and some more mostly south of Route 4.

There were signs as of 5:30 p.m. that something was perhaps, maybe ready to take off and turn into a storm or cluster of storms over northern New York.   But it wasn't definite.

So it's a wait and see game if on whether we see any severe weather this evening. 

Overnight and basically into early Monday morning, more showers and storms are expected to fill in across the region. Some of these will have really torrential downpours. 

For most of us, this will mean a relatively sleepless night, with high humidity, and occasional lightning and thunder and the roar of downpours on the roof. For an unlucky few, we still have the risk of flash flooding in some spots that really get raked repeatedly by storms. 

We can't know in advance who that might be, or even if it will happen. It's just a risk to keep an eye out for. 

Burlington did make it to 90 degrees today before that batch of clouds moved in to "cool" us into the mid and upper 80s. So it was the sixth consecutive day of 90 degree temperatures.   Including this week, there have only been seven occasions since the late 1880s in which we had six or more consecutive days in the 90s

PREVIOUS DISCUSSION

Yesterday was the fifth consecutive day in Burlington, Vermont that reached 90 degrees and we actually tied a record high for the date.  

It wasn't an impressive record, as Burlington reached 93 degrees. That's just about the lowest record high for any date in July.  Most daily record highs are in the 95 to 99 degree range during the month. 

We've got one more hot day to go today, a transition day tomorrow, and then warm, but not hot weather the rest of the upcoming week. In that mix is a risk of strong storms and local flash flooding later today and tonight. 

If Burlington makes it to 90 degrees today, which seems pretty likely, it will be only the seventh time since the 1880s that the city has had at least six days in a row with 90 degree temperatures. (The longest stretch of consecutive 90-degree days was eight on August 10-17, 1944).  

We're under a heat advisory again in the Champlain and lower Connecticut River valleys, and the lower elevations of Rutland County, where the "real feel" temperature when you factor in the humidity will be in the 95-100 degree range. Actual temperatures will be 90-95. But the whole state will be hot, so it's an excellent day to take it easy. Maybe find some air conditioning. Maybe some theaters are running matinees you can check out. 

STORMY WEATHER?

The other risk is storms.  The system coming in has a history of producing rough weather. Lots of severe weather was reported in the Midwest yesterday. And in Ontario and Quebec. A tornado touched down in Quebec, about 55 miles northwest of Montreal, and a severe thunderstorm skirted the Vermont/Canada border last evening between Jay Peak and the New Hampshire border.  Hail up to the size of quarters covered the ground around Averill, Vermont. 

We have sort of mixed signals for what kind of rough weather we'll have later today, if any. There's definitely a risk of strong to severe storms scattered about starting this afternoon and going into the evening.  For the record, NOAA's Storm Prediction Center has most of Vermont under a slight risk of severe storms, which is alert level two out of five.

Out in western and central New York, there''s even a higher chance of severe storms, and they were already starting to pop out that way by mid morning.

We in Vermont will have to wait until afternoon to see any action.   Generally speaking, the peak heating hours between say, 2 and 7 p.m. are prime time for strong storms. 

You can get isolated ones in this kind of heat and humidity, but you need a trigger to get a lot more of them going, like we had on Thursday.

I question whether an approaching cold front will be close enough to give us anything widespread later today. Maybe, maybe not. Computer models disagree a bit on this as of this morning. It's something to be aware of if you have outdoor plans, so that you can quickly get into a sturdy building, or at least an enclosed car, if severe or strong storms get going. 

If any big storms do get going, there's actually quite a bit of "spin" in the air.  Winds this afternoon will be shifting in speed and direction as you go up in elevation.  That brings us the very low, but not zero chance of a brief tornado.  

Unstable looking sky over St. Albans, Vermont 
Saturday evening. That could be an alert that we
might have severe storms in much of Vermont
later today amid the oppressive heat

If that happens, or if the National Weather Service ends up having to issue a tornado warning, we'll have another rare case here in Vermont. 

It would make it the third time within a week in which either an actual tornado touches down (like in Addison, Vermont Monday) or a tornado warning is issued, like on Thursday in the Northeast Kingdom. No known tornado touched down Thursday, but there was a warning because radar detected rotation.

The best, but again, very low chance of a brief spin up would probably be in the Champlain Valley very late this afternoon or early this evening. 

Because of the loss of daytime heating, the threat of severe thunderstorms drops to near zero overnight. But the cold front will still be approaching and passing through. With all this humid air, some of these storms will have torrential downpours. Parts of the state might have several rounds of storms overnight. 

That opens up the risk of flash flooding. If that happens, it will be localized. Even though it's been dry, it's a real risk.  If some hilly or mountainous part of Vermont gets a few inches of rain in a short time, that water rushes down the slopes and can create a dangerous flash flood. 

Flash flooding is more dangerous at night, too. If you're in a flood prone area, make sure you have some sort of weather radio or device to wake you up if a storm or flash flood warning pops up.  If for some reason you're camping tonight, set things up well uphill from any brooks, streams or rivers.

The cold front will be slow, so many of us will still be dealing with humidity and downpours Monday morning. But the air will start to clear and feel fresher later in the day, especially northwest. A new threat of severe storms will develop in southern New England Monday, but Vermont should escape that. 

we During peak heating today, mid af