Saturday, October 16, 2021

Strange Vermont October Warmth Went Out With A Damaging Bang Today

UPDATE 5:30 p.m.  SATURDAY

Maybe kind of hard to see just from this screen grab of 
a video, but trees behind my house in St. Albans, 
Vermont really being tossed by strong winds as today's
severe warned squall line swept through 
That line of storms as of this hour is entering the Connecticut River Valley and will be out of Vermont soon.  


Pretty dramatic storm as it came through St. Albans, Vermont, as observed at my house, but no damage here. 

 Now my road (Route 36) is closed.  The sheriff deputy blocking the road didn't have details, but said a tree fell on a car and power lines, and a house also caught fire in the incident. 

He had no word on injuries, or the extent of damage to the house involved. 

Elsewhere, downed trees blocked at least two roads in Essex, Vermont. As of 5:15 p.m., about 1,600 Vermonters had no electricity due to the storms. 

I'm sure more damage reports will filter in this evening, but thankfully, this was no blockbuster storm. At least for most of us. 

Except for perhaps far eastern Vermont, the severe weather threat is over. Widespread showers will continue well into this evening as temperatures slowly fall.  


UPDATE 12:30 PM SATURDAY
NOAA's Storm Prediction Center has chances for
tornadoes in parts of the Northeast. The highest,
but still relative low risk is in brown areas 
of the map.

As of shortly past noon, the chances of severe storms at least in western Vermont and eastern New York seem to be ramping up some.  

NOAA's Storm Prediction Center has upped the chances of a brief tornado in the Champlain and northern Hudson Valley late this afternoon, with the caveat that the chances of that happening are still quite low. 

According to the SPC's updated map, there's a 5 percent chance of a tornado within 25 miles of any spot in the Champlain Valley. 

That's the brown area of the map in this post.  Earlier, the SPC had given all of western Vermont and some adjacent areas a 2 percent chance of a tornado happening with 25 miles of a given location.

It's a low risk for sure, but it's unusual to have that high a risk in Vermont, especially in October.  And the map is awfully similar to the one in March when we had that tornado in Middlebury.  I'll repeat my statement from this morning that history probably won't repeat itself, but it's still interesting.

There's plenty of fuel for strong storms today.  As of noon, the temperature in Burlington was 76 degrees with a very high dew point of 65 degrees.  That's pretty much sufficient to help initiate storms. There are breaks in the clouds south of Burlington, which will help destabilize the air further. 

On top of that, the winds aloft are increasing in speed, and they're changing directions with height. 

Showers have been pretty persistent in the northern Champlain Valley, pretty much north of Milton, so I wonder if that will suppress the severe threat a bit in Franklin County.  I'm not sure, but that's a possibility

Severe storms are possible anywhere in Vermont as that line comes through later today ahead of the cold front. A severe thunderstorm watch is up for all of Vermont except the farthest reaches of the Northeast Kingdom until 7 p.m. this evening. 

If I were forced to predict the most likely place for a severe storm or brief tornado, I'd suspect it would be very roughly along a line from Fair Haven in western Rutland County north to Burlington. 

By far your best bet is to have an ear to a NOAA weather radio or any of our fine meteorologists at local television stations. The TV meteorologists will break into regular programming if there's any dangerous weather to warn us about. The National Weather Service office in South Burlington have their eyes firmly on this.

So just pay attention and do whatever they tell you to do, like take shelter in the event of a storm.

Also know that in the unlikely event of a tornado, the type of spin ups in this situation are often hard for meteorologists to see in advance. They'll spin up between radar scans, then disappear before the next radar scan goes through. That ups the chances that there might not be a warning.

The meteorologists will highlight any suspicious areas for you. But if you see menacing clouds, even if there's no weather warning, it will probably be best to get into a pretty sturdy building, just in case. 

Also note that most of us won't see severe, damaging weather today, but some of us might. Be weather aware! 

If there are any tornadic or severe thunderstorms, they will be right around kinks in the line of storms expected to move through later this afternoon.  

PREVIOUS DISCUSSION

The long warm spell we've had this month is still scheduled to come to end today with a bit of a bang. 

Some of you might have already heard some banging early this morning as the storm system's warm front produced a few thunderstorms along with the showers that passed through. 

Later today, expect some storms to be strong or even severe as they come through Vermont. There's even a very, very low, but not zero chance of a tornado in western Vermont today. Very strange for October! 

Speaking of strange, I do have to pause here and remark about how warm it's been this month, especially at night. The average low temperature in Burlington so far this month, through yesterday, is 53.3 degrees. That's more than 10 degrees warmer than average. 

There's already a lot more leaves on the ground in my 
St. Albans yard as winds pick up this morning. A lot
more of those orange leaves will be on the lawn by 
tonight with windy weather today, and possible
severe thunderstorms late this afternoon or evening.

Days have been almost as warm. Remarkably, today with be the sixth consecutive day of highs in the 70s in Burlington. I've seem stretches of weather like that in Vermont in July. 

We have had one of our warmest, if not the warmest first half of October on record. 

The summit of Mount Mansfield is still waiting for its first frost of the season, by far the latest on record. Overnight lows up there have been in the 50s for four straight days.  The summit of Vermont's tallest mountain does look like it will see its first freeze of the season Sunday and/or Monday night. More on that in a moment

We will have yet another warm and oddly muggy day here in Vermont today before that cold front makes it into the state later today and this evening. There will be a difference from previous days, though:  Unlike the relatively calm winds of the past week, gusty south winds have developed, especially  in the Champlain Valley.

It won't rain much between this morning and when the cold front gets here later today. There will be a few scattered showers around through mid afternoon, but they won't amount to all that much. We'll see spots of sun, and lots of blowing leaves as winds gust to 30 mph in many places. Gusts could reach 40 mph in some areas in the Champlain Valley. 

Then the cold front comes. The line of storms has a history of tornadoes and possible tornadoes in Ohio, Pennsylvania and western New York.  So you see it has some power to it. 

NOAA's Storm Prediction Center has upped the risk for severe storms from marginal, which is the lowest category on the hazard scale, to "slight" in western Vermont,which is level two on that scale. Eastern Vermont remains in the marginal category. 

Slight risk means they're expecting scattered severe thunderstorms.  That means a few spots could get winds of 58 mph or greater. Those damaging straight line winds are the most likely outcome of this weather front in Vermont.

Still, this cold front has some similarities to the one that produced a tornado in Middlebury back in March. It's highly unlikely this history will repeat itself, but it's been such a bizarre year that anything seems possible at this point. I can't rule out a brief spin up with this front. 

 The gusty rough weather won't last long in any given location, since the line of storms is pretty narrow. But many areas could see gusts up to 50 mph or so, and a few places will get blasted by gusts even higher than that.  I do expect a few reports of damage to trees and power lines this evening. 

 The downpours won't last long enough to cause flooding, except in urban areas where fallen leaves will have clogged storm drains.  Some street flooding is possible in some towns.

 As for timing, the best guess is the line of downpours and storms will arrive in the Champlain Valley around 5 or 6 p.m. and be in the Connecticut River Valley by around 8 or 9 this evening.

This type of severe storm threat is very unusual in Vermont for this late in the season, I have to say. 

 THE BIG CHANGE

Forecasters have gotten a little more bullish on the cool down after this cold front goes by.  It still won't be anything strange for mid-October, but after such warmth, it IS a shock to the system.

Sunday will be kind of decent, actually.  Partly cloudy skies, a brisk northwest wind, with scattered afternoon showers.  Highs will be in the upper 50s, about normal for this time of year.

It gets even chillier for a couple days after that. Again, nothing odd for this time of year, but still super noticeable. 

I see the National Weather Service in South Burlington has mentioned snow in the forecast for the first time this season in relatively low elevations. 

Parts of the Northeast Kingdom and other chilly areas of northern Vermont could see some wet snowflakes mix with the scattered showers Monday night and Tuesday. We might also see a glimpse of snow capped Green Mountains by Tuesday. 

It'll warm up a little in the middle and end of this week, but it will still be much cooler than it's been lately.  I think I can finally say summer is over.  But I've been surprised before. 

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