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| Some spots in the yellow area of this map could get severe thunderstorms on Wednesday. The principal risk from these storms is strong, straight line winds. |
Though forecasts can still change and go the other way, as of early this afternoon, the threat of severe weather here in Vermont tomorrow seems to be increasing, at least according to the latest forecasts.
NOAA's Storm Prediction Center as of early this afternoon is still targeting the area you see on the map for at least a slight chance of severe thunderstorms Wednesday afternoon.
However, depending on what new data between now and tomorrow morning read, the Storm Prediction Center might upgrade the risk level to "Enhanced" for eastern New York and Vermont.
The scale of risk from the SPC is marginal, slight, enhanced, moderate and high. Enhanced means more than just one or two storms. There may be a fair number of severe weather reports in such a region. We'll see how that sugars off.
Worse, there are somewhat increased signs that rotating thunderstorms could get going in the region, especially, perhaps in the Champlain Valley. By the way, not all rotating thunderstorms produce tornadoes. Most don't. But if a storm rotates, you have to watch it carefully because it does have some potential of creating a twister.
In the Champlain Valley, it's possible a supercell thunderstorm or two could get going ahead of the main line of storms. That would mean a slight tornado risk. Also, some storms along the main line of bad weather could create some spin ups.
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| This forecast model, called teh HREF depicts rotating thunderstorms in norther Vermont Wednesday (those are the grey, blue and green streaks circled) While this might or might not happen, rotating thunderstorms can sometimes, but certainly not always, spin up a tornado. |
One forecast model, called the HREF, depicts rotating thunderstorms - with the possibility of a tornado - Wednesday afternoon. Also, given the overall wind direction, the orientation of the Champlain Valley could locally increase the spin of some storms.
This is just one of many forecast models. Don't hang your hat on that one. Meteorologists will be looking at a slew of computer and human forecast to determine what risk we have tomorrow, if any.
Besides, there are factors that argue against storms strong enough to produce a tornado.
There is some question as to whether enough instability will be present to create such a scenario.
All this isn't meant to be a scare tactic. The chance of a tornado tomorrow is still very low. Even if a tornado forms, 99 percent of us wouldn't get hit by it. The main threat from any thunderstorm tomorrow would be damaging straight line winds. Which can be almost as bad as a tornado, really.
All I'm suggesting is you should keep a particular eye on the weather Wednesday afternoon and evening and be prepared to get inside really quickly if threatening weather approaches. This ain't Oklahoma, so we're not all going to blow away tomorrow.
The number of tornadoes nationwide has been low this year. However, in the Northeast, tornadoes have been unusually frequent in 2018. Still, no tornadoes have been reported in Vermont this year. Which is a good thing. I had better stay that way but like I say, eye on the sky, please.
PREVIOUS DISCUSSION:
We're off to a good start with our shift into autumn weather here in Vermont. We need to get rid of a drought hanging around, and we're chipping away at it.
Last Friday, we had a good soaking in northern Vermont for the first time in ages. We had to put up with a lot of wind and fallen tree branches, but it was worth it.
Today and tomorrow, we face more wind, but also more rain, which is great. The possibility of severe thunderstorms on Wednesday isn't so great, but we'll get through it.
The summertime pattern that featured near constant, flooding downpours from New Jersey to Virginia, but high heat and drought up her in the North Country, has totally broken down, finally.
Autumn can very often be a battleground between the lingering heat of summer to the south, and the building winter chill up north. Lately, that battle ground is running from the Midwest, through the Great Lakes and into the Northeast.
When you are in this seasonal battleground, chances are high you will get storminess and precipitation.
The latest wet, welcome slap is giving us our chilly, rainy I-want-to-hibernate Vermont weather today. It's a warm front, but of course it won't get warm until the front passes by. The warm front is lifting air ahead of it like a snowplow would push a snowbank up and ahead of it.
Rising air like this means rain, which is why we're getting this nice, steady rain today. Those of you in the Northeast Kingdom who have not seen the rain will get it soon.
The warm front will pass by tonight, and the showers will become lighter and scattered. Overnight will actually be warmer than this afternoon because of the passing of this front.
On Wednesday, we'll get into a zone of warm, humid air. Don't worry, it won't be like the oppressive, high heat we so often experienced in the summer. Instead, temperatures will be well into the 70s, and you'll definitely work up a sweat with any physical activity outdoors. It will be muggy.
Much like last Friday,a cold front will be approaching from the west. Last Friday's cold front caused mayhem in Ontario and Quebec, with an outbreak of severe weather and strong tornadoes. Those storms last Friday weakened dramatically by the time they got to Vermont. It was night, so there was no sun to destabilize the air.
This time, tomorrow, the timing of the cold front is such that Vermont could be in zone of maximum strength thunderstorms. Again, don't worry. Tomorrow's storms will not be nearly as bad as those that struck Ontario and Quebec last Friday.
Still, we are at risk of some severe thunderstorms. Some sun will probably break out here and there, helping to destabilize the atmosphere. Strong winds will be blowing high above us. The speed and direction of these winds will shift depending upon how high above the earths' surface you are.
That's a recipe for severe thunderstorms.
There's still no guarantee the severe storms over Vermont and much of the rest of the Northeast will develop. Things have to come together just right. If severe storms DO develop, not everybody will get them.
However, some of us could easily face the prospect of strong, damaging winds with a few of the thunderstorms that pass over Vermont Wednesday afternoon and evening.
At this point, NOAA's Storm Prediction Center is thinking the greatest potential for damaging winds in any thunderstorms would be across eastern Pennsylvania, eastern New York and western New England. I do expect some adjustments to this forecast. There are always changes to predictions when there's a dynamic situation such as this.
Because of changing wind directions with height, there is a very, very remote chance of a brief tornado, but definitely don't count on that. The principal risk from the storms will be strong, straight line winds in a few areas.
My advice for you: Do whatever you planned to do tomorrow, unless it involved boating on the lake or hiking in the mountains. I'd postpone that for a day. For everybody else, just keep one ear on your weather radio or however else you get weather warnings.
If your area is one of the lucky ones to fall under a severe thunderstorm warning, do the usual precautions: Get indoors, and stay away from the windows until the storms pass.
Looking ahead, we remain in the weather battleground. That means storms will pass by fairly close to us, repeatedly swinging warm and cold fronts over us. Things will move right along, so rainfall in any one of these episodes won't be particularly heavy, and won't last all that long.
Which is OK. You don't want the rain all at once. The ground will gradually get wetter with each passing weather front, and that's fine by me.
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