Lots Of Vermont Severe Weather Reports Wednesday; Today Is Quieter

If there was a (slightly) unexpected dearth of severe thunderstorms Tuesday, we more than made up for it Wednesday as a band of strong to severe thunderstorms hit pretty much the entire state of Vermont.

Although reports of wind damage were common, the real story with this one was the hail. That's not a surprise.

Temperatures aloft, several thousand feet overhead were quite chilly for this time of year. Which helped make the storms prolific hail producers.

As you can see in the photo with this post, you could see a bluish tint in the clouds as the thunderstorms approached. (I took the photo in this post as the storms approached Colchester, Vermont.)

When you see that bluish, greenish hue, you know it's going to hail. A few moments after I took that photo, it hailed a LOT. Mostly pea and dime size, but there were a few nickels and even a couple quarter sized chunks thrown in.

So much hail fell that the ground was still white in spots around Colchester nearly an hour after the storms passed.

I don't yet have time to post video of the storm. I'll try to do it in the next few days.

Also several thousand feet overhead, winds were pretty strong. The thunderstorms were able to tap into those winds and bring them to the surface. That's why we had so many reports of trees and wires down. 

Today will be much calmer, with only a few widely scattered light showers this afternoon.

The weather will remain generally unsettled for the next week or so, with an almost daily chance of showers.

Will The Death Of The Blob Spare Us From A Brutal Rest Of The Winter?

Map from the Watts Up With That
blog shows the warm "blob" in the Pacific
Ocean last year. 

A lot of blame or credit is going around for what has been a remarkably warm start to winter.

El Nino is certainly a prime suspect. Climate change probably plays a bit of a supporting role.

Something else might be at play as well: It's "The Blob." Or more precisely, the fact that the Blob is dying a quick death.

According to the Washington Post, citing weather blogger Cliff Mass, The Blob is, or was, an area of abnormally warm water in the North Pacific, off the coast of the United States and Canada and south of Alaska.

The Blob got going in the first place, said Mass, because persistent high pressure areas in the Northeast Pacific Ocean caused light winds. Usually it's stormy there, and those storms stir up waves that draw up cooler water from the depths of the ocean.

It's thought that this blob, which set up shop three years ago or so, altered weather patterns, creating a big bulge to the north in the jet stream near western North America. That steered storms away from the West Coast, contributing to a punishing drought, especially in California.

On the east side of the bulge in the jet stream, the air flow came down from the Northwest, from Canada, into the eastern third of the United States.

This northwest flow waxed and waned, of course, and sometimes disappeared entirely. But it kept coming back as long as The Blob was in the Pacific Ocean.

This winter, The Blob has cooled off to a ghost of its former self.  It's gotten stormier this winter in the northeastern Pacific Ocean, so cooler water is upwelling from the depths.

Since the water has gotten cooler, says the Washington Post, it makes that big west coast bump in the jet stream less likely.

That means, together with El Nino, storms can come off the Pacific Ocean and give California some welcome precipitation. That has been happening in California in recent days

Mild Pacific air is also able to head west to east across the nation, shunting some of those cold blasts from Canada away from the United States.

That's not to say it won't get cold. The death of The Blob just means that those traditional winter cold blasts might be less persistent than they were last winter, and the winter before that.

True, here in the Northeast, an Arctic blast started Sunday evening, but temperatures moderated quite a bit in the past day or so.  Back to somewhat above normal temperatures, anyway.

And true, there are signs another Arctic blast might come down from Canada at mid-month.

But there's still no definite sign - at least not yet - that a good chunk of the eastern United States is going to have weeks upon weeks of brutally cold, snowy weather from late January through February into March.

We had two years of that in 2014 and 2015, so that's enough.

I suppose we could end up getting another brutally rough late winter, but the death of the blob is one factor that could tip the scales against such an aggressive winter.

A wide variety of factors influence how winter weather goes. It's not all dependent on The Blob. But at least there's hope that we might not freeze quite as much as last winter.

Blue Skies, Dry Air, Breezy Days Are Rite Of Spring In Northeast. Here's Why

Pretty much blue skies yesterday in an afternoon
view looking southwest from South Burlington, Vermont
toward still snowcovered Whiteface Mountain in New York.  

Yesterday was one of those bright, brisk, beautiful, blue sky and breezy April days here where I live in Vermont. (How's that for alliteration?)

You tend to get a number of days like this during the early and mid spring in much of southern Canada, the Northeast and the Great Lakes region.

Humidities in these air masses are very low, so the air has a very clear, haze-free quality to it. With plants not yet growing yet, the dead stuff from last year dries out quickly, raising the risk of fires.

There was a red flag warning in much of New England yesterday because of this risk. But otherwise, it was a perfect day.  

This kind of weather happens because areas of high pressure, the kind that was over the Northeast yesterday, tend to have dry, sinking air that discourags clouds. So it probably would have been a pleasant day no matter what time of year that high pressure system decided to come through.

However, the air was especially dry yesterday, which came about for reasons in addition to the overhead weather pattern.

Trees in the region, and in southern Canada, where the air mass came from, haven't leafed out yet. Leaves emit moisture into the air, so had everything been in bloom, the humidity might have been a little higher than yesterday's desert-like levels.

There might have even been a few extra clouds decorating the blue sky had things been leafy.

On top of that, the Great Lakes, and all the lakes in southern Canada and in our region, were either colder than the air, or still frozen.  This set up is common in the spring, as the air responds to the strengthening rays of the sun faster than water does.

Warmer air over colder water tends to prevent rising air currents from bodies of water, such as lakes. So they are not able to add any appreciable moisture to the air.  Less moisture equals fewer clouds, and more blue sky. Which is what we had yesterday.

This is in contrast to New England's incredibly cloudy late autumns and early winters. Then, the water in the Great Lakes and other bodies of water is warmer than the air, since the summer weather in the previous months had just warmed them up

When the water is warmer than than the air, updrafts tend to form and moisture in the water lifts up into the air, tending to form lots of clouds.

But it's spring, so the lakes don't do the moisture thing, since they're so cold.

This time of year, we in the Northeast have to rely on larger scale storm systems to supply the April showers that will (hopefully!) bring us those May flowers.

Luckily, there are several chances of showers over the next week or so in the Northeast. Nothing huge, but enough to keep encourage those trees to bud and early season flowers to bloom.

Sunday's Storms In Vermont Created Amazing, Sometimes Rare Clouds

Many thunderstorms, some of them severe, raked Vermont and parts of northern New York Sunday.

A roll cloud precedes a weakening thunderstorm
approaching St. Albans, Vermont Sunday evening.  

It was part of a massive severe weather outbreak in the eastern third of the United States that produced damaging tornadoes in Tennessee, Kentucky and elsewhere, wind damage, hail and flooding.

There were 378 reports of severe weather across the nation Sunday, including six tornadoes.

The damage wasn't so widespread here in the North Country, with reports of flash flooding near Plattsburgh, N.Y, one-inch diameter hail in Ferrisburgh, Mendon, Westford and Williston, Vermont, and tree damage in places like Charlotte and Peacham, Vermont.

Outbreaks of summer thunderstorms often create the most interesting clouds imaginable, and Sunday's bout of storms did not disappoint.

I was treated with the rare sight of a well developed roll cloud preceding a non-severe thunderstorm rolling toward my home in St. Albans, Vermont.

The roll cloud in St. Albans, Vermont Sunday evening
scrapes against a low hill as it crosses the community.  

Later, the setting sun, lit up some mammatus clouds, a relatively rare sight in the Green Mountain State, and a sign somebody off to my east or northeast was getting a really nasty storm.

I also saw some shelf clouds yesterday, too.

I'd better explain my terminology.

A shelf cloud looks like just that, a low, dark, shelf like feature in the front of a thunderstorm.

When you see a shelf cloud, it's time to take cover, because the parent thunderstorm is probably severe. When the shelf cloud goes overhead, you're likely to get  really nasty burst of strong, damaging winds and maybe some hail.

You'll see just after the middle of a time lapse video a shelf cloud Sunday evening over Malletts Bay, Colchester, Vermont.

Mammatus clouds are lit up by the setting sun
over St. Albans, Vermont Sunday evening.  

A roll cloud like the one I saw yesterday looks dramatic and scary to people unfamiliar with them, but they really aren't dangerous at all.  

They're usually caused by a downdraft from a decaying thunderstorm that lifts a bit of warm and humid air from the surface.

The air rises and curls toward the dying thunderstorm, and you get something that resembles maybe a weird, horizontal tornado.

When the roll cloud moved overhead in St. Albans, we had a wind gust to perhaps 20 mph, followed by a brief burst of rain. Nothing scary.

The decaying thunderstorm that caused my roll cloud was ceding energy to a strengthening thunderstorm to my south, near and to the northeast of Burlington, Vermont.

Another view of the mammatus clouds over
St. Albans, Vermont Sunday evening.  

That storm complex continued toward the northeast. When it got to near St. Johnsbury, in northeastern Vermont, it had become quite strong and was producing a few damaging wind gusts and probably some hail.

As the sun was setting, it lit up the anvil shaped top of the thunderstorm, way up there maybe at 30,000 feet above sea level.

The anvil top curved back many miles toward the west, as they often do in strong storms. The top of this thunderstorm was easily visible from my house in St. Albans, 50 west of the storm's core.

The anvil top of a thunderstorm consists of moisture that spreads out as its upward momentum dies off.

Developing thunderstorms early Sunday afternoon made
for a pretty sky over Lake Champlain near South Hero, Vermont.  

Sometimes, some of the ice in the air within this anvil starts to sink, giving you those pouches that you see in mammatus clouds.

Mammatus clouds are always connected to thunderstorms, and the thunderstorms they're connected to are often, but not always strong or severe.

But if you see mammatus clouds overhead, like I did Sunday evening, don't worry. Usually, they're on the back side of a storm, which has already gone by.

Of course, days with thunderstorms create more routine, but very pretty and interesting cloud patterns.

It was fun to watch thunderheads bubble up to become storms during the course of the afternoon. They you could see big blasts of rain come out of the storms, then a rainbow to finish it off.

A thunderstorm dumps a heavy load of rain in this
view from Lake Champlain looking toward Colchester
and Burlington, Vermont.  

Very pretty.

Today, there's more storminess in Vermont and New England.

There could be some interesting clouds again amid the possibly strong storms in eastern Vermont, New Hampshire and Maine.

But places more to the west will likely see rain and a dull overcast. Not nearly as interesting as Sunday.

Here's that time lapse, produced by Dan Russell, of thunderstorms in Malletts Bay, Colchester, Vermont to give you another glimpse of Sunday's stormy, changeable and fascinating skies:

The Season Of The Flash Flood

Flash flooding  covers a road near
Jericho, Vermont on July 4, 2013.  

In much of the nation, we've entered the season of the flash flood.  

Yes, flash floods can and do occur any time of year in almost any part of the country. But summertime, especially from now on into September, is when you are at most risk of such floods.

Right now, there are flash floods, or the threat of such, going on in parts of the country. The area in and around Memphis, Tennessee is having big problems this Sunday morning as torrential thunderstorms fill underpasses and creeks with water.

In the Upper Midwest and northern Plains, soaked by repeated rounds of bad storms since May, more thunderstorms threaten renewed flash flooding over the next few days. 

True, it's the hottest, sunniest part of the year in many parts of the country, too. So things dry out fast. So how do you get floods?

Easy. Weather systems move more sluggishly than they do in the colder months. A collection of thunderstorms might move slowly over a particular area, or not move at all. The result is inches and inches of rain, and a flash flood.

We had that here in Vermont last summer, several times during June and the first part of July. It was a very wet early summer, and slow moving storms causing several destructive flash floods in different sections of the state.

The hot, often humid air of summer can hold a LOT of moisture. A thunderstorm or complex of storms can collect much of this wetness and dump it onto the land below, and there you go, another flash flood.  

Another motorists takes a chance with
a flash flood in Richmond, Vermont in June, 2013.  

In the southwestern United States, the heat causes the air pressure to fall. Gradually, that draws in moisture from the Pacific and Gulf of Mexico to places like Arizona and southern Nevada, and surrounding areas.

This moisture sets off thunderstorms. The desert landscape can't hold onto the water that pours from these storms, and yes, you get a flash flood.

Finally, later in summer, the tropics get active. A tropical storm or hurricane moving inland can drop huge amounts of rain and cause a flash flood. In fact, inland floods are arguably the biggest threat from tropical storms and hurricanes.

Where I am in Vermont, we're too familiar with this phenomenon, too. In August 2011, Hurricane Irene moved into New England. By the time it got into Vermont there wasn't much wind, but boy was there rain!  It turned into a chaotic flood, easily among the Top 5 natural disasters in the Green Mountain State's history.

These tropical storms, or more accurate, their remnants, can set off floods a long, long time after they've seemingly dissipated.

In 1995, Tropical Storm Dean hit Texas with little fanfare. An area of disturbed weather, the remnents of Dean, slowly crossed the center of the country, where if finally collided with a cold front over northern Vermont.

The result was a huge, destructive flash flood, especially in the Lamoille River basin.

Flash floods, as is obvious, come on fast. If you see water going over a road, or any kind of flood threat when you're out and about, remember that hoary but true National Weather Service admonition: Turn around, don't drown.

You Don't Need A Sunny Day To Melt In the Heat

The past couple of days have been rather gray and gloomy in Vermont. A glance out the window could make you think there's a little bit of chill pre-autumn dampness in the air.

Fog,  haze and dense clouds in St. Albans Tuesday
morning gave the atmosphere a chilly, damp
appearance, but it was actually oppressively humid.  

Think again. Anyone who has stepped outside over the past 48 hours knows it is humid as heck out there.

Which proves you don't necessarily need a blazing summer sun to feel like you're melting in the summertime.

The weather is deceptive. If you don't do much out there today, you might stay relatively comfortable. Exert yourself a wee bit, and the sweat starts pouring off you.

To get a sense of whether you'll be uncomfortably warm when you go outside, it's not enough to just look at the temperature. Yeah, if it's 95 degrees, it's hot, no matter how humid it is.

But days like yesterday and today, when the temperature was "comfortably" in the 70s, are a reminder to look at the dew point.  The dew point is essentially how far the temperature has to drop before the air is saturated. You get dew and fog if the temperature and dew point match. But usually, the actual temperature is warmer than the dew point.

If the dew point is above 60 degrees, you start to feel the humidity. Above 65, it's in your face. Above 70, and OMG!! I'm mellltttting!!!!!.

As I write this early Tuesday afternoon, the temperature in Burlington is 78 degrees. Not bad. But the dewpoint is 68. Wicked sticky.  The dewpoint has been at or above 65 degrees in Burlington since early Monday afternoon. It's also humid throughout the rest of the Northeast.

The high humidity is kind of pooling near the Great Lakes and northern and western New England because we're near the eastern boundary of a blazing Midwestern heat wave. Weather disturbances like to ride along the edges of heat waves, and that's what's been happening since early Monday, and what will keep happening the rest of the week.

It tends to be on the humid side along the path of these heat-edge seeking weather disturbances.

So we can expect a fair amount of clouds, but some sun between the disturbances. There is a risk of a shower or storm occasionally, and it will stay humid into the weekend. But the humidity might tend to wane just a little as we go through the week.

And signs are the humidity will really diminish by early next week. We'll be into September by then, after all. Time to start thinking about the crisp, decidedly not humid days of fall.