On Flood Anniversary, Vermont Risk Of Flash Flooding Increases A Bit, Still Not Nearly As Dire As Last 2 Years

Parts of Vermont and northeast New York got a slight
bump up in the risk level of severe storms. Earlier
forecasts had us in the dark green marginal risk
meaning isolated instances of damaging winds.
It's now "slight" meaning scattered instances, not
just isolated cases of bad storm winds. 

UPDATE 1 PM THURSDAY

NOAA's Weather Prediction Center has increased the risk level for flash flooding in Vermont this afternoon and evening. 

Instead of a marginal risk of isolated instances of flash flooding, (level 1 out of 4 risk) we're at what is known as slight risk, which is level 2 out of 4 in the risk categories.

This means instead of just a 5 percent chance or so of seeing flash flooding within 25 miles of your location, there is now a 15 percent chance or even somewhat better than that chance of seeing flooding in that radius.

This is because the developing storms are slow movers. We could see pockets of two to four inches of rain in a few spots. 

Flash flooding could happen anywhere around Vermont today, , but I still think the highest chance of flash flooding is in the Northeast Kingdom, where there have been local downpours all morning. 

Ominously, a flood warning already had already been issued around the town of Orleans in the Northeast Kingdom

I'll emphasize that we're still NOT going to see anything nearly as widespread or destructive as we did on July 10-11 last year or the year before. 

Most of us will be just fine today and tonight, and most of us will still see much less than two inches of rain.  An inch of rain, if you manage to get that, won't cause any flood issues. 

Updated risk map increases the flash flood threat in
Vermont a bit to slight, level two out of four on the
risk scale, as you can see below, it was earlier
just marginal, a level one out of four on the risk scale,

But I do think there will be some scattered areas of trouble in Vermont today. This could be the third year in a row with flood issues on this date. 

Stay tuned to your weather radar through the day and into the evening to receive warnings of local flash flooding or spots where severe thunderstorms could trigger damaging winds. 

PREVIOUS DISCUSSION

I guess July 10 and 11 have become a weather tradition in Vermont. 

It seems either something really bad happens, like the big floods of July 10, 2023 and 2024, or everything is fine, but something interesting happens with the weather. 

Not every July 10 and 11 is weather weird, of course. Historically, most of them are pretty routine, like any date of the year. But the dates often bring at least something vaguely noteworthy. 

The chilliest temperature of July, 2022 in Burlington came on July 10.  The low of 50 was not all that cold for July, but is still the coolest July temperature since 2015. July 10, 2020 was the hottest day of the month, with a high of 95 and a low of 75 in Burlington.

When I was a kid, July 11, 1976 stands out as one of the worst local flash floods I've ever seen, striking parts of Rutland County. Going way back to 1888, it snowed like hell for a time on the Green Mountain summits. 

As mentioned in my Wednesday post, today won't be a repeat of the hell we went through in 2023 and 2024. 

Today will just bring us some interesting doses of showers and thunderstorms.  Some of which seem destined to cause local spots of trouble here and there in the Green Mountain State.   So you'll need to stay on your toes. 

THIS MORNING'S SET UP

An area of heavy rain that caused flash flooding in the Mid-Atlantic States last evening moved into southeast New England today, where flash flooding from up to six inches of rain hit earlier this morning 

We don't have to worry about those annoying downpours,  as they will keep moving off to the northeast off the New England coast.

But here in Vermont, it was already a bit interesting as of 8 a.m. There were already some widely scattered pinpoint, slow moving downpours around the state. 

That's a hint right there we will have no trouble generating a bunch of showers and storms during the day today. It's hard to know exactly how each storm will develop and move, but what follows is a decent guess. 

Flash flood risk in Vermont is still marginal, meaning at
most isolated instances os flash floods. The yellow areas
have a somewhat higher risk of flash floods. 

Breezes going up the slopes of the Green Mountains should generate storms along those mountains. Maybe pretty early in the day, before noon.  Those should then drift eastward into the Northeast Kingdom and the Connecticut Valley.

The rest is complicated. The storms could generate outflow gusts that will interact with other weak disturbances coming in from New York State, which would then drift eastward into the Champlain Valley later this afternoon. 

 Eventually, they'll head through the Green Mountains into the eastern Vermont toward evening.

Other random storms could pop up just about anywhere else during the day and evening today.  

Most of the storms won't be super awful. However, the Storm Prediction Center has upgraded much of Vermont and northeast New York  to a level two slight risk level for severe storms, which means scattered instances of severe storms, Until earlier this morning, the risk forecast was lower with only a marginal risk of isolated instances of severe storms.  

If severe storms form, they'll produce damaging winds in a few spots. There's also a risk of damaging hail, but that risk is pretty low. 

The storms will also move sluggishly.   With heavy downpours. If you're unlucky enough to have a storm stall over year, or get hit by several of them, there could be a local flash flood problem. NOAA's Weather Prediction Center is still watching the current marginal risk of local flash floods.  

As of today, it would take probably two inches of rain within three hours to start flash flooding in most parts of Vermont.  A few isolated places in the state could see up to three inches in that time frame, hence the small risk of those flash floods,

I'll emphasize that the vast majority of us will see much less than three inches of rain today, which is why we won't have any widespread problems with high water. Still, take any flash flood warning seriously. If you're under such a warning, stick to high ground. Don't drive over a flooded road, as it could be washed away or undermined.

A flash flood could develop anywhere, but I'd say they'd happen in the Green Mountains or Northeast Kingdom. 

You'll want to have a weather  radio with you today, or at least some way to receive severe thunderstorm or flash flood warnings, just in case. 

But again, Ill stress that meteorologists expect nothing close to the scale we saw last year and the year before.  

HEAT

It's humid out there, and it will stay that way. The little boundary in New York that's helping to set off today's storms isn't really a cold front. It will have gone by us tomorrow, so we expect storms to be few and far between on Friday.

Temperatures are  going to go up again, too. The clouds and storms should hold temperatures today in the upper 70s eastern Vermont to low 80s west.  Starting tomorrow and on through at least next Wednesday, daily highs in Vermont should get into the mid and upper 80s. With a few 90 degree readings thrown in here and there.

The humidity will stay high, so nights will be stuffy too.  Not a good week coming up if you don't have air conditioning, I'm afraid.

Given the heat and humidity, there's a chance of a scattered storm or two each afternoon and evening, but most places will be dry most of the time. The best chances of storms at this point look like they'll be around later Sunday and maybe Monday.  

Sunday Evening Update: Now 29 Consecutive Vermont Weekends With Precipitation. Record Could Be Tied Next Weekend

Radar image from 1p.m. Sunday shows some small
showers in the Champlain Valley, including one that
deposited just 0.01 inches of rain at the National
Weather Service office in South Burlington. 
That makes this the 29th weekend in a row
with at least some precipitation, The record
for the most consecutive such weekends is 30.

 Shortly after 1 p.m. today, a  dying shower passed over the National Weather Service office in South Burlington. 

The shower deposited just 0.01 inches of rain, so little you'd hardly notice it.  No biggie.

Except in one respect it was, 

Contrary to many weather forecasts ahead of the weekend, the streak of consecutive Vermont weekends with rain has not ended. 

As measured in Burlington, we now have had 29 consecutive weekends with at least a trace of precipitation. 

The record for most consecutive weekends with rain or snow is 30,  from September 1 1934 to March 23, 1935.

On Friday, it looked like it this weekend would be a lock for no rain.  High pressure that brought us our generally sunny, comfortable Fourth of July would slowly slide off to the east, ensuring it would warm up but also keep any frontal systems with their showers at bay. 

That high pressure delivered on the predictions that Sunday would turn out partly sunny, hot and humid.  However, the high pressure was far enough south so that the subtlest disturbances in the atmosphere could work with the humidity to pop up some widely scattered shower and thunderstorms. 

Breezes off of Lake Champlain can sometimes trigger scattered showers and storms in humid weather. They create a sort of mini "cold front" at the boundary between the cool lake breeze and hotter inland air.

That appears to be what happened on the western shore of Lake Champlain before 1 p.m. Sunday. A few small downpours formed on the New York side of the pond, along the boundary between lake breezes and the hot and humid land. Prevailing winds then took these showers eastward across the lake. 

The showers weakened as the crossed the lake, having lost that boundary between cool and hot. But the one of them held together long enough to deposit that bit of rain at the National Weather Service office in South Burlington.  

After the shower departed, the sun came back out and temperatures rose above 90 degrees for the fifth time so far this summer. 

Before climate change, Burlington used to average about four or five 90s per summer, but in the past two or three decades, days of 90 degree heat have become more frequent.  

It's too soon to know whether it will rain next weekend to tie the record, and then rain again the following weekend to break it. Early indications suggest there might be some weather disturbances around next weekend that could create some more hit and miss showers. 

As always we shall see! 

Monday's Severe Weather Outbreak Tempered, More Severe Storms Northeast Today, Vermont On The Margins

Big area in yellow and especially orange have a risk
of severe storms and maybe a couple of tornadoes
today. Areas in dark green, including much of
Vermont, just have a marginal risk of an 
isolated severe storm or two. 

 Monday's anticipated tornado outbreak in the upper Midwest left a trail of damage, but doesn't appear to be nearly as bad as it could have been.  

That's a rare bit of good news in what has been an active, deadly tornado, severe storm and flood season in the United States.

Through April 27, there has been a preliminary count of 668 tornadoes this year in the United States. The average count for that point in the year is 475.   

So far, 2025 has had more tornadoes through April 27 than all but one year since 2010. (The year 2011 was insane, with 1,262 tornadoes through April 27).

At least a couple tornadoes touched down in southern Minnesota and in Wisconsin, leading to trails of damage but no serious injuries. 

It's not done, of course, as today is still forecast to be an active severe weather day. Today's threat extends in a long line from northern and central New York southwestward all the way to western Texas.

In the line, the highest risk of damaging storms, large hail and a few tornadoes are in central and western New York, northwest Pennsylvania, Ohio, and in northern Texas.

New York is the weird one. It's a new tornado alley in the Northeast. The state had a record number of tornadoes in 2024.  New York has already had a couple tornado warnings this year, though I don't have any information on whether any touched down. 

I give decent odds that at least a brief twister could touch down today in western New York 

VERMONT THREAT

The expected weather in New York today might make you wonder if that severe weather will sweep over into the Green Mountain State. 

Turns out, here in Vermont, we're in the margins of the severe weather threat. 

New York State, all the way from Buffalo to the Adirondacks, should be in a relatively sweet spot for severe storms today.  Dew points, a measure of how humid it is, should get into at least the low 60s, which would be fuel for strong storms. 

The right combination of strong upper level winds with direction changing with height will come during the afternoon. That's when the sun's peak heating hits. Those winds and the instability the sun's heat creates also improves chances of severe storms.

Here in Vermont, the conditions won't be quite as good. 

It'll get plenty warm, with some towns possibly touching 80 degrees for the first time this year.  At least early in the day, sunshine will further destabilize the atmosphere. But the humidity won't be quite a high in Vermont as it will be in New York. 

Also, the strong and veering winds in the atmosphere we'll see in New York won't be quite as strong or organized over Vermont.  Plus, most of the storms would arrive here after the peak heating of the day, so the instability in the air will have been starting to decrease by the time the weather system makes it into Vermont. 

The result will be likely a broken line, or broken lines of storms migrating in from New York late this afternoon and this evening weakening as they do so. 

Some of those storms might still have some oomph left to them when they make it to western Vermont.  

The northwestern half of Vermont is in a marginal risk zone for severe storms, or level one out of five on the threat scale, with five being the scariest.  Marginal risk means there might be isolated instances of damaging thunderstorm winds, but nothing widespread. 

Unlike in New York, there's no threat for any tornadoes today or this evening in Vermont. 

Of course, lightning is always dangerous, so you'll want to get indoors when and if you hear thunder. Some of the storms might have some briefly heavy downpours and small hail, too, but this won't be nearly enough to cause damage or create flooding problems. 

LOOKING AHEAD

Wednesday is looking bright and breezy and quite cool, with highs barely in the 50s for many of us. 

In warmer Vermont valleys, the growing season, at least in the opinion of the National Weather Service,, starts Thursday, May 1. 

As a result, the frosty weather Wednesday night will likely prompt a smattering of frost advisories for parts of Vermont Thursday morning.  Thursday afternoon will warm up nicely, though. 

The next storm is due Friday with likely showers and maybe some thunderstorms. 

Severe Weather/Tornado Outbreak Upper Midwest Today, We In Vermont Could See Severe Storms Later Tuesday

Widespread severe storms and likely tornadoes are 
likely today, especially in red and orange areas 
on this map. 

The Upper Midwest if bracing for a rough day today of potentially strong tornadoes, giant hail and destructive winds as the weather set up is almost ideal for a severe weather outbreak in that neck of the woods. 

That severe weather is forecast to some extent migrate toward the Northeast, maybe affecting Vermont later tomorrow. More on that in a bit. First, today's Midwest threats.

TORNADO RISK DETAILS

Even before our storm really got going, things were looking ominous Sunday evening. Some supercells spit out a handful of large tornadoes in western and central Nebraska.

Some pretty strong storms were ongoing early this morning in eastern South Dakota and southwest Minnesota.

These are just a preview. The main show will get going this afternoon

The area under the biggest threat for dangerous weather today includes most of Wisconsin and Iowa, southern and central Minnesota and northwest Illinois.  

Major cities most likely to be under the gun are Minneapolis-St. Paul, Minnesota; Madison, Wisconsin; Des Moines, Iowa and Rockford, Illinois.

A somewhat lesser but real threat extends southwestward all the way down to Texas.  

We know we'll see severe storms and tornadoes in the Upper Midwest today, but we don't 100 percent know exactly how they'll evolve.

If supercells manage to form and maintain themselves ahead of the main line of storms later today, then we end up with the risk of strong, long-lasting tornadoes plowing through Iowa, southeastern Minnesota and Wisconsin. 

That scenario is a maybe/maybe not. But if these dangerous supercells erupt, they'll go from nothingburgers to extremely dangerous monsters in minutes. The National Weather Service office in the Minneapolis area is not mincing words in their forecast discussion:

"The takeaway from today's severe storm potential is to remain vigilant of the potential for storms to go up quickly. This may mean checking your phone more often or keeping an eye to the sky, but don't let your guard down in this environment."

 If, instead, the main line of storms exerts itself more, there might not necessarily be those supercells out ahead of the storm  This second scenario is still bad news, as there will be zones of destructive straight line winds and quite a few embedded tornadoes in this mess.

The most likely outcome  today is a combination of what I described above. The main question will be how many supercells form ahead of the main blast of storms. 

TUESDAY'S STORM ADVANCE

Tuesday's severe storm risk area is in yellow, with the
orange area at a somewhat higher risk. Note how the
yellow risk area extends into parts of Vermont, 

By Tuesday, the main threat from this dynamic storm heads east. The storm center itself will race up into central Quebec, but its powerful cold front will press east into the Great Lakes. 

Tuesday's threat area runs from southern Quebec and Ontario, then southwestward through northwest New England, the eastern Great Lakes, northern Ohio Valley then all the way down to central Texas. 

The greatest threat looks go from central Ohio, through northwest Pennsylvania and on into western and central New York.  

While there might be a couple tornadoes in this area, the main threat is damaging winds and large, destructive hail.

As noted, the severe threat extend into Quebec and northwest New England, so that puts Vermont in play. Details next:

VERMONT THREAT

This daffodil looks completely defeated and possibly 
dead after Sunday's snow in St. Albans, but....

Before we get into the severe storm threat, a final word or two on Sunday's snow.

A couple places got an impressive amount of snow. A high elevation spot in Greensboro reported .1 inches of snow. Brownington reported 3.5 inches.  

Here in St. Albans, it was striking how snowy and miserable it was in the early afternoon.

 By evening, it was a downright pleasant spring evening, with sunshine and relatively mild air. Go figure.

Today, by the way, will be gorgeous, with sunshine and temperatures in the 60s to near 70. Enjoy!

Now onto our next threat. 

But same daffodil three hours after above photo was taken
shows a nice recovery. This daffodil, and the rest of
them in the gardens, might have to endure some
severe thunderstorms Tuesday evening in northwest Vermont.

South winds ahead of that approaching cold front will throw a squirt of warm, somewhat humid air into Vermont. 

 Most of the day will actually be nice with highs reaching well into the 70s, with maybe an 80 degree reading or two in a couple of Vermont's more "tropical" towns. 

Dew points - a measure of how humid it will get - should reach the mid 50s to around 60. That's kinda humid for this time of year but not oppressive. 

Thunderstorms thrive on humid air, so the more muggy the air is, the more fuel for these storms. 

So the outlook for the thunderstorms in the humidity category is so-so.  

However, there will be strong winds aloft. Storms that do form can grab that high altitude air and shove it down to the surface, where we are. That's why there's the risk of severe storms.  A few of these could have wind gusts to 60 mph or even a little more. 

The heat from sunshine created instability, which is part of the reason why the thunderstorms are likely to be so strong over New York, since they'll hit there in the afternoon.

Timing is such that the storms look like they'll come in very late in the afternoon and evening. For instance, current forecasts have the best chance for thunderstorms in Burlington between 6 and 8 p.m. Tuesday,

By the time they reach Vermont, the storms will be beginning to diminish. At this point, it looks like a few storms still might have enough oomph to be severe generally in an area north and west of a line running from roughly Rutland to Montpelier to east of Newport. 

As the storms head toward southeastern Vermont later in the evening they'll diminish to nothing scary. 

Note that not everyone will get a severe storm. Northwest Vermont is in a level two of a five point risk scale, five being the hair-on-fire top scary alert. Our level two "slight risk" means scattered severe storms are possible, but they'll tend to be relatively short-lived and not terribly widespread.

So, just keep your eye to the sky Tuesday evening if you're in northwest Vermont and head inside if you receive a severe thunderstorm warning or see ominous skies to the west and north. 

The cold front might also produce some fairly strong winds after the thunderstorms go by.  These winds won't be associated with any thunderstorms, but they could cause very isolated power outages in a  few spots.

Unlike the cold front we saw this past weekend, it won't get nearly cold enough for snow.  Instead, Wednesday looks bright, refreshingly cool and breezy.  

Vermont Thursday Snow Thump Set To Arrive; Sunday Storm To Focus On Southern Parts Of State?

A gray an ominous sky over St. Albans, Vermont this
morning as we await that quick thump of snow that
will come through midday. A little freezing drizzle
later today will be the literal icing on the cake.

UPDATE 9:30 a.m

Boy, that snow came into Vermont awfully fast, faster than I thought it would.

At 9 a.m. I could see a wall of snow just blotting out the Adirondacks from my viewing point in St. Albans, Vermont.

By 9:15 it was starting to snow, and by 9:25  a.m. it was coming down at a good clip.

Radar seems to show the band of snow might wax and wane as it comes through, but you'll see bursts of heavy snow and poor visibility on the roads.

Sometimes the snow will come down torrentially.   Traffic cams showed near white out conditions at 9:25 a.m. in places like Route 7 in Shaftesbury and Route 9 in Woodford, both in southern Vermont.

Those road conditions should deteriorate awfully fast in the next hour, if they haven't already. If you're on the roads, I'd get home now and wait it out. If it's not snowing where you are, it'll go from nothing to pretty heavy within 10 minutes. At least in some areas if not all.

Be prepared for a very snowy few hours, but it won't last long.

PREVIOUS DISCUSSION 

 Skies were growing dark and ominous in Vermont as that anticipated quick thump of snow rapidly approaches from the southwest. 

Looks like the snow was just creeping into far southwest Vermont at around 8 a.m. and it will rapidly advance northeastward through the morning. 

At least the snow will warm us up. It was another frigid one before dawn today. Burlington in the banana belt managed to stay just above zero with an overnight low of 1 degrees.

 Elsewhere, it was 8 below in Montpelier and as low as 13 below in Morrisville and Lake Eden. 

You can see how the push of snow will eventually warm us up by looking at Bennington. It was 5 above there at 5 a.m. and up to 22 at 7 a.m. 

The snow still looks like it'll come down pretty hard late this morning and early afternoon, but will be in and out of here in a flash - like four hours or so.  That's why accumulations will be limited to one to three inches, or maybe four in some of the mountains and in a few parts of southern Vermont. 

Forecasters also haven't budged from their expectation we'll see some spotty freezing drizzle this afternoon and evening once the band of snow races out of here.  Temperatures look like they'll hold steady or even keep rising slowly late this afternoon through about midnight. 

This mornings snowfall prediction map for today. Aside
from adding a tiny bit more snow than previously
expected in southern Vermont, the forecast is pretty
much the same as that issued yesterday. 

Your drive home this afternoon or evening still looks like it could be dicey 

Warmer towns could get a couple degrees above freezing this evening.  But the ground is frigid from those cold nights. 

Even if your thermometer ends up saying it's 34 degrees out, any drizzle you're also seeing will probably be freezing onto your driveway and sidewalk. 

Overnight, the storm's inevitable cold front comes in with its snow showers and local squalls. Accumulations won't amount to much, but will keep some roads tricky for Friday morning. 

We'll have the added fun of some lingering snow showers (especially mountains) and blowing snow as west winds will start gusting to 30 or even 40 mph in spot starting early Friday morning and lasting pretty much all day.  Gusts could even reach higher than that in spots across northern New York and near some of the eastern slopes of the Green Mountains. 

Temperatures will be seasonably cold Friday and Saturday with highs in the 20s, lows in the single numbers

 NEXT STORM

It still looks like it will snow pretty much statewide later Saturday night and Sunday, but it's increasingly looking like this will be a southern Vermont focus.

Through virtually all of December and January, southern Vermont has missed out on snowfalls. They've mostly focused on northern Vermont mountains.

Now, the script seems to have flipped as the weather pattern is a new one that features storms racing across the nation and going off the East Coast.  Those tend to favor southern Vermont. 

Last Friday night, southern Vermont got a decent snowfall while the north missed out. Today's event looks slightly more impressive in the south than in the north.  

The early look on this Sunday's storm suggests six or more inches of snow south of Route 4, with less than five inches north of Route 2.   Now, this could change. The storm could jog north and give everybody in Vermont a big dump.   But as of this morning, the betting is on the south. 

This new southern bias in the snow is a good thing really. The effects of last autumn's drought are still most noticeable in southern Vermont. All that snow melting in the spring will help recharge ground water for the spring and summer. 

Like all the other storms in this parade, the Saturday night/Sunday system looks like it will race past us, so it won't have time to dump incredible amounts of snow.  But these things add up if you keep getting them over and over again. 

Long range forecasts have fast storms coming near us every third day or so.  It's impossible to tell from this vantage point how those quick hitters will affect us here in Vermont, but forecasters will need to really remain on their toes, probably for at least most of this month. 

I also so far don't see any signs of a huge thaw, which is a departure from recent winters.  It has not been above 45 degrees in Burlington since December 31, and it doesn't look like it will get that warm for awhile yet. Whatever snow you have is going to mostly stick around, and you're also going to get more installments. 

Keep those shovels handy. 

 

Horribly Timed Snow Squalls Slamming Vermont Late Today

Heavy snow in downtown St. Albans, Vermont
this afternoon.

 An intense line of snow squalls lumbered through the Champlain Valley of Vermont late this afternoon, snarling traffic and causing crashes throughout the region.  

It's not entirely over for Vermont as of 5:45 p.m. The squalls have been showing a slow forward motion, and were entering central parts of the state. And southwestern Vermont as well. Expect trouble on the roads to spread east for the rest of the evening. 

Pretty much all roads were backed up in Chittenden County at rush hour.  A large wrecker trying to retrieve an excavator that went into a ditch along Interstate 89 between Burlington and Winooski before the start of the squalls is complicating things further. 

The late afternoon squalls intensified and expanded as they moved out of New York state into Vermont. They ran into a temperature contrast. It was in the 30s most of the day in northern New York, but it reached the 40s in Vermont. 

The intersection of Main and Lake streets in St. Albans,
Vermont late this afternoon. 

This helped destabilize the air, allowing the squalls and heavy snow showers to blossom.  There was even at least one lightning strike north of Burlington during all this. 

On radar and especially visible satellite, the snow squalls really looked like a line of severe summer thunderstorms. 

The evening squalls weren't even the only ones. Another line of snow squall swept across northern and central Vermont mid-morning. Those caused their own issues, including crashes and slide offs along Interstate 89 in and near Williston. That mucked up traffic too. 

Even as the snow squalls diminish in western Vermont, colder air is moving in. Roads that were just wet will probably freeze as temperatures plunge. 

Overnight, snow showers will become lighter and more scattered, but snow will continue to pile up in the high elevations

From Facebook: Traffic crashes and tie ups along Interstate
89 between Williston and Richmond after the first
batch of snow squalls blew through this morning. 

Total snow accumulation should be one to three inches in most valley locations with this. Up to six inches is likely in the mountains. 

Snow totals from the valleys might seem inflated, but they really aren't. The Burlington area had about an inch of snow from the morning squalls.

 That melted, then another couple inches arrived late this afternoon, so that counts as something like three inches. (Final totals aren't in yet).

It will be quite cold for this time of year Thursday, with highs for many of us in the 20s. We're still watching a potential winter storm for Friday night and Saturday. I'll have more on that in tomorrow morning's post.   

As for this evening, stay in if you can. If you must drive, slow down, and expect delays. Some of those delays might be pretty long. Grab a tankful of gas before you get too far in case you're stuck for a couple hours out there. 

Slick spots on the roads will last into Thursday morning, too, so be aware of that. 

Yes, You Can Get Lake Effect Snows Off Lake Champlain

North winds created a band of lake effect snow off 
Lake Champlain this morning. Cold north winds picked up
moisture off the lake, and by the time those winds got
to a spot near Burlington, the snow began to fall a 
little over the lake.....

 The Great Lakes are famous for their lake effect snowstorms. Especially this time of year.

Cold air crosses the still relatively warm lakes. That warm lake water produces a lot of steam, which rises into clouds. The clouds head toward shore. 

The air once the cloud hit shore has to start rising to match the terrain. The rising air releases all that moisture in the clouds as snow. 

As we saw in Buffalo, New York last Christmas, these lake effect snow bands, when they're persistent, get quite scary. 

Smaller lakes can produce lake effect snows, too, if the wind is coming from the correct direction. Which is what was going on over Lake Champlain this morning.

The wind was coming out of the north, which is the same orientation as the long, skinny Lake Champlain. That kept the airflow over the lake long enough to produce those clouds, and eventually some lake effect snow.  A west wind wouldn't have worked. Lake Champlain is only 12 miles wide at its widest point. That's not a big enough fetch to create lake effect snows. A north wind is necessary.

You also need a pretty good sized contrast between the lake and air temperature. We had that this morning. The lake water temperature was 43 degrees and the air was close to 20 degrees. 

When the snow off Lake Champlain comes ashore, you rarely get those huge several foot deep storms. Lake Champlain lake effect is measured in just tenths of inches of snow, or sometimes a couple inches if you're lucky, 

The snow band kept getting a little stronger as you'd expect
as the clouds moved further south on the lake
and snow was falling over the lake and on the
shore. This is a view toward Shelburne. 

Radar images this morning showed lake effect snow falling from near Shelburne down into western Addison County.  

The people under the most intense - and that's being super generous - could see up to an inch of snow before the lake effect band breaks up by sometime this afternoon. 

There have been cases in which Lake Champlain lake effect snow has been impressive. 

On November 27, 1996, an oddly intense snow band of of Lake Champlain produced local snowfall rates of up to 1 or 2 inches per hour, with a total of 13 inches piling up in Cornwall, in Addison County. 

If you're going to see lake effect off Lake Champlain, it's most likely to happen in late November and December, and sometimes into January.  Later in the winter, much of the lake freezes over. The ice prevents that lake moisture from rising into the air to help produce our Champlain lake effect.

Rare "Red Flag" Fire Warning In Parts Of Vermont Today

UPDATE: 4 p.m.

A firefighter battles a forest fire near Bristol, Vermont
during a dry April several years ago. A Red Flag 
Warning is in effect in parts of Vermont for
high fire danger today. 

So far, conditions have pretty much played as expected in Vermont. 

We have a high overcast, which I think has helped keep winds a little lighter than first anticipated. 

There's still more than enough wind to fan any flames that get going, but at least it's not cranking at 30 to 40 mph so far, which would be even worse. 

But the air is still really dry, and the danger of brush fires will continue into the evening. 

The Red Flag Warning for lowlands in western Vermont and the lower Connecticut Valley is still in effect.

So far, as of around 4 p.m. , I haven't heard of any bigger blazes, which is good,. 

Far northern Vermont has thicker clouds, and radar is making out look like there's some light showers. But the air is so dry that anything coming out of those clouds evaporates on the way down. 

Looking at some of the darker clouds near St. Albans, you can actually see a little rain start to come out of the clouds, but disappears a short distance below cloud level.

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Continued southwest winds are keeping the air dry, so don't count on any rain. 

It still looks like fire danger will continue into the weekend.

PREVIOUS DISCUSSION
 

A Red Flag warning for fire risk is up today for the Champlain and lower Connecticut River valleys of Vermont and the lowlands of southwestern Vermont today. 

Such a warning means brush, wild and forest fires can easily start and spread rapidly out of control.  A Red Flag warning is fairly rare in Vermont, but this is the time of year you're most likely to see one. 

A combination of low humidity, all that dead, dry vegetation from last year, strong winds and kind of warm temperatures are prompting the fire warning. 

Today is a great day to not have any open flames outdoors. 

Those of you who had plans to torch your brush and branch pile today can fahgettaboudit.  First of all, you need a burn permit to do such a thing.  I doubt any towns in the red flag warning zone are issuing any today. 

By the way, if you're across the pond in New York, there's a burn ban there until May 14. A Red Flag warning is also in effect in much of eastern New York today, and pretty much all of southern New England. 

Also, don't flick cigarette butts out your car window, as you'll start a grass fire on the side of the road which will inevitably spread into the woods. 

Don't park your car on dry grass or weeds, either. Heat from the bottom of the car can start a fire. 

You might not think this brush and grass and forest fires are a big deal, but think again. They can cause some real property damage. 

Brush fires in Massachusetts last weekend spread to at least two homes, destroying them. Three weeks ago, an illegal burn pile became a brush fire that destroyed one home, damaged two others, and injured firefighters in New Jersey near the New York border. 

Central Vermont and the Northeast Kingdom are not covered by the Red Flag warning. In mid and high elevations, there's still snow, so there won't be much chance for a fire to get going. But in the valleys in these areas, ,enough snow is gone so that you can still get brush, grass and low elevation forest forest.

The most likely time for fire starts in Vermont today would be between about noon and 6 p.m. That's when humidity will be lowest, probably around 25 percent. It's also when winds will be strongest. They'll be cranking at 10 to 20 mph, with gusts in the 30 to 40 mph range. 

If you look at the sky and the weather radar early this morning, you'd think there's really not danger. A few dark clouds hung over St; Albans, for example. And radar seemed to indicate light showers zipping through the region. 

But looks are deceiving.  The air is quite dry, and any raindrops trying to fall out of the sky will evaporate before hitting the ground. 

Even if a couple rain drops do land this morning, low humidity and strong winds will dry those away quickly. 

We'll have to watch out for fires through the rest of the week and into the weekend, too.

Tomorrow won't be as windy, but dry northwest breezes will keep the humidity low, and the wind will one gusty enough to spread fires. 

Somewhat higher humidity Thursday might help a little, but not solve the problem. Friday and possibly Saturday look quite dry, too.

There is a decent possibility of a fairly soaking rain Sunday night, which would help. 

If you're going to get a brush or forest fire in Vermont, April is the most likely month. The snow is gone, at least in most places. It hasn't really started greening up yet. Forests are still leafless, so strong April sun can get down to the ground and dry things out quickly. 

As I mentioned in a previous post, super dry high pressure systems from southern Canada often slide through New England this time of year, raising the risk of fires. 

This fire risk doesn't mean we're entering another drought. Beneath the dry vegetation, the ground is still nice and wet from a relatively soggy winter. 

If we keep seeing dry weather week after week, then we need to start worrying about drought. But we're not anywhere close to that yet. 

Even Today's Vermont Snow Forecast Is Tricky, Never Mind Rest Of The Month

The National Weather Service office in South Burlington
released this snowfall forecast map for later today.
Decent snows seem likely southwest of Vermont, but
the Green Mountain State looks like it will get a
dusting to two inches. We'll see how it plays out! 

As I've said in previous posts, it's especially hard to predict the weather this month. Even today's forecast is pretty tricky. 

Snow is moving toward Vermont this morning, but how much of it will actually get here? 

Current forecasts have most of Vermont barely squeezing out an inch or two, with even less than that north and east of Interstate 89. A few places in southwestern Vermont could squeeze out two inches of snow this evening. 

That said, this is a tiny bit more than previously forecast, and during periods of steadier snow this evening, even this little bit of snow will be enough to slicken up the roads. 

Be careful if you have to drive. At least the thin snow cover most of us will receive will brighten up the landscape a bit and give things a more holiday season feel. 

You'll see on radar that the snow coming in from the southwest will look like it will dump more than forecast. A good slug of snow wants to come in today but will run out of gas in route. Areas south and west of Albany, New York can expect three to six inches of snow out of this storm system. Same might be true in southwestern New England, like in parts of Connecticut. 

There's been so much frost in St. Albans, Vermont this 
week that it looks like there's a dusting of snow on the
ground. There isn't yet. That's just lots of frost.

But the moisture is encountering dry air as it gets here, so the initial snow will evaporate on the way down from the clouds. 

Then, as the system from the west comes closer, a new storm will form off the coast, stealing the moisture from that weaker system in New York. 

Dry air will flood back into Vermont on the north winds created by the coastal system. That'll shut off the snow pretty quickly tonight. 

The wild card is how much the dry air will evaporate the snow.  And how strong that push of snow is that's coming at us from the southwest.  

Interestingly, those predicted snowfall amounts southwest of Albany and in and around Connecticut have pretty drastically increased in the past few days.

Will the snow later today over-perform in Vermont? It's possible, but don't count on it. 

LATER WEEK

If meteorologists think today's forecast is tricky, they're really at a loss for a potential storm late in the week. There's still no consistency as to whether it will come close enough to give us a snowstorm, a mix, or pretty much nothing at all. 

We do know a storm will be crossing the nation, causing all kinds of weather problems on the way. We just don't know the path it will take once it gets near the East Coast. 

At least we have a good handle on what will happen between Monday and Thursday. It'll just be rather cold, and pretty quiet. 

 

Wintry, Windy Rest Of Sunday In Vermont, And There's Always Some Sort Of Storm Thanksgiving Week

The National Weather Service's seven day map of expected
precipitation shows something coming through the 
Northeast. We'll see what happens.

This is among the stormiest times of year in the United States. The increasingly strong rushes of cold air from Canada conflict with the lingering warmth of autumn in the south.  

Plus the Gulf of Mexico, Atlantic Ocean and the Great Lakes don't cool down in the autumn as fast as the air. So they're relatively warm.  

All this clashing helps encourage storms. There's almost always some sort of disruptive storm somewhere in the nation during Thanksgiving travel time.

True to form it does look like we here in Vermont will have to deal with some sort of precipitation event toward the end of the week. How much and what type of precipitation is still way open to question, but it's something to keep an eye on.

The good news is it looks like whatever comes out of the sky will wait until after Thanksgiving Day itself to do so.

Before we get there, we'll have to deal with a pretty real blast of winter today and tonight.  Some of the last vestiges of that huge band of lake effect snow made it into Vermont early this morning, so many of us saw a dusting of new snow.

Meanwhile, a piece of the famous polar vortex is being tugged down briefly right on top of us today and tonight.

As a reminder, the Polar Vortex is a normal big circulation of very cold air that always sets up shop somewhere in the Arctic during the winter. It drifts around, and sometimes it gets elongated so that it extends further south, or pieces of it break off. Whoever is under the elongation or the broken piece gets to enjoy a sharp cold snap.

Today's our lucky day. 

The super cold air aloft will do three things today that most of us won't welcome. The just sort of cold air near the surface and really, really frigid air high up will increase instability. So you'll see an increase in snow showers, and some of them could be very briefly heavy.

Accumulations won't amount of much, but these could create visibility problems on the roads, along with icy patches

The second thing is the wind coming across the relatively warm water of Lake Champlain might enhance the snow showers on parts of the Vermont side of the lake at least to the summits of the Green Mountains.

This won't be anything like the six feet of snow from the recent Lake Erie snow blitz, but some spots could see an extra inch or two of snow in some areas.

The third thing the cold air aloft is giving us is fairly strong, gusty winds. The same instability that will cause those snow showers will grab high speed air from aloft and bring it to the surface.  I wouldn't be surprised if a couple places have gusts to 40 mph. Many of us will reach at least 30 mph.

This will bring wind chills down to as low as 10 degrees.

Speaking of 10 degrees, some places in Vermont will get that cold tonight and early tomorrow. Not wind chill, actual temperatures. 

The super cold air aloft will quickly depart and go back up where it belongs over Canada, so the weather will turn normal between now and Thanksgiving - highs within a few degrees of 40, lows in the 20s.

Then there's the storm this weekend.  Chances of some sort of precipitation in Vermont Friday and/or Saturday seem to be going up and up. 

We really don't know how much precipitation we'll get and whether it will be snow, rain, ice, slush or all of the above.  A lot of it will depend on whether a coastal storm gets going in this mess, how strong it will get, and whether the coastal storm, if it forms, goes a bit inland or offshore. 

Stay tuned! 

 

Cool Satellite Shot: A "Dry Slot" Moving Into the Region

Visible satellite image from late this morning shows a
very well defined "dry slot" a narrow band of clear air
on the east side of a storm over the Great Lakes. Dry slots
are very common in mature storm systems. 

 The visible satellite image of the northeastern United States and southeastern Canada was fun and interesting late this morning, at least for a weather geek. 

It shows what is known as a "dry slot" extending up through the eastern United States. You can see it in the satellite image on this post. Click on the image to make it bigger and easier to see. 

Dry slots are very common with mature storm systems.  A relatively narrow band of dry, sinking air gets entrained into the southern and eastern parts of a storm.

Sometimes, it stays cloudy in a dry slot, but precipitation largely shuts down. Other times, the sky gets clear in a relatively narrow band.  That's what's happening here.

A parent storm is over the Great Lakes, bringing in cold, cloudy air to that region, with rain and snow showers. The storm's cold front has pushed on into eastern New England. A classic dry slot has formed, and as of late morning, extended from the Carolinas, through central Virginia, Maryland, New Jersey, eastern Pennsylvania and central New York. 

On either side of this narrow dry slot, it's cloudy and cool. Under the dry slot, skies are spectacularly clear. It's still not particularly warm, but it is pleasant under it. 

The dry slot was edging closer to Vermont late this morning, so it gives us the prospect of sun breaking out this afternoon. Which will be a terrific alternative to the gloomy conditions we had this morning.  The dry slot's clear skies should linger tonight.

That means there's a good risk of frost in the Champlain Valley, where the growing season is technically still going. The National Weather Service has issued a frost advisory for this area tonight. 

 Temperatures in much of Vermont will be near or below freezing tonight.  The growing season is considered over in these areas, so there's no frost or freeze alerts outside the Champlain Valley. 

This is the second classic dry slot we experienced in a week. On Friday, after an early morning of heavy rain, skies abruptly became clear and pleasantly mild in much of Vermont last Friday afternoon.

UPDATE: 11:15 a.m

Storms earlier over far northwestern Vermont and southern Quebec were just a teases, and now the main show is beginning.

Storms like this one developed yesterday in the hot humid air
in northwestern Vermont but couldn't sustain themselves.
 A trough of low pressure and a cold front will ensure that
storms, some severe will be prevalent this afternoon.

Storms have started to strengthen over the Adirondacks as they move northeastward toward northwestern Vermont.

Other storms are just about to take off.  NOAA's Storm Prediction Center said just a short while ago they expect to issue a severe thunderstorm watch for parts of eastern New York and New England within the next hour. The watch will almost surely include parts of or all of Vermont.

Remember, a severe thunderstorm watch means conditions are favorable for severe storms.  A severe thunderstorm warning means a dangerous storm in imminent. I will be out reporting and documenting  the storms today, so for brief updates, see my Twitter feed, @mattalltradesb

UPDATE 9:45 a.m. 

Storms already just starting to get going NW tip of Vermont. Expecting them to develop further south soon.

They'll develop rapidly, I think, and move swiftly across northern Vermont.  Forecast as set by the National Weather Service and described below still looks good.

 

PREVIOUS DISCUSSION, 9:15 a.m.

Before we get into today's severe weather threat, can we talk about last night? The overnight low of 80 degrees in Burlington would tie the record for the warmest "low" for any date in history.  

The record was first set in 2018.  I doubt this record will hold as thunderstorms and a cold front will ver likely drop temperatures below 80 degrees by midnight tonight. Still, last night was impressive, and not in a good way.  

You can tell by the oppressive airmass over us that we can get storms easily. We saw that yesterday, when some pop up storms prompted a couple of severe storm warnings over northwest Vermont.  The storms couldn't really last, since there wasn't a trigger to keep them going, but it was a demonstration of how easily a storm could form in an instant.

Today, the trigger IS there for storms that will last and streak across Vermont. 

Given all the heat and humidity, it won't take much for today's thunderstorms to get going.  They'll begin earlier than we're used to in hot, oppressive weather. 

Traditionally, we wait until at least early to mid afternoon for storms to really get going during summer storm outbreaks in Vermont.

However, the first disturbance, a "pre-frontal trough" should reach the Champlain Valley by around 11 a.m. Usually, when these little disturbances reach the western Vermont border that early in the day, then places west of the Green Mountains miss out on the storms. The storms focus on eastern Vermont.

Not today. The atmosphere is so primed that storms should easily begin to pop up in eastern New York as early as 10 a.m. today.  A broken line of strong storms could well be entering the Champlain Valley by 11 a.m. 

(One model has storms getting going by 9 a.m., about the time I'm writing this, and I just don't see it. There were a couple isolated storms in southern Quebec, but I think it'll be another hour at least before things really get going).

Not everyone will see a storm, which is the usual case.  NOAA's Storm Prediction Center continues to go with a slight risk of severe weather over Vermont today, which means there will be scattered instances of storm damage, but the majority of us should be OK.  Of course, you never know exactly who gets the severe storm until they form and move over you, so it's a crap shoot. 

Some of the storms that will be around will  become strong to severe pretty quickly.  This initial broken line of storms will probably intensify somewhat further as they zip across Vermont early this afternoon and into New Hampshire by mid-afternoon. 

Most of New England, including all of Vermont, remains
under a slight risk of severe storms today. That means
there will likely be at least scattered instances of
storm damage. 

Behind that first line, the atmosphere looks like it will be unstable enough to allow more storms, some possible severe, to develop early this afternoon in New York and cross Vermont in the mid to late afternoon, with the late afternoon storms focused on eastern and southern parts of the state. 

As is always the case, not everyone will see a severe storm. Just a few places will get nailed. But those who do get nailed could see some real damage. As previously forecast, winds aloft are pretty strong for this time of year, which can really help with the strong downburst winds with some storms. Some of these gust could be strong than the usual 60 mph whiffs we get during "traditional" strong storms. 

 A few places could also see some large hail. 

The threat of tornadoes is very, very low but not zero. Winds do change direction with height somewhat, but the airflow isn't ideal for tornadoes. However, it's within the realm of possibility that a renegade storm ahead of the main line of clusters of storms today could produce a brief spin up. 

Today really looks like a hit and miss situation. As noted, a few places will get absolutely nailed. A fair number of us will have sub-severe storms, meaning dangerous lightning, gusty winds, torrential downpours, that kind of thing. Some of us will also skate by with pretty much nothing at all.

Since storms will be developing rapidly and zipping right along once they do form, it's best to stay close to home or office today. No hiking, no going out for a quick spin with the boat on the lake.  I'd even stay fairly close to home when it's time to go walk the dog. 

If you do get a severe thunderstorm warning, just get yourself in a sturdy building, stay away from the windows as best you can and you should be fine. Also remember, you might see a storm coming and not be under a severe storm warning. But that approaching storm could turn severe by the time it reaches you, so it's best to consider that as well.

The good news about these storms getting going so early in the day is that they'll be over fairly early, too.  We might see a few renegade, tardy storms at the first part of this evening, but they'll probably be few and far between. 

A cold front is helping to cause this. And with the dynamic atmosphere, you'd expect it to be nice and refreshing and cool starting tomorrow. Nope!!

It'll be slightly less humid and slightly cooler, but temperatures will still top out in the upper 80s, with a few spot 90 degree temperatures Friday and Saturday. 

We'll have to watch another storm Sunday, which could cause more severe weather.  After that disturbance, it looks like we do get into fresher air early next week.