Transition Out Of Heat Brings Vermont/Northeast Severe Risk Today

This image from the National Weather Service in South Burlington
shows much of Vermont and New York under a slight risk
of severe storms today (areas in yellow).

Today will be the last day of the unseasonable, record breaking  heat and humid that has enveloped northern New England and southern Quebec.

The price for this transition will be the risk of severe thunderstorms.

NOAA's Storm Prediction Center has a large chunk of the interior Northeast away from the coast under a slight risk of severe weather. This includes all of Vermont except basically the Connecticut River Valley, which is under a marginal risk.  

A slight risk for severe storms is level two out of five on the alert scale for dangerous weather. A slight risk means that scattered severe storms are possible, but they would generally be not terribly long lived. An isolated intense storm could develop, too.

I'm thinking it's possible part of the slight risk zone could go up a step to number three on the alert level, which is "enhanced" risk.  That would mean a somewhat more widespread outbreak.  I would emphasize this idea of an upgrade to level three enhanced is JUST speculation on my part and NOT part an official National Weather Service forecast.

One thing that would help big storms get going is if sunshine  between now and early this afternoon helps destabilize the atmosphere. Satellite images early this morning showed a fair number of breaks in the clouds over Vermont and upstream in New York.

The main risks with today's severe weather threat in Vermont and much of the rest of the Northeastsare strong straight line winds and downbursts.  These could be enough to cause local damage to trees, power lines and maybe even structures.  Most of us won't see anything that bad, but a lot of us will hear thunder, see lightning and probably get a gusty downpour or at least a shower our of it.

There is even a remote chance of a brief spinup tornado once again from around Montreal south through the Champlain Valley and on down the eastern slopes of the Appalachians all the way to North Carolina.

There is some spin - changing wind direction with height - that could create some rotating thunderstorms. Remember, though: Just because a thunderstorm is spinning doesn't always mean it will produce a tornado. It's something to watch today, just in case.  Don't count on a tornado, though. It's a very, very low chance.

Another thing to consider today is the risk of so-called training thunderstorms. That's when a line of thunderstorms, like boxcars on a train track, go over the same spot over and over again. These storms can cause torrential rains and flash flooding.

The risk of this happening today is fairly low, because it's been so dry lately.  It would take a helluva lot of rain to set off a flash flood. It's still one more thing to keep an eye on, though.

There will probably be several rounds of showers and storms this afternoon and tonight affecting different parts of the state at different times.  Storms will probably start to ramp up in New York State by early afternoon and spread eastward into Vermont.

Everybody will get rain, but there will be winners and losers. Some places will get a nice, needed soaking and a few places will get a pathetic light showering. It's a crap shoot that's impossible to predict in advance. I'm rooting for a nice drenching here in dusty St. Albans, Vermont.

All this will leave us with cooler and drier weather on Saturday. A second cold front will pass through Saturday evening. It will turn quite chilly for the opening days of June, as has been advertised for days now.

A few places might not get past 60 degrees for highs Sunday and Monday, which is a far cry from the 90s earlier this week.  Also, if there are clear skies on any of these nights, a few colder spots would be at a risk of frost.  Most of us will be fine, though.

Weekend Storm Still Looking Dangerous For Vermont, Many Other Parts Of Nation

Will northern Vermont get a nasty, but manageable amount of ice like
this over the upcoming weekend or will it be worse?
Nobody is certain yet, stay tuned! 

It looks like I'll want to do daily updates on the approaching potentially dangerous storm this weekend here in Vermont. At least until it hits.

The expected vast, serious storm continues to put Vermont at risk for flooding and potentially damaging ice.

The storm is a forecasting nightmare and will continue to be even when it is in progress Saturday and Sunday, so expect surprises.  Not all of the surprises will be pleasant, for sure.  

At this point, if forecasts go amazingly close to accurate, some flooding is a good possibility across a good chunk of Vermont, given the rather heavy rain and snow melt that will come with the storm.

The highest potential for damaging freezing rain and ice accumulations are in the northern and maybe central Champlain Valley and parts of the Northeast Kingdom. Sections of northern New York and southern Quebec are also under the gun with this scenario.

The first piece of this storm will rocket from around Kansas to the Great Lakes today and tonight, driving a warm front through Vermont.

After today's chilly weather, you'll notice temperatures going up overnight tonight. In the Champlain Valley, you'll really notice the wind pick up, with gusts to at least 45 mph in spots later tonight and tomorrow morning.

Meanwhile the main storm will start to gather around Texas. That's why there's a severe weather outbreak scheduled for Friday and Saturday in the Deep South.

The storm is transporting huge amounts of moisture and heat northward in the eastern third of the nation, which will produce that heavy rain in the Tennessee and Ohio valleys, and the record warmth along the East Coast.

A band of freezing rain and sleet will travel along the northern and western periphery of the storm.  That's where Vermont's troubles come into play.

Cold high pressure is stll expected to establish itself in Ontario and Quebec. That would push a cold front down into northern New England, including northern Vermont.

What comes from the sky, then, during the storm will depend upon where this weather front gets stuck, or wavers back and forth. If forecasters are off on its position by as little as 10 or 20 miles, then the weather forecast for the storm will be wrong.

The reality check is, forecasts are almost alway off by a dozen or two doze  miles with the location and speed of a cold or warm front no matter what the situation.  Usually this margin of error has little effect on weather forecasts and the predictions end up being accurate.

I doubt it this time. That's because, first of all, the temperature contrast across the front will be tremendous.  I can see a scenario in which its 30 degrees in St. Albans and 60 degrees in Rutland during parts of the storm.

On top of that, this is shallow, low level cold air coming in from the north. Temperatures aloft will remain very balmy.  It's possible in northern Vermont we could get temperatures in the upper 40s on the summits of the Green Mountains while freezing rain coats trees and power lines in the valleys.

If current forecasts are to be believed, the cold air would begin bleeding into the Champlain Valley, some spots in the Northeast Kingdom and northern New York Saturday afternoon or evening.

We don't know how far south the front will get, and whether it will lift back across the International Border during the height of the storm.

If the front stays draped across southern or central Vermont, the northern Champlain Valley and other northern locations could easily see the worst ice storm since the epic one in 1998.  Although, looking at the bright side, there seems to be no way this one would be as bad as 1998.

I have seen in some of these situations that the cold air from Quebec can bleed south along valley floors as far south as Rutland, so we'll have to keep an eye on that.

On the other hand, if southerly winds win out, the temperature would stay or go back above freezing Saturday night all the way to the Canadian border. That would be nice in that we'll escape the worst of the damaging ice.

By the same token, that warm air north would put all of Vermont in play for the risk of flooding. Heavy rain mixed with temperatures in the 50s to around 60 melts snow pretty quickly too.

The heaviest rain or ice or even possibly sleet or snow in the far north would come down Saturday night and early Sunday morning. It would taper off pretty quickly on Sunday afternoon as the storm heads away from us.

Stay tuned on this one.  It's certainly shaping up to be the first really nasty storm of 2020.

Heads Up: Dangerous Storm Eastern U.S. This Weekend. Vermont Effects Included

Precipitation forecast map for th next seven days. Most of the
precipitation you see is with the forecast big stom this weekend.
Purple shades, as in over Vermont, depict about 1.5 inches of
rain or melted snow and ice. That huge area of bright
red is two to seven inches of rain, so you
see a big area that's under a flood risk. 

I usually don't like to hype storms too far in advance. As most of us know, computer models more than a few days out can be unreliable.

This time, though, I'm going into hype mode, at least to an extent. The computer models have been consistent in saying some rough weather is due in the eastern half of the nation Friday through Sunday.

It's rare to see the Storm Prediction Center highlighting a risk for tornadoes and severe storms five or six days in advance.

But that's what they're saying about a zone from eastern Texas and across the Gulf Coast states Friday and Saturday with this system.

The devil is always in the details, so we won't know how extensive this severe outbreak will actually turn out to be. But there is the risk, at least of some pretty significant tornadoes and high winds across the South Friday and Saturday.

Likewise, this storm is going to have a LOT of moisture to work with.  Parts of the South, and Tennesee and Ohio valleys have been quite wet of late, and early predictions are already touting two to six inches of rain with this system in that region.  Some flooding is already ongoing, so it will only get worse this weekend. 

This storm will likely get some of its power from a very strong Bermuda-high like ridge of high pressure off the East Coast.  That will probably create some record high temperatures in the coming days along the Eastern Seaboard.

The arrangement of that ridge of high pressure will bring quite a lot of moisture inland off the Atlantic and the Gulf of Mexico.

Meanwhile, a strong dip in the jet stream, and a strong jet stream aloft, will provide plenty of energy and instability for heavy rain, thunderstorms and possible southern tornadoes. And winter cold air from the west will just add a clash of air masses to wring the heavy precipitation as the system heads northeastward.

You'll very likely hear about this storm in the news in the upcoming days and through the weekend. Unfortunately, it could easily prove deadly and destructive in the South.

VERMONT IMPACTS

The storm will inevitably head northeastward into New England. For us here in Vermont, something nasty looks like a near certainty over the weekend, but what form that nastiness would take is still anybody's guess at this point.

We know there's a good potential for precipitation to be heavy.  Perhaps one to two inches of liquid equivalent, which is a good thumping for mid-winter, which tends to be drier.

But will it rain? Snow? Freezing rain? Locusts?  All of the above?  For now, I'm going with all of the above, except for the locusts. I'm pretty sure we won't get locusts.

We won't know exactly what will happen until nearly the last minute. But I'd start planning for difficult travel on Sunday.

We could easily have another messy ice deal like we did back on December 30, though the precipitation this time looks like it might be heavier.

It all depends upon when cold air from the northwest plays out.

Here's how the National Weather Service in South Burlington thinks it'll play out.  Remember, results may vary, and forecasts will change. Stay tuned for updates.

We'll start out with a brief shot of Arctic air Wednesday afternoon through Thursday. Thursday will be the first colder than normal day around Vermont since December 21.  Lows will be near zero, with highs in the teens to near 20.

Yeah, that's cold, but no great shakes for a Vermont January day.

Then the fun starts. Temperatures will start rising Thursday night as winds pick up from the south.  A piece of the storm will draw a warm front through, causing some light mixed precipitation going over to some light rain Friday.

The real problem Thursday night and Friday will be strong winds, created by the contrast between that vigorous ridge off the East Coast and storminess to the west.

It'll continue to warm up Friday into Saturday, but how warm it gets depends upon when a cold front arrives. Could be record warm, could be just kinda warm. We'll see.

Here's where it gets really complicated. Chilly high pressure will come across the northern Great Lakes and into Ontario and southern Quebec. That would feed cold air in the lower levels of the atmosphere towards us here in Vermont.

Meanwhile, warm, wet air will glide northward up above that chilly air.

How cold will it get and how far south will the chilly air make it?  If the answer is very little and it stays warm, we'd get a lot of rain and we'd have a flooding risk.

If mostly low level cold air comes in but it stays warm aloft, that sets us up for a bunch of freezing rain and sleet.

If the cold air blasts in, we get a lot of snow.

Take your pick, because nobody is yet sure which scenario would play out, and where in Vermont different types of precipitation sets up.

Here's a worst case scenario for you, though. In their forecast discussion, the National Weather Service in South Burlington compares the overall weather setup this weekend to March 6-7, 2011.

On that occasion, we got a bunch of rain and melting snow, which led to some flooding. Then, the colder air came in, changing rain to snow, especially across the north. There was a LOT of snow with that March, 2011 storm. 

Burlington got 25.8 inches of snow, which was up until that time the greatest March snowstorm on record. (Later usurped by the Pi Day Blizzard of March 14, 2017).

Most of northern Vermont got around two feet of snow in that 2011 event.

I'm not saying history will repeat itself this weekend. I'm guessing it won't. But as I said at the start, this is a head's up.

Two Very Different Style Windstorms To Affect Vermont, California

Widespread rainfall of near two inches is expected with the
upcoming windy storm Thursday into Friday.

This is essentially an update to yesterday's post, with more details about a pretty stiff storm about to sock us here in Vermont, and a nearly unprecedented wind event (and possibly fire event coming to southern California today.

Let's start locally.  It's already been breezy in parts of Vermont, especially the Champlain Valley, as I drove through a blizzard of falling leaves amid 30 mph wind gusts.

That's just a foretaste of what's to come.  Yep, we are going to get a lot of rain and wind.  There's a risk of both flooding and damaging winds Thursday night and Friday in and around Vermont.

I suppose way out ahead of the main storm there could be a couple light showers this afternoon, but they're nothing to worry about. 

The main show arrives tomorrow. At first, it'll just be showers, but a steady rain will move in during the afternoon as winds increase.

It's tricky to predict how strong winds will get while it's raining.  There will be strong winds aloft, but  rainfall can sometimes prevent those winds from mixing down to the surface.

There will be locally strong winds.  Meteorologists at the National Weather Service in South Burlington think channeling effects in the Champlain Valley could bring gusts to 45 mph there.

Worse, the southeast flow could bring strong downslope winds to the western slopes of the Green Mountains. There's definitely a risk of gusts in the 60 to 70 mph range, with maybe a couple locally higher gusts along the western slopes of the Green Mountains Thursday night.

That will be Round One of the wind. More on Round Two at the moment.

Between the wind and the rain, it's not going to be a great night for trick or treating. Overnight, this noisy storm will likely produce a lot of rain.  Most of the state should get one to two inches, with locally three inches possible.

We've had a lot of rain lately, so the soils are saturated. This amount of rain is probably enough to cause some flooding. It won't be an Irene-style epic flood, but even minor flooding is something to pay attention to.  People always tend to try to drive across flooded roads and that's such a bad idea.  This should be obvious, but whatever.

It seems the rivers most at risk of some flooding are the Mad and Winooski and Other Creek in Vermont and Ausable in New York.  But any water way could flood, and small streams could wash out dirt roads.

Newly fallen leaves can form little dams in streams. When these dams eventually break, you get rushes of water that can take out culverts or wreck gravel roads.

In urban areas, newly fallen leaves can can clog storm drains, too.  Needless to say, a flood watch is up pretty much region wide.

Friday morning, the storm's sharp cold front will whip through, which will shut off the heavy rain. (Lighter showers will continue here and there.)

This cold front opens the door for more strong winds, this time from the west.  Gusts in favored areas could reach 55 mph. Most of us will gust over 40 mph Friday.

Overall, there's already a high wind watch up in northwestern New York and those wind watches, warnings and advisories will almost certainly spread across most of Vermont.

Obviously, the large upcoming storm won't just affect Vermont.  The entire Northeast is due for a big blast of wind, rain and power outages with this storm. 

Not everybody will lose electricity, but there will be outages.  Make sure your devices are fully charged by Thursday evening, just in case.

CALIFORNIA WIND/FIRES

It seems like we've been talking about the California wildfires for weeks now, though it's only been days.

It also seems like every time we say this will be the worst day, an even worse day comes along. That's today in southern California.

Meteorologists are predicting one of the strongest Santa Ana winds on record in southern California. This will be combined with a relative humidity of well under 10 percent.  Santa Ana winds and fire weather occur every autumn in southern California, but not like this.

Every time there's a real fire risk, something called a red flag warning is issued.  This happens a lot in southern California in the autumn, so the National Weather Service in Los Angeles worried that people would just dismiss it as just another background noise weather alert.

To shake people out of their complacency, they're calling this one an Extreme Red Flag Warning. "Conditions are as dangerous for fire growth and behavior as we have seen in recent memory," the NWS warned. 

Unlike most Santa Ana wind events, the weather won't be particularly hot this time. Normally, the air rushing down the hills in Santa Ana winds compresses, which heats it up. The air mass triggering the winds is so cold that this warming won't be very pronounced.

Unfortunately, that doens't matter.  Between the winds gusting to 80 mph on the ridgelines and in some canyons and 60 to 70 mph elsewhere; and the relative humidity running in the single digits, you can imaging how fast a fire would spread.  I don't think any human could keep up with it.

So, millions of people in southern California are on edge, wondering if they will be the ones who have to flee in a flash because of a fire.

The winds are so strong this time that even outside fire zones, the National Weather Service is saying people should stay out of forested areas and away from trees.  They could topple easily in such strong winds.

I guess we here in Vermont should count ourselves lucky that we're only going to get lowland flooding, a few toppled trees and power failures.

Barry's Legacy Will Probably Be Another Epic Flood

Severe flooding in Louisiana in 2016 caused by a stalled weather system.
What is to become Tropical Storm Barry will also be moving
quite slowly, so it could unleash similar serious flooding
UPDPhoto by Bill Feig/The Advocate

UPDATE 1 p.m. 

s expected, that storminess in the Gulf of Mexico was upgraded to Tropical Storm Barry late this morning.

The National Hurricane Center says it now has a better defined circulation and has sustained winds as high as 40 mph, so Barry now qualifies as a tropical storm.

The system is still a disorganized mess though, with upper level winds and intrusions of dry air messing Barry up.

Still,  Barry is still expected to intensify, and might, MAYBE achieve hurricane status before landfall over the weekend.

That doesn't matter all that much, though, as all the rain with Barry is the real problem. Flooding is going to happen somewhere along the Gulf Coast. Probably Louisiana.

That said, the exact track of the storm is super uncertain. It could hit land anywhere between Mississippi and the upper Texas coast. Whereve it hits, the heaviest rain will come over and just east of where it comes ashore.

PREVIOUS DISCUSSION

The storm system that everybody's been watching in the Gulf of Mexico, the one destined to become Tropical Storm Barry, was still trying to get its act together this morning.

No matter what happens with this thing, though, it's almost guaranteed to bring somebody a terrible, epic flood. Once again, we'll have big time flooding in the news.

Wannabe Barry is still a wannabe because no real noticeable center of circulation had developed as of early this Thursday morning. Where that center forms will be key in where Barry goes. There's still questions on where precisely it will make landfall and at what strength it will do so.

Although everybody, including me, wants to know those particulars, in essence, it doesn't matter. The serious flooding from this is already almost locked in stone. It appears Louisiana or Texas and on up into probably Arkansas and Mississippi are at the greatest risk.

Yesterday, I mentioned how a storm surge from wannabe Barry pushing upstream along the already high Mississippi River could overtop levees. That's still a definite threat, but even if that doesn't happen, the flooding will be widespread and very dangerous.

One of the big reasons for that is wannabe Barry is in no hurry to get anywhere. Steering currents in the atmosphere are weak, so it won't move much. Which means the downpours will linger over a particular area for a long time, creating spectacular rainfall totals.

Current predicts are for at least a foot of rain in the areas especially targeted by Barry, and the latest best guesses are that would be Louisiana, possibly including the already flood-soaked New Orleans. Some areas could get up to 20 inches of rain.

This slow moving set of downpours sets up a potential disaster that has similarities to the stalled Hurricane Harvey in Texas back in 2017, or that no-name stalled August, 2016 storm that dumped up to 30 inches of rain on Louisiana, causing another epic flood.

Needless to say, flood watches are up along much of the northern Gulf Coast between the Florida Panhandle and central Louisiana.  I suspect those flood watches will be extended westward toward Texas, especially if it looks like wannabe Barry goes further west, too.

It's interesting that there is a hurricane watch up for coastal Louisiana even though wannabe Barry isn't even a tropical depression yet. At least as of this writing.  It's certainly possible this storm could reach hurricane strength by early Saturday morning, especially if it stays off the coast over the warm Gulf waters long enough.

This would add some wind damage to the mix from wannabe Barry. And be dangerous for very low lying coastal areas. Low, swampy areas south and east of New Orleans were already being evacuated this morning because of the risk.

Regardless of whether this turns into a hurricane or not, the inland flooding will be the real impact.  This year has been another in a series with devastating floods in the United States. And it's about to get worse, unfortunately.

Here's some video clips of the flooding in New Orleans yesterday that was probably a prelude to the upcoming, bigger flooding disaster:

Will "Wannabe Barry" Turn Into Another New Orleans Hurricane Calamity?

Serious flash flooding in New Orleans this morning. Is this a
prelude to an even bigger calamity from wannabe Barry?

New Orleans was badly flooded today as a storm that wants to become Tropical Storm Barry gathers steam in the northeastern Gulf of Mexico.

This morning's flash flood emergency in New Orleans was created by intense thunderstorms on the outer edges of that mishmash of Gulf thunderstorms that might become Barry. Up to six inches of rain fell in just three hours this morning.

Many parts of New Orleans, including the French Quarter were under water this morning. If the worst case scenarios with wannabe Barry play out, this morning's destructive flooding will look like child's play. Things have the potential to get very difficult in the Big Easy.

You might remember my post a couple days ago that mentioned a cluster of thunderstorms that had its origins in Missouri and Tennessee was drifting down to the Gulf of Mexico and had the potential for grow into a tropical storm.

That potential seems like it is being realized. The National Hurricane Center says wannabe Barry will almost certainly grow into Tropical Storm Barry by Thursday and could easily increase further into a hurricane by the weekend.

The future path and strength of wannabe Barry is wicked uncertain, but early indications are it will move west over the northern Gulf of Mexico, then turn north and make landfall somewhere west of New Orleans.

If that happens, New Orleans would get the worst of the storm surge, which is water pushed ashore by a storm.

That's bad enough for low lying New Orleans. However, under normal circumstances, a storm surge being pushed northward up the Mississippi River by the city wouldn't be that big of a deal, as a levee system would protect the area.

Hurricanes in the Gulf of Mexico usually hit later in the year, when the Mississippi River is typically pretty low. The levee system around New Orleans protects the city unless the water gets more than 20 feet deep.

So if a storm surge increases the water level in the river from, say, five feet to 10 feet, the city and its levees can handle it.

Here's the problem: Wannabe Barry is gettting going early in the season, so the Mississippi River is higher than it would be in say, September, the height of hurricane season.  Tropical storms and hurricanes in the Gulf of Mexico aren't too off the charts weird in July, but it's still a bit unusual for things to be cranking this early.

The real trouble is the Mississippi River is very, very high from all the epic rains that fell upstream in the Midwest between March and June. So the water is now at around 16 feet, which is just a little below flood stage. A storm surge from wannabe Barry could push the water up over 20 feet, which would overtop levees and potentially give us Katrina all over again.

Another levee system that kept the waters of the Gulf of Mexico out of New Orleans led to the Katrina calamity of 2005. This potential mess would be different, as the water would be from the river, not the Gulf.

Of course, this is all a big maybe at this point. Maybe the surge won't be that big. Maybe Barry won't get very strong. Maybe Barry's path will take a turn so that New Orleans need not worry about anything.

Some forecasts say the unusually high water temperatures in the Gulf of Mexico might prompt Wannabe Barry to grow much more intense than current estimates. Winds in the upper atmosphere over the northern Gulf of Mexico will also become lighter, another sign that this could get pretty big pretty fast.

On the other hand, there the winds in the upper atmosphere might be stronger than forecast, or there could be intrusions of dry air, or wannabe Barry could travel closer to land during its formative stages, all of which could hobble this storm and make it not that much of  a powerhouse.

The track of the storm, which will be key on who gets the worst of it, is still a wild card, too. Nobody is sure where this thing will go.  

Yesterday, when flood forecasts put the storm surge flood expectations at 19 feet, not 20 feet, officials were sanguine about everything. Even at 20 feet, workers can reinforce levees and close flood gates to stave off flooding.

All this means that another catastrophic flood in the New Orleans area is not a done deal. At all. But it's enough to make me and a whole bunch of other people worried.

Plus, this morning's flood was no walk in the park. There's lots of damage in and around New Orleans from today's inundation. We can all hope that this turns out to be the worst of it.

As anybody in Nebraska, or California, or Washington DC or Kansas or Oklahoma or Ontario or Quebec can tell you, we've had enough flooding disasters lately.

Lake Champlain Flood Continues, Won't Go Away Soon

Lake Champlain has been above flood stage since Sunday morning, and the high water isn't going to end anytime soon.

Floods along the lake tend to last days and weeks anyway, as so many rivers and streams feed in. There's only one outlet - the Richelieu River in Quebec It's like pouring multiple buckets of water into  a bathtub with the drain open.

You can fill a tub that way faster than it will drain. The same is true with Lake Champlain.

As of this afternoon, Lake Champlain was at 100.63 feet, or about six-tenths of a foot above flood stage.

At least the lake has pretty much stopped rising, at the moment. A USGS graph shows the water level not changing much since late yesterday. It's up just 0.03 feet in the seven hours ending at 2 p.m., which is just a rounding error.

Rainfall last night was probably not enough to add much of an additional surge to Lake Champlain, if anything. Snow melt from the mountains probably added a little extra runoff during Tuesday afternoon's warm temperatures.  That rain and snow melt probably delayed a flood crest, though.

The rise in Lake Champlain's lake level was stalling at just
above 100.6 feet today. It's more than a  half foot above
flood stage. When it starts receding that process will be slow. 

Cooler weather that is expected to be locked in for a week or so probably means what little snow remains in the mountains will not melt much. In fact, new snow was falling on some peaks today, including the summit of Mount Mansfield.

The weather pattern will remain unsettled and frequently showery, which would further delay or slow any retreat of Lake Champlain flood water.

We'll need to watch a storm on Friday, which has the potential to a least slightly increase the flow of water into Lake Champlain. Beyond that, it's too soon to tell whether any storms will have an influence on the flooding.

While the lake is flooding, the biggest danger from any real damage is if we have particularly windy days, which would send battering waves against shorelines, causing erosion, road damage and possibly even damage to lakeside camps.

Northwest winds were causing one to two foot waves today. The next real chance of bigger waves comes Saturday, when expected northwest winds could create three-foot waves.

If you want a brighter side, at least this Lake Champlain flood won't be nearly as bad as the worst on record, in 2011.  The flooding that year came from a combination of a deep, moisture rich mountain snow pack and record amounts of rain in April and May.

We certainly won't have record amounts of rain this month, and the risk of such rainfall records next month is minimal at best.

Dangerous "Atmospheric River" To Cause Mid-Atlantic, Northeast Flooding

Three to seven inches of rain, and locally higher amounts, are
likely, especially in the red areas of this map during the next seven days.

An atmospheric river is set to dump tremendous amounts of rain on a broad strip running north and  northwestward off the Atlantic Ocean through areas around North Carolina and Virginia, northward through Pennsylvania and central New York. 

That means these areas need to be really, really on guard for serious flooding over the next few days.

First, we need to define for us all what an atmospheric river is. I'll let NOAA do it:

"Atmospheric rivers are relatively long, narrow regions in the atmosphere - like rivers in the sky - that transport most of the water vapor outside the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River.

When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow."

The problem is, atmospheric rivers often release extreme amounts of rain, causing extreme floods.

Atmospheric rivers are to blame for extreme floods around Nashville, Tennessee in 2010; and another extreme, deadly flood around South Carolina in October, 2015 that dumped up to two feet of rain in that state.

Not all atmospheric rivers are bad. They're common in California in the winter, and help replenish reservoirs and add to the snowpack in the Sierra Nevada mountains. Melting snow in the summer then keeps reservoirs and drinking water supplies at reasonable levels.

Like anything in weather, atmospheric rivers vary in intensity. Some aren't too tough to take, dropping a few inches of rain on a drought-stricken area, for example.

But often, they are terrible. And they can unload their tremendous rainfall well inland from wherer they come ashore -- like in the 2010 Tennessee flood I just mentioned.

The atmospheric river slated to hit parts of the East Coast this week is being created by a really wonky weather pattern now in place.

Usually this time of year, the jet stream, which controls the paths of storms and fair weather systems, sputters in a general west to east course near the United States/Canada border. In July, there's rarely much in the way of big southward dips or huge northward bulges in the jet stream.

There's an exception going on now and the weather pattern is really off the rails.  There's a big dip in the jet stream centered over the Great Lakes. This dip is causing unusually chilly weather for this time of year near the Great Lakes, and strangely severe storms in the South. Those storms created hail as big as tennis balls in Georgia and some other southern states.

Meanwhile, the Bermuda high is pushing a big heat ridge northward in the western Atlantic Ocean. Part of the Bermuda High has pushed as far north as Nova Scotia.

This is setting up the atmospheric river flowing northward from the tropics between the big Bermuda High to the east and the dip in the jet stream to the west.

This pattern is kind of stuck until later Thursday and Friday, when things will start moving. So the heavy rains will keep going over the same places from North Carolina  to New York through then. This could extend into southwestern Quebec as well.  Remember, this is tropical moisture, so any showers and thunderstorms can create one to two inch per hour rainfall rates.

This can cause life-threatening flash flooding. There was already destructive flooding and water rescues in Pennsylvania this morning.  That flooding will likely worsen this afternoon in parts of Maryland, Pennsylvania and the southern tier of New York.

We here in Vermont are on the eastern edge of this atmospheric river pattern. That means we are subject to the torrential downpours, but not the constant fire hose of rain. I noticed during a batch of rain that moved northward through Vermont this morning, an inch of rain fell on Rutland in just an hour.

We desperately need the rain here in Vermont, so precipitation this week is a good thing. We still have to watch out, especially Wednesday night and Thursday, when the axis of heaviest rain will probably shift to near or over the Green Mountain State.

Despite the dry conditions, an excessive downpour, or a series of downpours going repeatedly over the same spot, can cause dangerous flash flooding. It's impossible at this point to determine if, or even whether Vermont will see any flash flooding from this system.

The National Weather Service is eyeing the possibility of that happening, so stay tuned.

After A Brief Break, Another Hurricane Threat For The United States

Just some of the computer models for the future
track of what could well become Hurricane Nate.
As you can see by the variety of potential paths,
the forecast for Nate is still uncertain, but it
really does pose a threat to the U.S. Gulf Coast.

For a few blissful days, there hasn't been much in the way of hurricane activity in the Atlantic Ocean, and, thankfully, nothing to speak of near the United States except for a weak tropical disturbance near Florida.

Unfortunately, that started to change yesterday as a tropical depression formed near Nicaragua. That depression this morning strengthened to Tropical Storm Nate, which has a strong chance of becoming a hurricane.

Nate will likely cause big problems in Nicaragua and Honduras, Mexico, probably Cuba and, yes, the United States.

The tropical depression was having a hard time strengthening into Tropical Storm Nate early this morning because it was interacting with land over Nicaragua and Honduras. (Tropical storms and hurricanes only strengthen over warm water.)

Still, the storm is likely to cause dangerous flooding in those two countries today.

From there, Nate will head north and emerge over the toasty waters of the western Caribbean Sea, where it will likely strengthen. Before it gets too strong, the storm will likely clip Mexico's Yucatan Peninsula.

It's unclear whether what is now Nate will be a strong tropical storm or a hurricane by the time it gets to the Yucatan Peninsula sometime Friday night or early Saturday morning, but it will cause wind, flooding rain and possible storm surge problems there.

From there, Nate will move northward over the Gulf of Mexico toward the United States. The water in the Gulf of Mexico is very warm, which tropical systems love if they want to strengthen.

The big question is how much will this would-be hurricane strengthen before its inevitable landfall on the U.S. Gulf Coast.

Some models barely bring this to hurricane strength, it at all. Other computer forecast models dramatically strengthen Nate over the Gulf of Mexico, which would make it a terrible threat to parts of the U.S. Gulf Coast by late Sunday or early Monday.

This far out, its exact track is also uncertain, but a zone from Louisiana through most of the Florida Panhandle are at risk. Wouldn't you know this is an area that is relatively unscathed between the flood devastation from Hurricane Harvey in Texas and southwestern Louisiana, and the Florida Peninsula, which was raked by Hurricane Irma last month.

So, once again, the United States is bracing for a possible disastrous hurricane.

Up here where we live in Vermont, it's possible the remnants of Nate could affect us next week. On the plus side, if it does, it would dump a big slug of rain on us, which we need. (The relatively modest rains that fell over northern Vermont last night helped a little,  but we need a lot more to get over our current dry spell.)

On the negative side, a gusty, heavy rain from a former tropical storm could short circuit some of the fall foliage, which is finally beginning to develop over the North Country - much later than normal due to the record September heat we had.

I can't give you any specifics, since the track of Nate is so uncertain.

Vermont, New York Get Surprise Downpours, Flood Threat Dramatically Worsens

Chaos in Barre, Vermont after a May, 2011 flash flood.
There's some risk we could see scenes like this again this weekend.

Much more rain fell across northern New York and the northern half of Vermont overnight, and this sets the stage for a real flood threat.

The threat is even higher than I had been expecting earlier this week.

Last night's torrential rains, amounted to two to three inches, locally even a little more from the St. Lawrence Valley of New York, across Lake Champlain and the northern half of Vermont.

Burlington got 2.16 inches of rain and Colchester piled up 2.71 inches.

By the way, June rainfall in Burlington has so far amounted to 6.79 inches. If we don't get a drop of rain today, it'll still be the seventh wettest June on record.

Flood warnings were issued across a stripe of northern Vermont, along and roughly 30 miles either side of a line from Burlington to a little south of St. Johnsbury.

There's been no major flooding in that zone, but there is high water, washouts and that kind of thing.

Mainstem rivers are already getting into the act, too. There's a flood warning for the Winooski River at Waterbury. Today's flooding won't be as bad as during Tropical Storm Irene, when the Winooski flooded most of downtown Waterbury.

But low spots, and low roads are going to go underwater. Flooding will cover fields and damage crops downstream to Richmond, and possibly all the way down to the famed vegetable farms in Burlington's Intervale.

The rain was temporarily waning early this morning and the flood warnings will have probably been dropped, at least for awhile across northern Vermont by the time you read this. With the exception of the Winooski River flood warning, which will probably remain in effect most of the day, even if we don't get much more rain.

However, this flood event is only just beginning.

A flash flood watch is up across northern New York, the northern half of Vermont, northern New Hampshire and western Maine through Saturday night.

The warm front that caused the torrential rains last night is lifting toward Quebec and we'll get firmly entrenched in the warm, very humid air today.

Disturbances riding along a front to our west will fire up plenty of showers and thunderstorms this afternoon and evening, and some will of course have torrential rain.  Even as I write this at 7 a.m. Friday, heavy downpours were lurking in western New York, heading east.

Here's how high the risk is: It would only take about an inch of rain in an hour to cause a flash flood. Some of the thunderstorms today and even more numerous ones Saturday and Saturday night could easily drop two inches of rain in an hour.

Flash flooding in Richmond,  Vermont in June, 2013. This
kind of thing could easily happen again today, and
especially Saturday in Vermont. 

And some locations that are unlucky enough to get repeated storms could get three to five inches of rain between now and Saturday night.

We get flash flood watches fairly often, but this to me is the most precarious situation since the big spring and summer floods of 2011.

Some of today's storms could also be severe, with strong gusty winds. NOAA's Storm Prediction Center has Vermont in part of a broad zone of a slight severe storm risk today.

The storms will subside tonight, but there's still a chance of locally heavy downpours overnight.

For what it's worth, one weather model has a band of heavy rain lingering for several hours across northern Vermont this evening. That might or might not actually happen, but it's something to watch.

Saturday afternoon and night is looking even more dangerous. The cold front to our west will be closer, and the thunderstorms will be much more numerous Saturday than they will be today.

Even worse, the air will be even more humid than today, providing the fuel for even more torrential rains. And some of those storms could be severe, with gusty winds.

Not only is flash flooding a threat, but some of the bigger rivers in the North Country could flood. We already mentioned today's flood warning on the Winooski.

I wouldn't be surprised if the Winooski flooded again by Saturday, along with other rivers like the Ausable in New York, and Vermont's Lamoille, Mississquoi and Mad rivers. This all depends, of course, on how widespread and heavy the rain is.

So heads up. It's going to be a rough weekend. The threat of flooding is pretty damn high. We could get lucky and not get so many storms, but I'm not holding my breath. This could be one for the record books.

Tornado/Severe Weather Threat Growing Today In Parts Of The Midwest

The areas of the country in yellow and orange-especially the orange
areas, are at risk for tornadoes, strong thunderstorm winds and
large hail later today and tonight.

The chances of some tornadoes and severe thunderstorms is definitely growing for later this afternoon into tonight for parts of the Midwest, especially in Iowa, Missouri and the Ozarks.
Forecasters have been watching this area for the past few days, and things were definitely coming together as of early afternoon to produce some tornadoes, big hail and strong winds.

As always with severe weather outbreaks, it's hard to tell even a few hours in advance exactly how serious and widespread any tornadoes get.

But suffice it to say, look out if you live anywhere near this area. There is definitely a chance of tornadoes around there. Some of the tornadoes could be rather significant, as in on the stronger side with longer than average tracks.

As I wrote this early Monday afternoon, NOAA's Storm Prediction Center was poised to issue a tornado watch for most of Iowa.

I imagine tornado watches might be issues later for much of Missouri, northern Arkansas and western Illinois. In fact, there might end up being a slightly higher tornado risk in Missouri than in Iowa tonight. We'll see.

Some of these areas, especially in eastern Missouri and Illinois, dealt with some destructive tornadoes last week.

To the west of the severe storm risk area, a huge area of the Plains, from southern North Dakota all the way down to northern Texas and eastern New Mexico is under high wind warnings today.

Gusts could reach 70 mph, there's already reports of a lot of blowing dust and tractor trailers have been blown over in some areas. There's a high wildfire risk in parts of these areas.

No rest for the weary, I guess.

Update On New Round Of Severe Storms, Record Warmth

Areas in yellow and orange are most at risk for severe
thunderstorms and tornadoes today and tonight.
A few strong tornadoes are possible. 

It looks like it's going to be a dangerous afternoon and evening across the middle of the United States.

Another burst of warm air has engulfed the eastern half of the nation, and a storm in the middle of the country is about to spawn another round of severe thunderstorms and tornadoes.

This outbreak looks like it will be more widespread than the one that hit last weekend, and it could also be worse, with more and stronger tornadoes than the ones that struck Saturday in the Northeast.

It all depends upon how the atmospherics come together.

At this point, the areas that seem to be at greatest risk of severe storms and tornadoes is northern Arkansas, the eastern half of Missouri and most of Illinois and Indiana.

It's possible some of the tornadoes will become quite strong - EF3 or higher- and those are the ones that cause the most damage, and created the highest risk of casualties.

It looks like each individual storm that forms today and tonight will move along quite quickly, so if any of these contains a tornado, there won't be a lot of time for people in the path of the storms to take shelter.

Also, this is hitting on a weekday, when more people are out and about going to work, school and errands. Generally speaking, more people are at home on weekends like during Saturday's rough weather, so there's a better chance they will be in a place where they'd hear a weather radio or a TV station will sqawk out a warning.

Areas in yellow and orange are most at risk for severe
thunderstorms Wednesday. A few tornadoes are possible
in the yellow and orange zones. 

On Wednesday, the severe weather moves east, probably covering a large area from Alabama and Mississippi to near New York City.  

Strong straight line winds and big hail are the biggest threat tomorrow, but I would not at all be surprised to hear of a few tornadoes in this zone during the day Wednesday.

As the storm rides on by, more record heat is expected in the East, from Florida all the way to northern New England.

VERMONT EFFECTS 

Here in Vermont, record highs are endangered again tomorrow. It won't get up to 72 degrees like it did Saturday, but Wednesday's record high of 59 degrees in Burlington is definitely under threat.

There will be a fairly decent slug of rain coming through Wednesday and Wednesday evening, possibly accompanied by some rumbles of thunder again.

I would not be at all surprised if we get more low land flooding out of this, just as we did Saturday and Sunday.

The good news is most of the ice has been flushed out of the rivers, so the risk of ice jams is lower. And there's not as much snow to melt and add to the rivers as there was over the weekend.

It'll turn sharply colder Thursday night and it's back to winter Friday and Saturday with temperatures actually a little below normal.

After that, I don't see any real signs of any more record heat for the forseeable future.

Tornado Watch Possible In N. New York Ahead of Autumnal Cold Front

Areas shaded in yellow are at risk for severe storms
later today and tonight. Areas in dark green have a
marginal chance of severe weather. In Vermont, if there
are any bad storms, it would hit later tonight. 

UPDATE 3:30 P.M. SATURDAY.

As of 3:15 p.m. Saturday, NOAA's Storm Prediction Center was considering issuing a tornado watch in northern New York for later this afternoon and early tonight.

The tornado watch, if it is issued, would cover New York's St. Lawrence Valley and the western and central Adirondacks.

A couple of tornadoes are also possible in southern Ontario.

Strong winds aloft, winds that shift directions at different heights, could touch off a few rotating supercell thunderstorms along and just south of a warm front that's now moving northward through the region.

It's possible that if these supercells develop, they could create a tornado or two.

At this point, it looks like the storms will weaken somewhat as they move into Vermont tonight, but there is still a chance of strong, damaging wind gusts in the Green Mountain State tonight. The risk of tornadoes in Vermont with this is very low.

If there are strong, damaging winds with storms in Vermont tonight, they're most likely in the northwestern half of the state.

PREVIOUS DISCUSSION

There are actually Vermonters who are done with this never ending summer. Done with the heat and humidity.

They're ignoring the fact that we will eventually have our long, cold winter to contend with, but whatever. 

Fans of cooler weather can rejoice, though: We have one more humid day coming today, one more round of potentially strong thunderstorms feeding off that humidity, and then September weather will arrive a week and a half late.

The details:

A warm front will come through Vermont today from the south. It's the remnants of that weak "cold" front, which wasn't that cold, that came through Friday morning.

Anyway, we'll be back in the soupy air by this afternoon, and we'll have to endure a terribly muggy night tonight just as we did Thursday night.

But a cold front is coming and it's got some ooomph. It won't come through Vermont until early Sunday morning. That's a good thing, despite tonight's humidity, because it it would come through earlier, it would trigger some strong to severe storms this afternoon and tonight, possibly quite a few of them.

That won't be the case. Still, we might get some strong storms later tonight. because as I said, this cold front is fairly strong and has some pretty strong upper level winds with it.

The Storm Prediction Center has a slight risk of severe storms late today and tonight across northern New York and a marginal risk in western Vermont.

The thinking is the storms will get going in Ontario later today and move east. (There might be a couple of tornadoes in Ontario today. They've had a busy time with tornadoes there for the past month or so, go figure)

 Some of the storms that do get going will be able to grab those strong upper level winds up above and drag them down to the surface. That means the possibility of damaging wind gusts, especially across northern New York tonight.

The Storm Prediction Center said there's a chance that some of the storms in New York might start spinning, so there's a very minimal chance of a brief tornado in the St. Lawrence Valley and northern Adirondacks tonight.

This is the same system that set off a few tornadoes in Illinois Friday, but of course any twisters in the Northeast are less likely than they were in the Midwest Friday.

The storms will weaken somewhat as they get into western Vermont a little before dawn then sweep across the rest of the state during the first half of Sunday morning.

Some of the storms might set off some gusty winds that could locally take down some trees and power lines. The storms could produce briefly heavy rain, so you might get a half inch or a little more rain in a few spots.

That's not much drought relief, especially since the rain, where it falls, will come down in a sharp heavy burst and not be the kind of slow soaker we'll need.

You'll totally feel a change in the air Sunday after the cold front goes by. It will be cooler and less humid. September-ish.

Sunday night, areas that haven't seen temperatures below 50 degrees since mid-June will probably get into the 40s.

It'll turn warmer - but not summery - Monday and Tuesday before the next strong cold front gets here.

High temperatures will only make it into the 60s Wednesday and Thursday, and we might well get our first frost of the season in the cold hollows of New York, Vermont and the rest of northern New England.

The frost won't be widespread, but tis the season!

Destructive Tornadoes Possible On Plains Today

Severe storm near Brule, Nebraska Friday.
Photo by Brett Wright on Twitter @WxMstr  

NOAA's Storm Prediction Center has a moderate risk of tornadoes today, especially in much of Kansas and Oklahoma.

This could easily be one of the worst outbreaks of severe weather so far this spring, maybe even the worst.

It just depends upon whether the tornadoes cooperate, or mow through urban areas like around Wichita, Kansas or Oklahoma City.

The Storm Prediction Center says some of the tornadoes today could be "significant and long lived." so people in the areas under threat ought to keep an eye to the skies and have a path cleared to the tornado shelters, just in case.

Thunderstorms early this morning might have disrupted the potential for the big tornadoes a little bit later today, but the atmospheric energy entering the picture should be more than enough to stir up some really bad weather.

As a preview to today, there were nine reports of tornadoes on Friday, one of which caused three injuries in Texas.

 Here's a large tornado near Torrington, Wyoming yesterday:

Today's Threat of Severe Weather In Plains Greater Than Yesterday

NOAA's Storm Prediction Center has
 a broad area under risk of severe storms today
with a particularly concentrated risk
over parts of Oklahoma.  

Yesterday was the unofficial start of severe weather season in the United States.

Belated, because as I've noted, the month of March had until now had virtually no severe storms, which is very unusual.

You can tell there was a pent up "demand," if you will, for severe storms, as it seems there were zillions of storm chasers driving willy nilly around Missouri looking for the most photogenic storms.

I hate to use the word "demand." That's why I put it in quotation marks. I'm sure the people who suffered property damage to roofs and cars from hail that was bigger than golf balls in some towns weren't exactly "demanding" a hail storm.

But, to put it crassly, there's also a market for severe storms and the storm chasers were taking advantage of it. I'd much prefer there be no destructive storms and no property damage ever, but it's going to happen.

So the storm chasers go out and capture the drama, for better or worse.

The NOAA Storm Prediction Center said there were no reports of tornadoes or significant wind damage from the storms in Missouri yesterday. Some storms got to rotating, and there was a tornado warning or two, but there have been no reports of any twisters touching down.

However, on Tuesday there were no fewer than 70 reports of big hail, mostly in Missouri in Arkansas.

The storm chasers will be out in force today, because the risk of severe weather is greater and more widespread than it was on Tuesday.

The main threat once again will be hail and strong winds, with a much lesser chance of tornadoes. That said, there is a somewhat greater chance of tornadoes than yesterday.

This is especially tree in northeastern Oklahoma, northwestern Arkansas and extreme southwestern Missouri, where supercell thunderstorms, separate from a main batch or line of severe storms, could produce a couple of tornadoes.

In that region, there's a 5 percent chance of a tornado within 25 miles of any given point in the area I outlined. For that neck of the woods, the 5 percent chance isn't all that high, so we're definitely not talking about a major, widespread tornado outbreak here.

Then again, it only takes one nasty tornado to trash a town, so let's hope that if any tornadoes do form, they stay out in open country away from where anybody lives.

The risk of severe weather is upgraded by the NOAA's Storm Prediction Center to Moderate in parts of Oklahoma, Arkansas and Missouri. That's the second highest level of risk the storm center puts out when it assess the chances of severe weather on a daily basis.

Hail is a particular concern. I noticed the Weather Channel's Jim Cantore is advising people to try and avoid Interstate 44 in northeastern Oklahoma after 2 p.m. today because that area seems to be under the greatest threat from hail.

Overall, there's a chance today and tonight of damaging thunderstorms from northern Texas, most of Oklahoma, the northwestern half of Arkansas, southern Missouri, extreme southern Illinois and Indiana and extreme northwestern Kentucky.

Things should settle down tomorrow as the storm system causing this heads to the Northeast.

I'm still watching for the possibility of some local flooding in parts of New England Thursday afternoon and night as rain from the storm moves in and starts to break up river ice, leading to the possibility of ice jams.

There could be a fairly strong thunderstorm or two in the southeastern United States Thursday and in Florida Friday, but nobody is expecting anything widespread.

The chances of severe weather anywhere in the United States look pretty low into the middle of next week as well.