Another Weather Off The Rails Weekend (Not In Vermont, Though)

From 9 News:  A severe thunderstorm associated with a derecho
knocked this billboard down on a Denver building Saturday. 

As we forecasted yesterday morning, weather is definitely going off the rails in different parts of the nation this weekend, and that trend will continue for the next few days.

We here in Vermont will pretty much be an island of tranquility in the weather department, but that won't be the case elsewhere.

The most remarkable weather event Saturday was a long lasting derecho that got going near the Arizona/Utah border and raced north and northeastward during the day through the central and eastern Rocky Mountains and on into the western Dakotas.

Derechos are relatively rare events and almost unheard of in the Intermountain West. Yes, I know we just had a derecho in Pennsylvania and New Jersey last week, but they still don't happen all that often.

On average derechos happen once every year or every other year in much of the Midwest and South. On the East Coast, you average one every four years or so.  In the Intermountain West, there have maybe been a handful over the past several decades.

The one that swept through yesterday was a doozy, too, judging by wind reports. Just a sampling:

110 mph near Copper Mountain, Colorado
94 mph Butte County, South Dakota
92 mph near Cactus Plateau, South Dakota
85 mph, Four Corners, Wyoming

There were numerous reports of gusts above 75 mph, including in metro areas like Denver.

Meanwhile, Florida got in on the action, thanks to Tropical Storm Cristobal.  Most of the heavy weather with this system was east of its center.  This mass of storms spun off at several tornadoes in Florida, including one that passed through Orlando.

The Orlando Sentinel reported that at least 50 residents of apartment blocks and houses were displaced near the city's downtown because of tornado damage.

MORE ROUGH WEATHER COMING

Tropical Storm Cristobal will splash ashore around Louisiana later today. Storm surges and flooding is already happening in Louisiana and Mississippi, and that will continue the rest of the day.

However, the bigger drama from Cristobal will come over the next few days, as its remnants head north through the Arkansas, Missouri and into Wisconsin by Wednesday.

It won't really be a tropical storm by the time it hits the Great Lakes, but it will manage to intensify. It'll form into a mean storm for this time of year over or near Lake Superior.  Expect reports of wind damage, battering waves and erosion on the lakes and maybe some flash flooding.

VERMONT CALM

All this weather action will pretty much miss Vermont. The fact that Cristobol will be going by to our west will give us a squirt of warm to hot, and windy weather midweek, but nothing extreme.  Not a lot of rain is in the forecast either.  A cold front associated with the remnants of Cristobol might bring a few showers and thunderstorms late Wednesday night and Thursday.

Cristobal Bubbles, PA/NJ Slammed, Norway Slides

Badly damaged house in New Jersey following yesterday's derecho.
Photo by Jessica Beym, NJ Advance

While tropical weather geeks keep their eye on Tropical Storm - now Tropical Depression - Cristobal, there's been plenty of weather ation in the United States and elsewhere.

Dramatic videos are the botoom of this post. One of the shows an incredible landslide in Norway I'll get to in a minute,  

DERECHO AND SUPERCELLS

In Pennsylvania and New Jersey, a derecho swept southeastward from near Lake Erie across the Keystone State and finally off the Jersey shore during the late morning and early afternoon Wednesday.  This was followed in the late afternoon and evening by supercell thunderstorms that prompted a tornado warning in Philadelphia.

Winds gusted to 65 mph or so both during the early afternoon derecho and the evening tornado warned storm.  I don't think Philadelphia had ever previously had two 60+ mph storms on the same day.

A derecho, by the way, is a long lasting, fast moving line of severe thunderstorms that almost always cause severe wind damage. That was the case yesterday. The official definition of a derecho is a line of storms that survives over a distance of at least 240 miles and produces peak winds of at least 58 mph over most of its path.

This derecho produced winds of up to 89 mph in New Jersey, with gusts in the 65 to 80 mph range thorugh a long swath of Pennsylvania and New Jersey.

The derecho killed at least three people, including one at a golf clubhouse that was hit by an immense falling tree.  Many homes were damaged, most by falling trees. A large apartment complex lost its roof.

A derecho usually stablizes the air immediately behind it, so it was remarkable that the atmosphere recovered enough to produce those supercells over Pennsylvania and New Jersey in the evening.  Those storms just added to the damage and the power outages.

Tornado-warned storm over Philadelphia last evening. Photo bu
Ashley Corin 

And - just what they need - more severe thunderstorms are possible today in parts of Pennsylvania, New Jersey and Maryland.

CRISTOBOL

Cristobol has been downgraded for now to a tropical depression as it meanders inland over souther Mexico.  It's still expected to take a northward turn, emerge over warm Gulf of Mexico waters, and strengthen somewhat as it moves north toward Louisiana by early Monday.

Intensity forecasts are really, really uncertain, but at least for now, it's not expected to reach hurricane status before landfall.

LANDSLIDE

The following isn't directly related to weather, but wet weather could have contributed to it.  A huge landslide 2,000 feet wide and 500 feet wide swept at least eight houses out to sea along the northern Norway coast.

Miraculously, nobody was injured, as most of the houses were vacation places and people had left after the weekend.  A dog was rescued in the afternmath of the landslide.  Scroll down a ways for the incredible video.

Here are some videos, first with scenes from the Pennsylvania storms:



Another view of the storm's intensity



Let's go overseas to Chcchnya, which had its own battle with severe weather:



Here's the Norway landslide. I was oddly rooting for the big white house to survive, but I knew that was impossible

New Twist In Nation's 2019 Severe Weather Hell: A Derecho

Damage reports extending from Colorado to South Carolina Friday
along the path of a derecho.

As many parts of the nation continues to reel from severe storms and flooding that seem to go on and on, we had one more type of storm chaos to deal with this past week. A derecho.

Derechos are long-lasting, long-tracked thunderstorm complexes that are capable of lots and lots of damage. That's especially true because they cover quite a lot of real estate.

Here's the officials definition of a derecho from NOAA:

"By definition, if the swath of wind damage extend for more than 250 miles, includes wind gusts of at least 58 mph for most of its length and also includes several well separated 75 mph or greater gusts, then the event may be classified as a derecho."

It appears Friday's storm complex, which originated over Colorado late Thursday night and finally moved off the coast of far distanct South Carolina early Saturday, will be classified as a derecho.  This path was unusually long, even for a derecho. It went on for more than 1,000 miles before finally falling apart off the South Carolina coast.

Friday's derecho killed at least 3 people along its path, the Weather Channel reported. There were a good 550 reports of damage across the nation Friday, mostly along the path of the derecho.

Derechos can produce tornadoes, but most of the damage from them is from straight line winds. This was true of Friday's storm complex. Six tornadoes were reported, but most of the severe weather reports were of straight line winds.

Damage reports were spottier in Colorado and Kansas in the initial phase of the derecho. I think that's mostly because it went through sparsely populated areas so that not as many people were there to report on it

The derecho picked up steam later Friday as it past southeastward through Missouri, southern Illinois, Kentucky, Tennessee, Georgia and South Carolina.

Derechos aren't very common, to be honest. There's usually only a couple or a few in the United States every year, if that.

That's good, because derechos can be very expensive, not to mention deadly. Remember, they cover a lot of ground, so there's usually a huge number of people and property in the way of these things

There's no word on the dollar amount of damage of Friday's derecho, but some past ones have been really notable. A June, 2012 derecho that started in Iowa and moved east and southeastward through the Mid-Atlantic states killed 22 people, caused $2.9 billion in damage and cut off electricity for 4 million people.

Derechos are rare in Vermont, but can happen. On average, Vermont can be expected to experience a derecho once every four years.

Perhaps the most notable derecho in modern times to affect our neck of the woods was in July, 1995, amid a record heat wave. (Derechos often get their a lot of their energy from extremely hot, humid air.)

There was actually a series of four derechos during one week across the northern United States in mid-July, 1995. The fourth one originated in the Upper Peninsula of Michigan and traveled southeastward through Ontario, New York, and on into southern Vermont and New Hampshire, and the rest of southern New England.

When this derecho crossed the Adirondacks, it leveled large tracts of forest and killed five people. There was also lots of tree damage in Vermont, mostly south of Route 4.

It's hard to tell when another derecho will develop. Suffice it to say there's plenty of severe weather once again in the middle of the nation today. No word yet on whether any of this will evolve into another derecho.

That Midwest Severe Weather Outbreak Today Looks Really Bad

Areas in red and orange are most likely to experiemce
tornadoes and damaging thunderstorm winds today.  

A broad area around the southern Great Lakes and Ohio Valley is bracing today for a very dangerous weather day.

An unusually strong weather  disturbance for this time of year is interacting with very hot, very humid air to create the risk for tornadoes, a few of which might be strong, very damaging winds, flash flooding and maybe even a derecho.

Derecho are relative rare, and are often more dangerous than tornadoes or individual severe thunderstorms because they cover such a wide area.

Most areas in the eastern two thirds of the United States experience a derecho once a year at most. Almost all areas get them less often than that, maybe one or two every four years.

According to NOAA's Storm Prediction Center, a derecho is defined as a swath of wind damage that extends for more than 250 miles, which includes quite a few locations within the derecho's path of gettings gusts of at least 58 mph,  and also several well-separated 75 mph or greater gusts.

Sometimes winds in a couple spots along a derecho's path can get ridiculous. One derecho in May, 1998 created a wind gust of 128 mph in southern Wisconsin.

Derechos move forward fast - often between 50 and 70 mph -  so they come on you suddenly. They're particularly dangerous in urban areas, since they toss down lots of trees and power lines that hit houses and cars and cause long-lasting power outages.

Whether or not a derecho gets going with this outbreak or not, things will get dicey in the southern Great Lakes and other parts of the Midwest.

They already are dicey, in fact. Heavy thunderstorms over eastern Iowa with this storm system early this morning have caused some flash floods.

But the real dangerous stuff starts this afternoon. Initially, some supercell thunderstorms, with the potential for a couple strong tornadoes, will get going in eastern Iowa or northwestern Illinois.

The storms will then evolve into a line of bad storms barreling east to southeast across Illinois, Indiana and Ohio. That might be the derecho we're talking about. Even it it ultimately does not meet the definition of a derecho, many communities along the path of the storms will get strong damaging winds, sometimes in excess of 70 mph.

There will be a tornado threat in this area as it comes through later today, too,  especially in eastern Iowa, parts of Illinois including in the southern half of the Chicago metro area, and maybe on toward South Bend and Indianapolis, Indiana and Columbus, Ohio, says the Storm Prediction Center

The complex of storms will plow through the central Appalachians tonight and possible into the mid-Atlantic states, where severe storms and a couple tornadoes caused damage yesterday.

Here's a video taken in 2011 that shows you don't need a tornado to make a storm like today's expected outbreak dangerous. These are straight line winds from a thunderstorm

 

Big Severe Storm Outbreak Skirts Edges Of Heat Wave Today

Areas in red in this map have the highest chance
 of seeing very severe thunderstorms and maybe
 a few tornadoes today.  

Tornadoes and severe thunderstorms packing destructive winds, hail, lightning nad flooding rains raked parts of the Dakotas, Minnesota and Wisconsin yesterday and last night.

The exciting batch of weather if anything is going to intensify as the weather system causing the storms slides southeast through the Great Lakes, Ohio Valley and into the Southeast.

This is a classic so-called "Ring of Fire" severe weather outbreak.

This refers to a common mid-summer weather setup in which a hot high pressure system sets up, in this case over the southern Plains. Around the northern periphery of these heat ridges, a ring of thunderstorms often sets up.

That's the "Ring of Fire" I talked about.

Sometimes on the northern or northereastern most part of the Ring of Fire, a particularly nasty batch of storms develops. Often, this becomes a derecho that races east or southeast into the United States.

I don't know if this case will result in a derecho, but as of early Monday morning, it looks like the severe storms were maybe organizing into one in Wisconsin. If this develops it wil race southeastward into Illinois,  Indiana and a good chunk of the Ohio River Valley.

A should step back and define a derecho. The official definition is that it's an intense line of storms that covers a distance of at least 250 miles, and inclues wind gusts of at least 58 mph along most of its lentgth, and has several, well separated gusts of at least 75 mph.

It's not unheard of to get reports of winds gusting to 110 or 120 mph in parts of some derechos.

A lot of us weather geeks and bloggers are reluctant to use the term "derecho" in advance of one because when you use the "D" word, it becomes the subject of a lot of media hype. After all, derechos are worse, more widespread and cause more damage than a typical, usually smaller line of severe summer storms.

Damage from a 2009 derecho in Carbondale, Ill.  

But in this case, it looks like there well could be an official derecho today, perhaps already beginning to be underway as of early Monday morning. We'll have to see it it is an official derecho after all is said and done tonight.

By the way, a derecho isn't the only dangerous risk today in the storm zone.

Supercell thunderstorms might get going ahead of the main band, or bands of thunderstorms. These can spin up tornadoes, and the region I've outline for today's severe weather could get a few tornadoes.

One or two of these tornadoes might end up being quite strong, says NOAA's Storm Prediction Center.    

Flash flooding is also possible in some of these areas, because the torrential rain associated with the storms will move over areas that have already gotten LOTS of rain this month.

Needless to say, watch out if a derecho gets going. Derechos are very dangerous, because they cover a wide area and often move over heavily populated areas.

One of the most famous recent derechos, in June, 2012 moved from the Great Lakes and Ohio Valley areas into the Mid-Atlantic states. It killed 22 people and cut power to at least 5 million people.

Some derechos can last a very long time. One of the worst was actually a series of derechos in July 1995 that extended from eastern Montana all the way to the New England coast.

One of these derechos crashed through Ontario and then into New York's Adirondacks late one hot night. Winds of 100 mph or more killed at least 5 Adirondack campers, and many more had to be rescued by helicopter as thousands or perhaps even millions of trees toppled in the extreme winds.

That derecho continued on into the Albany Capital District, southern Vermont and other parts of New England, causing widespread damage.

So you see, these things can be nasty. Very nasty.

If you're anywhere in a broad region between Wisconsin and the Carolinas today through tomorrow, keep  an eye to the sky and get indoors in a sturdy building at the first sign of storms or if you get a severe thunderstorm warning.

In many cases, these will be much more than the usual garden variety thunderstorms.

Derecho Scared Bejeezus Out of Chicago White Sox Fans, And A Team in Iowa

The tarp blows away in the face of severe thunderstorm
winds in Cedar Rapids, Iowa on Monday. 3 were injured.  

Last night's matchup between the Chicago White Sox and Los Angeles Angels was postponed due to that destruction derecho that swept across the Midwest yesterday and last night.

And in Cedar Rapids, Iowa, they waited a little too long to put a tarp out on the field ahead of the approaching storm, and chaos ensued.

Unfortunately, at least three people were hurt, but are expected to recover

In Chicago, before the White Sox game was called, people were waiting the storm out, but then this happened:



The scene in Cedar Rapids was worse, as the crew for the Kernels team had the tarp taken away from
tthem by winds of up to 70 mph. One person had the tarp roll right over him.

Lesson here: When there's a severe storm warning, it's better to take precautions well in advance of the storm actually arriving.

Here's the video: