Dallas is swallowed by a massive ‘rain bomb’

DFG4HXAMDA633PVX45S6SROBDA.jpg
Heavy rains and storms left parts of Louisiana underwater due to severe flooding June 6.

June 9, 2017

I feel like we need a sound effect for this one. Would it sound like a whoosh? Maybe a crashing wave?

It’s not every day you see a textbook microburst like this one caught on camera, but Toddy Jack managed to get this insane photo on Sunday afternoon. At the time, Dallas was getting drenched with heavy rain as this nearly stationary storm sat over the area. Then it finally and literallyunloaded all of its precipitation in a giant “rain bomb” — right over downtown.

A microburst is a sudden but powerful area of sinking air, associated with the downdraft area of a thunderstorm. While microbursts are typically small, and 2.5 miles in diameter or smaller, they can do incredible damage. Microbursts can have wind speeds in excess of 100 mph, and have been known to do so much harm that the destruction left behind can be mistaken for tornado damage.

A microburst occurs when a thunderstorm simply can no longer “hold” its precipitation. Think of it as being like a brown paper grocery bag. When the bottom of the bag can no longer support the weight of the groceries within, it breaks and all your apples, oranges, etc. fall and spread out all over the floor. Microbursts behave the same way.

When an updraft is strong, it can hold and suspend large amounts of rain droplets as well as hail within the cloud. When the updraft weakens, as is especially typical with a vertically stacked summertime storm, it can no longer hold that rain and hail within. Eventually, the updraft collapses, and all the precipitation crashes to the ground and spreads out in all directions.

While microbursts can do extreme damage to buildings and landscapes such as forests and croplands, they are especially dangerous for aircraft. It is impossible to predict when and exactly where a microburst may occur during a thunderstorm, which makes planes that are either taking off and especially landing (times when the planes are closest to the ground) susceptible if caught in one of these powerful downdrafts. Unfortunately, several fatal airline crashes in history can be attributed to microbursts.

There are actually two types of microbursts: wet and dry. Wet microbursts are most common in the Southeast during the summer months, while dry microbursts are more common over the West. The storm over Dallas on Monday was a wet microburst, as seen by the dark rain curtain spilling out of the cloud.

Microbursts are also known for the visual feature called “rain foots” (think Elf Shoes) that occur when the rain and/or dust hits the ground, then curls back upward as it spreads out horizontally on each side.

 

Stunning video of a ‘particularly dangerous’ tornadic storm from 22,236 miles in space


View of tornadic thunderstorm Sunday over the Texas Panhandle from GOES 16 satellite. (NOAA Satellites)

May 6 at 3:07 PM

 

 

What does a tornadic thunderstorm look like from space? The GOES-16 satellite captured a stunning view of a Texas supercell Sunday evening as it dropped a photogenic twister amid a busy day for severe weather in the Plains.

The twister struck just east of Tahoka, a community of 2,600 about 20 minutes south of Lubbock. It quickly grew into a large tornado, with the National Weather Service warning, “This tornado is wrapped in dust and rain and may be difficult to see.” The warning was labeled PDS — a rare “particularly dangerous situation.”

No injuries were reported, but the storm damaged power lines and barns and tore the roof off a home, according to EverythingLubbock.com. The tornado was one of 23 reported to the National Weather Service between Texas and Nebraska on Sunday.

Video shot by storm chasers shows the tornado dancing elegantly and ominously as it becomes enshrouded in rain, hail and dust. The dust acts as a tracer showing the pattern of the winds near the surface as they feed into the vortex from all angles. It’s a remarkable scene — but 22,236 miles above the surface, the view was equally impressive.

The GOES-16 satellite tracks cloud-top temperatures, a good indicator of just how high is a cloud. As the cap (a stable air layer that prevents early storm formation) erodes and storms explode, towers can be seen billowing upward like steam penned up beneath a lid in a pot of boiling water.

To better understand this feature on satellite, imagine holding a flaming lighter a few inches beneath a giant piece of white paper. The spot of paper just above the lighter would quickly become discolored and eventually burn. Then imagine moving the paper, as though it’s being blown by jet steam winds. Now instead of a burn, there’s a dark stripe marking all the places torched by this heat source. That’s kind of how an intense anvil can stretch so far downstream of a very localized heat source.

It’s important to note that the towering anvil cloud is not a hot plume, rather, a thick cloud of frozen particles (ice crystals and snow flakes).

Remnants of the storm’s anvil are carried hundreds of miles downwind, over long distances by the strong jet stream winds. Meanwhile, a constant plume of upward motion farther west sustains the behemoth storm, its updraft plume marked by a bubble of red colors. That’s the “overshooting top” — the product of an updraft so strong the storm punctures the tropopause — ordinarily an effective “ceiling” or stable layer for weather systems. But when a pocket of air rises with enough momentum, it struggles to put the brakes on even when it shouldn’t be able to rise. That’s a surefire sign of a vicious storm.

As a result, the cloud tops are extremely cold since they reach so high. Some may appear a bit warmer because of contact with the stratosphere — a region about 10-12 miles above the ground where temperature climbs with height.


A 3-D radar view of tornadic thunderstorm Sunday over Tahoka, Tex. (GR-2, adapted by Matthew Cappucci)

 

 

At the same time, ripples can be seen propagating throughout the anvil. These are little waves in the upper atmosphere caused by disturbances originating from the turbulence around the overshooting top. It would be like diving to the bottom of a pool and then blowing a really big bubble. When that pocket rises (less dense) and then hits the top, concentric wavelets would ripple outward from the center.

Ground-based radars offered an equally remarkable perspective, peering into the storm and noting a rain-free void where the updraft was so intense that precipitation was unable to fall. Dust along a boundary wrapping into the tornadic circulation can be seen, as well.


Close-up 3-D view of tornadic thunderstorm Sunday in Tahoka, Tex. (GR-2, adapted by Matthew Cappucci)

 

 

They’re images that combine natural beauty with raw destructive power, and similar scenes may unfold on the Plains in the days ahead. Following scattered afternoon storms Monday, a more significant severe weather event could play out Tuesday and Wednesday.

Trump administration has EPIC plan to develop the world’s smartest weather forecasting model ~ The Washington Post

NASA visualization of Hurricane Sandy. (NASA)

April 23 at 5:00 PM

It was October 2012 when the European weather prediction model beat its American counterpart in forecasting Hurricane Sandy’s hard left turn into the U.S. coastline. What scientists had known for years — that the European forecast model was superior to the American — caught the attention of the U.S. public and Congress.

Since then, the National Oceanic and Atmospheric Administration, with funding support from Congress, has worked intensely to improve the American model. It has boosted its computing power, improved the way it brings in data, and enhanced how it simulates weather systems at small scales. Yet, more than six years later, it still trails the European model in overall accuracy.

Neil Jacobs, the acting head of NOAA and a meteorologist, is committed to closing the gap between the models. Since being appointed to the Trump administration, he has made one of his top priorities installing a process that will allow U.S. forecast modeling to reach its potential and become world-class.

As part of its 2020 budget request, to the tune of $15 million, NOAA has proposed the establishment of the Earth Prediction Innovation Center (EPIC), which it says “will advance U.S. weather modeling and reclaim international leadership in the area of numerical weather prediction.”

In an interview, Jacobs blamed recent U.S. modeling shortfalls on a lack of research investment. He said the United States now spends about the same amount on operating its flagship model, the Global Forecast System (GFS), as it does on research initiatives to improve it. By contrast, the European Center for Medium-Range Weather Forecasts spends roughly five times as much on research. Jacobs said he’d like to see NOAA “grow research five times” to keep pace.

This is where EPIC comes in.

~~~  MORE  ~~~

Avalanche Forecasters Say Rocky Mountain Region Now At Higher Risk ~ NPR

FROMAspen Public Radio

Storms sweeping across the Rocky Mountains this winter have caused the highest avalanche danger since the ratings started in 1973. More than 3,000 avalanches already have taken place in Colorado alone, and they’re unusually large.

White River National Forest lies just outside of Aspen. Part of the forest is known as Highlands Ridge.

The valley below that ridge is now buried because of an avalanche. The snow is deep enough that treetops barely poke out. The trees that aren’t buried haven’t fared much better.

“Old 50-foot, 60-foot, 70-foot trees have been snapped like toothpicks,” says Zachary Paris, property manager for the house at the bottom of two new avalanche paths below the ridge.

A one-mile-long section of Highlands Ridge collapsed under its own weight earlier this month, sending a cascade of snow and debris onto the valley floor below.

“We’re probably standing on a 20-, 30-foot pile right now,” Paris says.

More avalanches, larger avalanches

The Colorado Avalanche Information Center estimates that the Highlands Ridge slide could be the largest in almost 300 years and that it reached speeds of more than 110 miles per hour.

“We’re seeing much more of these large and destructive avalanches,” says Brian Lazar, a deputy director of the center.

Avalanches are rated on a scale out of 1 to 5. The Highlands Ridge snow slide was a 4.5. It’s just one of the hundreds of record-breaking slides triggered in Colorado’s high country so far this year.

“We saw more in the first 10 days of March than we’d typically see in a five-year period,” Lazar says.

His research suggests that, as the climate warms, wet snow avalanches like those he’s seeing now could start two to four weeks earlier than normal. That means a longer avalanche season.

“We’re certainly starting to see weather patterns which are intimately tied to avalanche activity that is different than what we’ve seen in past years,” Lazar says.

Longer avalanche season

A longer season with warmer weather means an uptick in slides is likely, which makes controlling avalanches in ski areas like Aspen difficult.

Aspen Ski Patrol uses charges — little bombs — to trigger slides in controlled conditions to prevent catastrophic and deadly avalanches. These explosions can be heard from downtown Aspen after a big snow storm.

Aspen Ski Patrol doesn’t release specifics about how many blasts it sets off for avalanche control, but it does say it’s increased the number of charges this season and spent more time mitigating avalanches.

Avalanche season isn’t over. According to Lazar, as temperatures go up, so can avalanche danger

He says when “things start to melt, we can see a spike in wet avalanche activity.”

That means Colorado can expect to see more slides in what has already been a record-breaking season.

Silverton officials close county roads, discourage backcountry use

It does not appear crews will trigger avalanches on Kendall Mountain
The Colorado Department of Transportation triggered a slide in 2013 along U.S. Highway 550 near Silverton. The town of Silverton and San Juan County are considering whether to close the backcountry to recreationists because of considerable avalanche danger.