The Northeast will have another round of accumulating snowfall early this week, right on the heels of the weekend winter storm.

For a heavily-populated area, this will be primarily a snowstorm and a disruptive one at that.

Snow is expected to start on Monday night in the mountains of Tennessee, then quickly spread across the mid-Atlantic and New England throughout Tuesday.

Most locations along the I-95 corridor from Washington, D.C., to Boston, will pick up 1 to 3 inches of snow from this storm.

However, along the the I-95 corridor there is the potential for 6 inches of snow to fall locally.

Unlike the storm this past weekend that brought a combination of snow, sleet and freezing rain to the region, precipitation looks to fall mainly as snow in the Northeast with rain farther to the south.

The Delmarva Peninsula is an exception to this, where slightly warmer air will allow for sleet to mix in with snow for a few hours.

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This snow will cause headaches for tens of millions of people on Tuesday across the I-95 corridor, especially those taking to the roads.

Snow can lead to slippery roadways, causing reduced visibility and a heightened risk of accidents. If you plan on taking to the roads, allow extra time to arrive at your destination and extra stopping distance when motoring along.

Those taking to the air should expect flight delays for inbound and outbound flights.

Snow will come to an end from southwest to northeast across the region Tuesday afternoon and evening as the storm quickly tracks off the East Coast.

MORE ON SKYE: Icy Storm Hits US, Affecting Many States

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For some people it's a mountaintop, for others it's a lapping seashore, but for Gayle Ferrell, the most serene place on Earth is 650 feet (198 meters) underground.

Ferrell works as the director of operations at a museum called Strataca, set in the abandoned tunnels of an active salt mine in central Kansas. The museum - which has access to about 300,000 square feet (28,000 square meters) of mined-out channels - has been open since 2007, but just unveiled a new attraction in November called the Salt Safari that brings visitors through an extended 3-hour-long sub-surface hike.

Clad in hard hats and carrying Mine Safety and Health Administration self-rescuer devices (breathing apparatuses used by miners in emergencies), visitors descend hundreds of feet in a freight elevator and enter a world covered in glittering, geometric salt crystals. [Album: Hike the Strataca Salt Safari]

A retired salt miner and the museum's maintenance manager together lead the group through the tunnels, explaining how the mining operations work and how the shimmering deposits formed.

"This is not a museum where you read boards and that's it," Ferrell told LiveScience's OurAmazingPlanet. "You go 650 feet underground. This is the only place in North American where the public can do that, and go into an active salt mine."

Wonder of Kansas

The museum was listed by the Kansas Sampler Foundation as one of the "8 Wonders of Kansas" in 2007, a list that includes several other natural wonders and culturally significant sites. Strataca has since drawn about 55,000 visitors annually from all 50 states, along with 25 countries around the world, Ferrell said.

Though she says she had held a better paying job at an accounting firm before joining Strataca several years ago, Ferrell has never regretted her decision to spend her days underground.

"It is a very serene and calming atmosphere, and time passes in a whole different dimension," Ferrell said. "Three hours seems like 30 minutes."

The salt deposits that make up this unique environment formed about 250 million years ago, when modern-day Kansas sat close to the equator and was more arid than it is today.

"It would have been a hot environment without a lot of rain," Shane Lyle, senior research assistant with the Kansas Geological Survey, told LiveScience, comparing the area's ancient climate to that around the modern-day Arabian Sea. (Lyle informally advises Strataca on geologic content in its exhibits.)

During that ancient time, a body of water called the Permian Sea covered large parts of what is now North America. The site of the salt mine formed a shallow embayment to the north of the sea, cut off from the larger body of water.

Through time, water evaporated from the isolated body of water, leaving salt behind. Eventually, the salt became so concentrated that it fell out of solution and formed crystals on the seafloor, Lyle said.

Buried salts

Over the course of millions of years, the embayment and the rest of the Permian Sea cyclically dried up, flooded, and dried up again about 15 times, as a result of global changes in climate: Cool climates tend to suck water up to the poles where it is stored as ice in glaciers, Lyle said. Each time the sea dried up, hundreds of feet of salts settled, later to be covered by muds. Eventually, under the weight of overlying deposits, the salts hardened and the mud turned to shale rock through a process called lithification, Lyle said.

Today, the mine's product is distributed throughout the Midwest and Northeast as road salt to help melt ice during winter months. Some abandoned mined-out areas have also been leased by a company called Underground Vaults and Storage, which offers its clients a secure and naturally climate-controlled environment to store valuable items, including a number of original Hollywood movies, according to the Strataca website.

Aside from the adventure component of the Salt Safari, Ferrell says that the museum aims to provide a compelling educational experience for the thousands of school students that visit each year, some of whom get the unique chance to spend a night in the mine.

Follow Laura Poppick on Twitter. Follow OurAmazingPlanet @OAPlanet, Facebook and Google+. Original article at LiveScience's OurAmazingPlanet.

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Tuesday, Dec. 10, 2013

In the snow, Philadelphia Eagles' Nick Foles cannot hang onto the ball during the first half of an NFL football game against the Detroit Lions, Sunday, Dec. 8, 2013, in Philadelphia. (AP Photo/Michael Perez)

Philadelphia International Airport received more snow (8.6 inches) from a single storm this past Sunday than it did all of last winter, when 8.3 inches fell.

Mother nature pulled out all the stops with heavy snow in a narrow zone centered near the Mason-Dixon Line Sunday.

The heavy snow quickly covered roadways, caused flight delays and cancellations, and contributed to many accidents.

The mechanics and variables behind the snow debacle are complex and numerous. A simple explanation is offered in this story.

According to Brian Wimer, AccuWeather winter weather expert, "For starters, a layer of fresh cold air moved in near the surface Saturday night over the mid-Atlantic and shortly thereafter a weak storm moved northeastward into that fresh cold air."

While the storm was weak, there was plenty of warm, moist air to the south waiting to be tapped.

"The weak storm allowed a warm front to set up several thousand feet above the ground which caused the air to rapidly rise and cool in an unusually narrow zone rather than be spread out over hundreds of square miles," Wimer said.

The band of heavy snow focused from parts of West Virginia to northern Virginia, northern Maryland, southern Pennsylvania, northern Delaware and southern New Jersey, including the Wilmington, Del., and Philadelphia metro areas. At times, the snow fell at the rate of 1 to 3 inches per hour.

As a result, many areas exceeded their original prediction of snow in a little over an hour. The liquid amount from the snow around Philadelphia was a factor of 20 lower, so that 1 inch of snow was only about 0.05 of an inch of water or rain.

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The band of snow could have just as easily set up farther south or north compared to where it did. Instead, it occurred in the vicinity of the Mason-Dixon Line.

According to AccuWeather.com Expert Senior Meteorologist Henry Margusity, "Horizontal winds were very light from around 5,000 to 10,000 feet up, near where the snowflakes were rapidly forming and growing most vigorously."

These light winds allowed the snowflakes to become very large and not be blown apart.

There are probably a couple of dozen of potential events similar to this past Sunday but in reality they only occur a handful of times over nation during a typical winter. Figuring out exactly where they will first set up and expand to prior to their occurrence is very challenging.

Another storm will affect part of the Northeast Tuesday. For many areas along the I-95 corridor, there may be enough to shovel and plow.

Most areas will receive between 1 and 3 inches of snow from the new storm Tuesday, spread out over a six- to eight-hour period. A narrow swath of 3 to 6 inches of snow will fall, including in some of the major I-95 cities.

PHOTOS ON SKYE: Icy Storm Hits US, Affecting Many States

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Tuesday, Dec. 10, 2013

Jim Cline clears a path for Christmas tree shoppers following a winter storm Friday, Dec. 6, 2013, in Indianapolis. (AP Photo/Darron Cummings)

Yet another blast of Arctic air will roll southeastward this week over the Midwest and will reach the Northeast.

The air will be the coldest of the season so far from Minneapolis to Chicago, Cincinnati, Detroit, Pittsburgh, Washington, D.C., Philadelphia, New York City and Boston.

The Arctic blast will be accompanied by stiff breezes and gusty winds, which will produce RealFeel(R) temperatures well below zero over the northern Plains and much of the Midwest and near zero in parts of the I-95 region.

The worst of the cold will reach the Upper Midwest Wednesday, the Ohio Valley and eastern Great Lakes Wednesday night and the Atlantic Seaboard Thursday into Thursday night.

The action of frigid air passing over the open waters of the Great Lakes will set up bands of heavy lake-effect snow, that could unload 1 to 2 feet of accumulation and produce whiteouts in some locations of upstate New York, northwestern Pennsylvania, northwestern Indiana and Michigan.

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A bit of snow can fall over the Midwest away from lake-effect areas as a weak Alberta Clipper storm rides along the leading edge of the Arctic air. Along the East Coast, the air will follow a couple of days behind a storm bringing accumulating snow Tuesday.

AccuWeather.com will have more information on the new Arctic outbreak and lake-effect snow as the week progresses.

Off-the-Charts Hottest and Coldest Places on Earth

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Off-the-Charts Hottest and Coldest Places on Earth

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The green lightning revealed an electrical dance normally hidden inside thunderclouds, Arthur Few, an atmospheric scientist at Rice University in Houston, said. "It probably occurs in all thunderstorms, but you never see it," Few said. "Because of the structure of charges in a volcano cloud, it's on the outside of the cloud."

Two spectacular photographs, snapped when Chaiten erupted in May 2008, recently caught Few's eye when he was investigating volcanic lighting. The volcano looms over the Andes about 800 miles (1,285 kilometers) south of Santiago, Chile, and erupted on May 2 of that year after lying dormant for hundreds of years. A retired professor, Few said he was driven to explain the phenomenon simply out of curiosity.

"I asked myself, 'My goodness, where does this come from and why don't we see this in lightning storms?'" he said.

Few thinks that the volcanic green lightning strikes are what scientists call "streamers" — channels of positive charge surging from the ground to the atmosphere.

In thunderstorms, these positively charged zones hide inside the clouds, carried on ice crystals, Few said. When the channels connect with clouds of negatively charged particles, lightning results. But volcanic ash reveals the streamers because ash particles swirl on the cloud's surface.

"We rarely see that positive streamer because it's inside the cloud, but it is revealed when we look at a volcanic cloud," Few said.

The green color comes from electrically excited oxygen atoms, similar to the phenomenon that produces the Earth's green aurora, he said. "It's basically the same physics," Few said.

Email Becky Oskin or follow her @beckyoskin. Follow us OurAmazingPlanet @OAPlanet, Facebook and Google+. Original article at LiveScience's OurAmazingPlanet.

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Wednesday, Dec. 11, 2013

Commuters wait on a train during a winter snowstorm Tuesday, Dec. 10, 2013, in Philadelphia. (AP Photo/Matt Rourke)

The punches just keep on coming from Old Man Winter with a new storm poised to impact parts of the South, Midwest and Northeast this weekend, threatening to bring travel delays and disruptions to outdoor activities.

While this will be a warmer storm for many areas from Texas and Arkansas to the I-95 corridor of the mid-Atlantic, compared to recent storms, it will bring snow or a wintry mix for a time in some locations and an an all-out snowstorm to areas farther north and west.

Snow is forecast to fall during part of the storm from Louisville, Ky., and Cincinnati to New York City and Boston.

The storm will affect the Central states Friday night into Saturday and much of the East Saturday into Sunday.

A stripe of heavy snow is most likely to fall over parts of northern Indiana, Ohio and northwestern Pennsylvania, upstate New York, northern New England and neighboring Canada.

Cities that could be hit with an all-out snowstorm include Cleveland, Syracuse, N.Y., and Burlington, Vt.

Most cities in the I-95 corridor of the Northeast will have a brief period of snow or a wintry mix at the onset, followed by rain at the height of the storm.

There is a chance that a wintry mix will move into Philadelphia Saturday afternoon before the conclusion of the Army-Navy Classic. A change to plain rain is forecast in Washington, D.C., Philadelphia, New York City and Boston. However, it could snow hard prior to a change to rain in part of the coastal Northeast, raising concerns for a period of slippery travel.

According to AccuWeather.com expert senior meteorologist Bernie Rayno, "For many areas in the Midwest and Northeast, this will be the third snowfall or wintry mix in a week counting the storm last weekend and the storm Monday night and Tuesday."

Some cities in the mid-Atlantic have already received more snow this winter, compared to all of last winter, including Philadelphia and Wilmington, Del.

The storms are creating major headaches for travelers and have states, cities and townships going through a great deal of ice melting compounds and spending a sizable amount of the winter budget early in the season.

In the South, enough rain can fall in some locations to cause flooding in urban and poor drainage areas. Rain and low ceilings could impact flights at Atlanta and Charlotte.

The storm will come together over the Deep South Friday and head toward a cold high pressure system moving across the Northeast.

"The storm will be preceded by the coldest air of the season so far in parts of the Midwest and Northeast," Rayno said, "The storm itself will attack the cold air, removing much of it, but squeezing out heavy precipitation in the process."

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In the wake of the storm this weekend, a mixture of Arctic and Pacific air is forecast to come in, so it may not feel quite as cold as recent days from the Midwest to the East and part of the South.

"The milder air starting next week will allow a break from the wintry precipitation in some areas hit hard, but not everywhere." According to AccuWeather.com long-range expert Jack Boston, "Just enough cold air will linger in the northern tier states to allow more storms with snow and wintry mix as the the month progresses."

PHOTOS ON SKYE: Icy Storm Hits US, Affecting Many States

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NASA's Juno spacecraft captured an amazing "starship-like view" of Earth and the moon as it made a speedy fly-by past our planet on its way to Jupiter in October.

"If Captain Kirk of the USS Enterprise said, 'Take us home, Scotty,' this is what the crew would see," Scott Bolton, the principal investigator for Juno at the Southwest Research Institute, said in a statement from NASA. "In the movie, you ride aboard Juno as it approaches Earth and then soars off into the blackness of space. No previous view of our world has ever captured the heavenly waltz of Earth and moon."

NASA unveiled the video of Earth and the moon by Juno Tuesday (Dec. 10) during the annual meeting of the American Geophysical Union in San Francisco. The low-resolution video shows the Earth spinning and growing larger in the frame as Jupiter-bound Juno makes its closest approach during the Oct. 9 Earth flyby. The images were captured using four special cameras aboard Juno that are designed to track faint stars. [See more iconic photos of Earth from space]

Earth and the moon first came into Juno's view when the spacecraft was about 600,000 miles (966,000 kilometers) away, NASA officials said. Since Juno itself was spinning, the images had to be taken from the same Earth-facing angle each time.

"Everything we humans are and everything we do is represented in that view," John Jørgensen of the Danish Technical University, said in a statement.

The Juno spacecraft launched on Aug. 5, 2011, riding an Atlas 5 rocket into space from a pad at the Cape Canaveral Air Force Station in Florida. The spacecraft only had enough power to reach the asteroid belt before the sun's gravity pulled it back toward the inner solar system. As such, mission planners had to chart a circuitous route for Juno to get it to its destination.

The spacecraft flew past Earth two months ago as a "gravity assist" to increase the spacecraft's velocity relative to the sun. This slingshot around our planet boosted Juno from a speed of 78,000 mph (126,000 km/h) relative to the sun to a speed of 87,000 mph (140,000 km/h).

As it zipped past the planet, the spacecraft's JunoCam also captured a stunning picture of Earth with a higher resolution than the newly released images.

Additionally, ham radio operators from around the world had a chance to say "HI" to Juno during the flyby by coordinating radio transmissions with a Morse-coded message. The radio signals were recorded by Juno's Waves instrument, which eventually will measure radio and plasma waves in Jupiter's magnetosphere, according to NASA.

Mission officials say Juno is now on course to arrive in a polar orbit around Jupiter on July 4, 2016. The spacecraft is supposed to circle the planet 33 times, using its instruments to peer beneath the dense cloud cover that hides our solar system's largest planet.

Scientists hope the $1.1 million mission will help answer longstanding questions about Jupiter - such as whether or not it has a core - and that it will shed light on the planet's origins, atmosphere and magnetosphere.

Follow Megan Gannon on Twitter and Google+. Follow us @SPACEdotcom, Facebook or Google+. Originally published on SPACE.com.

• Starship-Style Earth Fly-By From Jupiter-Bound Probe | Video
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Wednesday Dec. 11, 2013

A huge meteor hurtles to earth during the annual Geminid meteor shower on Dec. 14, 2009, in this photo taken from the Mojave Desert area near Victorville, Calif. (Wally Pacholka/Barcroft Media/Getty Images)

The Geminid meteor shower -- one of the most spectacular meteor displays of the year -- may hit its peak this weekend, but some stargazers in Arizona got a sneak preview of the celestial light show Tuesday night (Dec. 10).

A meteor exploded over Arizona, rattling windows and producing at least one loud boom, according to press reports, but the meteor explosion itself was not part of the Geminid meteor shower, a meteor expert says.

"It [the meteor explosion] was picked up by two of our meteor cameras in New Mexico as well as cameras in Arizona and the preliminary trajectory shows that it was definitely not a Geminid," NASA meteor expert Bill Cooke told reporters today. "It was moving way too slow and coming from the wrong direction." [See photos of the 2012 Geminid meteor shower]

The Geminid meteor shower -- so named for it radiant point in the constellation Gemini -- is set to peak in the overnight hours from Dec. 13 to 14. At its height, skywatchers in dark areas should be able to see anywhere from 90 to 120 meteors per hour, weather permitting, according to some forecasts.

Observers will have the best chance to see the so-called "shooting stars" after 4 a.m. local time when the waxing moon sets. Under usual circumstances, it's better to catch the Geminids a little after midnight local time, however, this year, the moon could get in the way, making the 4 a.m. hour a better bet.

Geminid meteors can be slow and bright with a yellowish hue, but sometimes the shower produces bright fireballs.

"The best thing to do to observe meteors is to lie flat on your back and look straight up," Cooke said. "You don't want to look at Gemini, you just want to look straight up and take in as much of the sky as possible because meteors can appear anywhere in the sky and the more sky you see, the better you chance of seeing a meteor."

The Geminids are created each year when Earth passes through dust left behind by the asteroid 3200 Phaethon. The shower was first documented in the 1800s when there were only 10 to 20 meteors per hour at peak, however, the intensity of the shower has increased over the years.

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Thursday, Dec. 12, 2013

A worker clears snow from a sidewalk in view of Independence Hall during a winter snowstorm Tuesday, Dec. 10, 2013, in Philadelphia. (AP Photo/Matt Rourke)

Those hoping for a white Christmas this year could be in luck, even in a few areas where Dec. 25 snowfall would normally be nothing more than wishful thinking.

As of Dec. 11, measurable snow covered 62.1 percent of the United States, compared to 31.4 percent on the date last year.

"Last year was a little bit below normal and this year is a little bit above normal, so it looks pretty dramatic in comparison to each other," AccuWeather.com expert senior meteorologist Mark Paquette said.

Overall, the current snowpack marks the most extensive coverage for the date in the past five years.

The extensive snow coverage is due largely in part to surges of Arctic air that have settled over the United States.

"Basically the flow of air has been due north with very little westerly component," Paquette said. "The Arctic air just keeps getting replenished. As long as it stays north and not west, it will keep coming down in waves."

The cold air allowed early wintry precipitation to occur last week in some unusual areas, including parts of Texas, Oklahoma and Arkansas. The swath eventually stretched farther east into the mid-Atlantic.

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The storm, which began early on Dec. 5, is responsible for a significant percentage of the nation's coverage.

Over the course of five days, from Dec. 5-9, the snow cover increased by 29 percent, from 37.9 percent to 66.9 percent.

The percentage of U.S. snow cover for Dec. 11, 2013, trumps even last year's coverage of 51.1 percent for Christmas Day, two weeks farther into the season than the current date.

Another storm arriving this weekend will bring snow to the Ohio Valley and Northeast, bolstering the region's snowpack. Meanwhile, snow, rain or a wintry mix is forecast along the I-95 corridor of the mid-Atlantic.

Despite this, a sudden warmup at the start of the Christmas week could threaten the odds of a white Christmas for portions of the South and East.

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