Tag: weather

Green Flash: Sunset Phenomenon

green-flash

A green flash, which occurs more commonly at sunset but can also occur at sunrise is a phenomenon in which part of the sun can be observed suddenly and briefly changing color.

It usually lasts only a second or two which is why it is referred a flash as the sun changes from red or orange at sunset, for example.

The green flash is viewable because refraction bends the light of the sun. The atmosphere acts as a weak prism, which separates light into various colors.




When the sun’s disk is fully visible above the horizon, the different colors of light rays overlap to an extent where each individual color can’t be seen by the naked eye.

As the sun sinks into the Pacific, its last light seems to glow green. This “green flash,” caused by light refracting in the atmosphere, is rarely seen.

But Nigella Hillgarth, the director of the Birch Aquarium at the Scripps Institution of Oceanography in San Diego, got lucky one night.

green-flash

I often work late and have developed the habit of taking photos of the incredible sunsets over the Pacific from the Aquarium,” Hillgarth said.

One evening, I was snapping away and caught the green flash as it appeared. I was hoping for a green flash, but was very excited when one actually happened and I caught it!

When the sun starts to dip below the horizon the colors of the spectrum disappear one at a time, starting with those with the longest wavelengths to those with the shortest. At sunrise, the process is reversed, and a green flash may occur as the top of the sun peeks above the horizon.

green-flash

It is a primarily a green flash because more green light gets through and therefore is more clearly seen.

Sometimes, when the air is especially clear, enough of the blue or violet light rays make it through the atmosphere, causing a blue flash to be visible. However, green is the most common hue reported and captured in photos.

Most green flashes fall into two categories: inferior mirage flashes and mock mirage flashes.

green-flash

Inferior mirage flashes, which accounts for about two-thirds of all green flash sightings, are oval and flat and occur close to sea level and when the surface is warmer than the air above.

Mock mirage flashes occur higher up in the sky and when conditions on the surface are colder than the air above. The flashes appear to be thin, pointy strips being sliced from the sun.

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The Weirdest Weather Events of 2018 So Far

 

We’ve already seen our share of winter storms, severe weather, cold outbreaks, flooding and droughts so far in 2018. But there are some weather events every year that are downright strange, and this year is no exception.

The events we consider strange are weather phenomena happening repeatedly in one place, in a place where you wouldn’t think they would occur or during an unusual time of year.

Some are phenomena you may not find in a Weather 101 textbook.




Freezing Rain in Florida

Just after New Year’s Day, Winter Storm Grayson blanketed Tallahassee, Florida, with its first measurable snow since 1989, and the first January such occurrence, there, in records dating to 1885.

That’s eye-catching enough.  What was even more bizarre was seeing an ice accumulation map involving the Sunshine State.

Up to a quarter inch of ice accumulation was measured in Lake City, and light icing on elevated surfaces was reported as far south as Levy County.

A Horseshoe Cloud

A horseshoe cloud was captured over Battle Mountain, Nevada on Mar. 8, 2018.

While the nor’easter parade was hammering the East Coast, a bizarre cloud was captured in video over Nevada in early March.

As meteorologist Jonathan Belles explained, this rare horseshoe vortex is fleeting, lasting only minutes, when a relatively flat cloud moves over a column of rising air, which also gives the cloud some spin.

A State Record Hailstone

The hailstone that was saved from a March 19, 2018, hailstorm near Cullman, Alabama, later to be found to set a state record.

Alabama’s notorious history of severe weather, particularly tornadoes, is well documented.  On March 19, however, it was a hailstone that captured meteorologists’ attention.

One softball-size hailstone near Cullman, Alabama, was found to set a new state record, more than 5 inches in diameter.

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How Far Away Is A Lightning?

Next time you’re stuck in a thunderstorm, try this easy way to calculate how far away you are from lightning strikes.

Just count the number of seconds that pass between a flash of lightning and the crack of thunder that follows it, then divide that number by five.

The resulting number will tell you how many miles away you are from where lightning just struck.




Five seconds, for example, indicates the lightning struck 1 mile away, and a 10-second gap means the lightning was 2 miles away.

This technique is called the “flash-to-bang” method, and it can keep you safe during rainy summer weather.

The National Weather Service recommends taking cover if the time between the lightning flash and the rumble of thunder is 30 seconds or less, which indicates the lightning is about 6 miles away or closer.

This method is based on the fact that light travels much faster than sound through the atmosphere: Light travels at 186,291 miles per second (299,800 km/s), whereas the speed of sound is only about 1,088 feet per second (332 meters per second), depending on air temperature.

For metric-system conversions, follow this method: Sound travels at about 340 m/s, so multiply the number of seconds you counted by 340, and you’ll know how many meters away lightning struck.

A three-second count, then, would place the lightning strike about 1,020 m away, or roughly 1 km.

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Watch Lightning Seen From Space

Astronauts were treated to a striking sight when they spotted a lightning storm from space.

These stunning images caught an electrical storm in full flow almost 250 miles above the earth while the space men were orbiting at 17,895 mph in the International Space Station.

The pictures show the swirling clouds and multiple lightning strikes as the eye of the storm moves across land, thought to be Iran.




The flashes were spotted by the European Space Agency’s Nightpod camera, which astronauts set up to take crystal-clear images which have only now been released after being taken in 2012.

Despite the distance from the planet and the speed involved, the high-tech camera is specially adapted to keep the pictures in focus to avoid blurring.

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What If The Moon Disappeared Tomorrow?

Ah, yes, the moon. To it, over it, shooting for it. Blue, green. Pies, faces, shines, lighting. And I haven’t even gotten to all the Luna-based concepts. Earth’s moon plays a significant role in our culture, language and thoughts.

But does it … you know … matter? If it disappeared in the blink of an eye tomorrow (and for discussion’s sake let’s assume it does so nonviolently), would we even notice? Would we even care?

Well, it depends ….

Do you like tides?

Gravity — at least the Newtonian kind — is pretty straightforward: The closer you are to something, the stronger its pull of gravity.

So stuff that’s closer to the moon gets a stronger gravitational tug, and stuff that’s farther away gets a weaker one. Easy-peasey.

When looking at the effects of the moon on the Earth, you can essentially boil it down to three parts: The Earth itself, the ocean-close-to-the-moon and the ocean-far-from-the-moon.

On any given day, the ocean closest to the moon gets a bonus gravitational pull, so it rises up slightly, reaching out in watery embrace to what it can never reach.




And since the ocean is so big, all the water from one horizon pushes up against water from the other, resulting in a fantastic tidal bulge.

OK, tide on one side of our planet, done. But what about the other?

The solid rocky bits of the Earth are closer to the moon than the ocean on the far side, so the Earth too gets a little more snuggly with the moon, leaving the far-side ocean behind.

Result? Tides on the far side. From the perspective of someone standing on Earth, it looks like that ocean is rising up, but really it just doesn’t get to join the party. And there you have it: two tides on opposite sides of the Earth.

If the moon disappeared, we wouldn’t be totally out of tidal luck; the sun also stretches and squeezes the Earth, so our surfing opportunities wouldn’t be completely eliminated.

Do you like 24 hours in a day?

The Earth used to spin on its axis faster than it does today. As in, way faster. After the hypothetical giant impact that led to the formation of the moon, the Earth’s day was as short as 6 hours. How did it get to a leisurely 24?

That’s right, it was the moon! The moon makes some pretty nice tides, but the Earth is also spinning on its axis. That spinning physically drags the tidal bulges around the planet.

So instead of the tides appearing directly beneath the moon, they’re slightly ahead of it, orbitally speaking.

So you’ve got a big lump of extra ocean water in a place where it’s not supposed to be. Since gravity is a two-way street, that lump pulls on the moon.

Like tugging a reluctant dog on a leash, that tidal bulge yanks on the moon bit by bit, accelerating it into ever-higher orbits.

By the way, the moon is slowly getting farther away from Earth.

And that energy to accelerate the moon has to come from somewhere, and that somewhere is the Earth itself: Day by day, millennium by millennium, the Earth slows down, converting its rotational energy into the moon’s orbital energy.

If you took away the moon, itꞌs not like this process would reverse, but it wouldn’t keep going. That might or might not be a good thing, depending on how much you like the length of your workday.

Do you like seasons?

The Earth’s axis is tilted, and that tilt can change with time. No biggie, all the planets do it; it’s fun. But what’snot fun is when the tilt changes rapidly.

What would happen if Antarctica pointed straight at the sun for 24 hours a day, plunging North America and Europe into permanent darkness?

And then a few hundred thousand years later it flipped over? We take the long-term regularity of our seasons for granted, and we might have the moon to thank for it.

Those kinds of crazy wild swings in the axial tilt are due to resonances, or unlucky interactions with distant objects in the solar system.

For instance, letꞌs say that one day in its orbit the Earth’s axis just happens to point away from the sun, and Jupiter is hanging out in that direction at the same time.

And let’s say that happens again … and again … and again. Every time Earth’s axis and Jupiter line up, it gets a super-tiny gravitational pull. At first it’s nothing.

But over millions of years it can add up. Before you know it, the accumulation of tugs has flipped the Earth over like a pancake.

What might stabilize this is the moon: it’s really, really big, and orbits us pretty fast. All that angular momentum prevents the other planets from playing any axial shenanigans.

Or not. The moon may actually be hurting us in the long term, since it’s slowing us down, which makes us more susceptible to the intrigues of the outer planets.

But that’s a billion-year problem anyway, and if the moon disappeared tomorrow, our seasons would still be seasonal for a really long time.

So, besides the tides, would we notice a disappeared moon? Well, yes, because it’s really big and bright, and there’d be nothing to howl at anymore. But would it affect us? Not really. So as for the moon … I’m over it!

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Parts Of The Arctic Spiked To 45 Degrees Above Normal

In December, a team of U.S. government scientists released a “report card” on the Arctic. Their top conclusion was pithy, comprehensive, and bleak. The Arctic, they said, “shows no sign of returning to [the] reliably frozen region of recent past decades.”

Now, it’s almost like the environment is trying to prove them right.

Though the sun hasn’t shone on the central Arctic for more than four months, the region is currently gripped by historic, record-breaking warmth.




On Sunday, the temperature at the North Pole rose to about the melting point, and parts of the Arctic were more than 50 degrees Fahrenheit warmer than normal.

A handful of Arctic scientists spent the weekend on Twitter, trying to put the episode into context:

To understand how strange the recent Arctic weather is, it’s worth looking at a place called Cape Morris Jesup.

Cape Morris Jesup is a barren and uninhabited promontory above the Arctic Ocean. Just 450 miles from the North Pole, it is Greenland’s northernmost point.

The sun hasn’t shone on Cape Morris Jesup since October 11. These should be among the coldest weeks of the year for the cape.

But over the weekend, the weather station there recorded an air temperature of 43 degrees Fahrenheit, more than 50 degrees above normal for this time of year.

The weird warmth was not limited to that one spot. Station Nord, a scientific research station in Greenland nearly 200 miles to the southeast, recorded temperatures of about 36.5 degrees Fahrenheit this weekend.

The Climate Reanalyzer, a tool from the University of Maine, uses data from the U.S. weather model to show how far temperatures have deviated from historic norms. On February 26, 2018, the Arctic was almost 5.4 degrees Celsius (about 10 degrees Fahrenheit) warmer than normal, while much of Europe was almost 10 degrees Celsius colder than normal.

These kinds of on-the-ground observations aren’t available for the North Pole.

But by combing satellite observations and other temperature data, the top U.S. forecast model estimated that temperatures at the North Pole rose as high as 35 degrees Fahrenheit.

At this time of year, sea ice should still be growing and expanding. But recent satellite observations have shown that two large gaps have somehow opened up in the ice. The first is in the Chukchi Sea, near Russia.

How rare is this kind of Arctic warmth? Climate scientists say they have seen events similar to this one happen before, but that the size and intensity of the warmth made it really notable.

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Shocking Video Shows 12-Year-Old Boy Nearly Struck By Lightning

A mother in Argentina captured the moment her 12-year-old son was almost hit by lightning while playing in the rain.

The unnamed boy is seen in the video playing with his umbrella under a downspout before walking out into a grassy area near his home.




Just then, a powerful bolt of lightning strikes just feet from where the boy is standing.

The boy’s mother says her son survived the incident, according to multiple reports.

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The Physics Behind Hitting A Home Run

On Monday night, some of Major League Baseball’s best sluggers will square off in the sport’s biggest annual display of brute strength: the home run derby.

Each batter has seven “outs” to hit as many balls as possible out of San Diego’s Petco Park.

To most fans, it’s just a fun spectacle. But to Alan Nathan, home-run hitting is a physics problem.

Given the distance between home plate and the outfield wall, what combination of ball speed, bat angle and external factors will send the ball out of the park?

By day, Nathan is a professor emeritus at the University of Illinois at Urbana-Champaign, working to elucidate the structure and interactions of subatomic particles.

But the rest of the time, he’s watching baseball with an eye for the underlying physics of the sport. He’s even written several peer-reviewed papers on the subject, which are all available on his website.

At the most basic level, he said, there are just two elements to a well-hit home run: exit speed and launch angle.

If you were a freshman physics student calculating the path of a projectile, these two numbers would be all you needed to know to predict how far the ball would travel.




According to ESPN’s hit tracker, the fastest-hit home run of the season so far was a solo shot slugged by the Angels’ Mike Trout in April.

That ball was traveling 120.5 mph when it left Trout’s bat. The optimum launch angle, Nathan said, is between 25 and 30 degrees. A ball hit at a lower angle will become a line drive or a grounder; a higher angle gives you a pop-up.

These factors can balance one another. A slower ball may make it out of the park if it’s hit at the right angle; a batter can make up for a bad trajectory by hitting the ball super fast.

But astute students of baseball science should take other factors into account.

Those first four all boil down to the same thing: air density. The less dense the air is, the less resistance the ball will encounter as it soars through the stadium.

The thin air at high elevations helps balls travel farther — that’s part of how Denver’s Coors Field, which sits at an MLB-high of 5,200 feet above sea level, got its reputation as a pitcher’s nightmare.

On the other hand, humidity in the stadium can help a home-run ball — if only ever so slightly — by making the air less dense.

Air temperature also plays a part, Nathan said. A 1995 study found that fly balls travel a few feet farther for every 10 degree increase in temperature.

The average fly ball distance in above-90-degree heat was 320 feet; on sub-50-degree days, that distance fell to 304 feet.

But the effect of air density pales in comparison to that of wind.

How far a ball flies also depends on the ball itself.

The stitches on a baseball help it travel farther by reducing drag, but only to a degree — high, loose seams, like those of the repeatedly reused baseballs of the “dead ball” era, will slow it down again.

Then there’s how you hit the ball. Side spin — which happens when the batter is out in front of the ball or just a little bit late — can cause a line drive to curve foul.

But a small amount of back spin gives the ball lift, allowing it to seemingly defy gravity for slightly longer than it otherwise would.

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NASA To ‘Revolutionize’ Weather Forecasting With Launch Of Billion Dollar Satellite

A billion-dollar satellite that is promised to revolutionise weather forecasting and in turn help save lives has been successfully launched by NASA.

The new GOES-R satellite will provide higher resolution images and more frequent updates of weather patterns, improving forecasts and weather warnings and in turn help save lives by giving people more time to evacuate ahead of a hurricane or storm.

Thousands of people travelled to Cape Canaveral in Florida for the launch, including TV meteorologists and space programme workers.

NBC meteorologist Al Roker said: “What’s so exciting is that we’re going to be getting more data, more often, much more detailed, higher resolution.”

“In terms of tracking tornadoes, he said that “if we can give people another 10, 15, 20 minutes, we’re talking about lives being saved.




The launch of the GOES-R represents a major step forward in terms of our ability to provide more timely and accurate information that is critical for life-saving weather forecasts and warnings,” said Thomas Zurbuchen, associate administrator for Nasa’s Science Mission Directorate.

It has been built as part of an $11bn (£8.9bn) programme and will help to monitor hurricanes, tornadoes, flooding, volcanic ash clouds, wildfires and lightning storms in America.

The satellite itself, which has been launched by Nasa for the National Oceanic and Atmostpheric Administration (NOAA), has been valued at £1bn.

Sandra Cauffman, deputy director of Earth Sciences at Nasa, called the new satellite a “quantum leap” that will “truly revolutionise forecasting”.

In addition to providing vastly improved forecasting, the satellite’s information will also help pilots avoid bad weather and rocket scientists to know when to call off a launch.

It will also be part of the international Search and Rescue Satellite Aided Tracking (SARSAT) system, which can detect distress signals from emergency beacons.

The billion-dollar satellite will reach its designated 22,300-mile-high equatorial orbit in two weeks’ time and, after a series of checks, will become operational within a year.

It is the first to be launched since 2010 and will outstrip its predecessors, sending full images of the western hemisphere every 15 minutes, instead of the current 30-minute time frame, and will send images of the continental United States every five minutes, with images of specific regions updated every five seconds.

Its lightening mapper will hone in on storms that represent the greatest threats, Nasa said in a statement, while the satellite’s Advanced Baseline Imager will send scientists images of the Earth’s weather, oceans and environment.

The lightening information is kind of like going from a black and white television to a high-definition television system,” said Todd McNamara, a meteorologist with the US Air Force 45th Weather Squadron at the base.

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Ice Chunks Are Fascinating To Look At, But Can Cause Serious Flooding

Mohawk River ice jam: Giant chunks of ice washed up on the shore of the Mohawk River.

The weather has been all over the spectrum in the last few weeks.

Record-breaking frigid temperatures and wind chills kicked off 2018, followed by temperatures into the 50s and 60s last week.

Temperatures plummeted to start off this week, and central Pennsylvania woke up Wednesday to a few inches of fresh snowfall.




A gradual warmup is expected into this weekend, with highs in the 50s predicted. The upcoming warmup has meteorologists keeping an eye on what the warmer weather could mean for ice jams in rivers and streams.

It’s something we’re going to have to keep an eye on,” said Craig Evanego, a meteorologist with National Weather Service.

Evanego explained the warmer temperatures could enable ice jams to break free and move down rivers and streams.

He added that some areas in the northern part of the state are already experiencing ice jam issues on localized streams thanks to elevated water levels.

Frozen river ice: Frozen river ice melts in layers as chunks wash up on shore.

With the gradual warmup, we’ll see if things will begin to thaw and move down the (Susquehanna) river,” Evanego said.

Senior meteorologist Alex Sosnowski with AccuWeather said that thanks to the persistent cold, pretty thick layers of ice have been able to form.

Along with fluctuating temperatures, Sosnowski said river levels are a little higher, adding that another rain event is expected from Monday to Wednesday next week.

Mohawk River ice jam: Jams can cause floods, which threaten buildings near the banks.

Sosnowski explained a major risk with ice jams is that when they break free, they send a surge of water down the river, which can cause flooding in unprotected areas.

Sosnowski expected that levee systems should be able to protect against any flooding caused by ice packs, and said unprotected areas are at the most risk for flooding.

Sosnowski encouraged those who want to go out and observe ice packs to do so carefully, as they can break away and begin drifting downstream at any time.

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