Category Archives: Weather & Sky

On Vortex Street

Clouds on the lee side of Guadalupe Island, Mexico, 24 May 2017 (image from NASA’s Landsat satellite)

What do these photos and video have in common?

Smokestacks at Proserpine Mill, Jan 2012 (photo from Wikimedia Commons)

humming sound of wind in the wires (turn up speakers)

Answer: All three indicate the presence of — or potential for — a von Kármán vortex street.

When you’re in the neighborhood, this street is a fluid dynamic place. Learn more in this vintage article as we go Walking Down Vortex Street. (click the link)

(photos NASA and Wikimedia Commons; click on the captions to see the originals. video by Megan Lewis on YouTube)

No Winter Fun

Snow shovel riding, Slovakia 1959 (photo from Wikimedia Commons)

Now that climate change has really settled in there are loads of free fun winter activities that we can’t do in Pittsburgh. I was reminded of this when I heard that the Beaver County Snow Shovel Riding Championship was postponed last Saturday. Last year it was eventually canceled. As the Beaver County Times wrote last month:

The Beaver County Snow Shovel Riding Championship returns in 2020. That comes with the major assumption that sufficient snow rests on the 165-foot hill at Old Economy Park, just off Route 989 in Economy, on Jan. 11 or the makeup date of Jan. 18.

Beaver County Times, Let it snow, if shovel riding championship is to return

Last Saturday, 11 January 2020, was so hot that it broke a 130-year record. At Pittsburgh International Airport, nine miles from that Beaver County hillside, it was 71 degrees F. Of course there was no snow.

Other winter fun we’re missing includes building snowmen, making snow angels, and cross country skiing. These still might happen for a day or two if we get one big snowfall.

Building a snowman at Lafayette Park (photo from Wikimedia Commons)
Making a snow angel (photo from Wikimedia Commons)
Cross country skiing, Aroostook NWR, 2012 (photo from Wikimedia Commons)

But some winter fun is just plain dangerous in today’s world. Ice fishermen used to count on our frozen lakes but these days the ice is missing or very thin. Unsafe!

Ice fishing at Price Gallitzin State Park, PA, 2010 (photo from Wikimedia Commons)

To emphasize this dilemma, the Great Lakes were virtually ice free on January 12.

Ice coverage on Great Lakes, 12 Jan 2020 analysis (map from US National Ice Center)

No winter fun.

(photos from Wikimedia Commons; map from U.S. National Ice Center; click on the captions to see the originals)

What We’re Missing In Today’s Hot Weather

Macro snowflakes in frozen bubble (photo from Wikimedia Commons)

11 January 2020

Winter has a beauty all its own but we’re missing it in Pittsburgh this year. Today our high temperature will be 70oF.

Here’s some of what we’ll never see in today’s hot weather.

Hoarfrost on Hibiscus (photo by Reinhold Möller via Wikimedia Commons)
Snow on Queen Anne’s lace, 2015 (photo by Kate St. John)
Tiny snowman at Gilfillan Park, 2 Jan 2020 (photo by Kate St. John)

Pittsburgh is not alone in feeling the heat. Here’s today’s temperature forecast for the continental U.S. It looks like a Polar Vortex doesn’t it? High winds are on the way!

(photos from Wikimedia Commons and Kate St. John, map from the National Weather Service; click on the captions to see the originals)

A Hot Wet Year Ahead

If you live in Pittsburgh — or Alaska — you can expect a hot wet year in 2020.

In late December National Weather Service Climate Prediction Center published U.S. seasonal outlook maps for 2020’s temperature and precipitation, one map per quarter.

For temperature, the redder the color the more likely it will be hotter than normal. For precipitation, green means it’s likely to be wetter. Pittsburgh is high in both categories, hot and wet. So is Alaska, especially in temperature.

Watch the year heat up.

(images from the National Weather Service Climate Prediction Center, Monthly & Seasonal Outlook Maps)

To See Again The Stars

Milky Way at Tenerife (photo by Carl Jones on Flickr, Creative Commons license)

At the end of The Inferno, set in the year 1300, Dante and his guide Virgil escape from Hell climbing upward to reach the Earth. They’ve almost emerged when Dante looks through the opening ahead and sees the heavens above.

we climbed up, he first and I behind him,
far enough to see, through a round opening,
a few of those fair things the heavens bear.
Then we came forth, to see again the stars.

The Inferno by Dante Alighieri, translation by Robert & Jean Hollander

The heavens are still wondrous but most of us miss it. So much electric light floods the sky that we cannot see the stars. No Milky Way (above), no meteor showers (below).

Timelapse composite, Perseid meteor shower, 13 Aug 2015 (photo from Wikimedia Commons)

This seven minute video gives a glimpse of what we’re missing.

To see the stars as Dante saw them we have to visit remote locations where the sky is dark. Click on the Milky Way photo at Tenerife (top) to see the sky in full screen splendor.

“Then we came forth, to see again the stars.”

p.s. This week we learned of an unexpected threat to viewing the stars: Thousands of tiny new satellites will obscure and confuse the astronomers’ view.

(photos from Carl Jones on Flickr and Wikimedia Commons; click on the captions to see the originals. video by Peaceful Cuisine on YouTube)

Ball Ice On The Beach

Ice balls at Stroomi Beach, Tallinn, Estonia, Dec 2014 (photo form Wikimedia Commons)

On rare occasions, winter weather and the sea conspire to make ice balls that stack on the beach when they roll ashore. This ball ice, about the size of softballs, covered Stroomi Beach at the Baltic Sea in Estonia in December 2014.

Ball ice is so rare that it made the news last month in Alaska and Finland. Similar to hail, it forms in bays where the water is relatively calm and just cold enough to make ice. A “seed” of ice or grit starts the process, then wind and gentle waves keep turning the floating ball as it grows.

Sometimes two cool things happen at once. In this tweet from NWS APRFC, a field of ice balls in Alaska acquired pointy hats when snow or rime accumulated on one side.

The prettiest ball ice by far were the thousands of white balls covering a beach on Hailuoto Island, Finland in early November. Ranging in size from golf balls to soccer balls, they made international news in photos by Risto Matilla. Island resident Ritva Rundgren filmed them for her Mrs. Santa Claus Finland blog.

Read more about Finland’s ice eggs and see a video of ice balls at Lake Michigan in this article from ScienceAlert.

(photo from Wikimedia Commons; click on the caption to see the original. Video embedded from Mrs. Santa Claus Finland)

Winter Solstice

Winter solstice 2012: Noon sunrise on the Bering Sea (photo by Bering Land Bridge National Preserve on Flickr)

Winter Solstice: 21 December 2019

Today the sun will pause at 11:19pm Eastern Time and begin to move north again — or so it will seem to us earthbound humans.

The far north will be dark but not inky black everywhere. At Kotzebue, Alaska, 26 miles north of the Arctic Circle, the sun will rise at 12:56pm and set 1 hour and 43 minutes later, similar to the solstice photo above, taken at Bering Land Bridge NP. Kotzebue is the furthest north I’ve ever been though I didn’t get off the plane..

Scene from the plane at Kotzebue, Alaska on the day before the summer solstice, 2019 (photo by Kate St. John)

Here in the Lower 48 we’ll have lingering sunsets …

Sunset at Kelly Brook, Spruce, Wisconsin around the winter solstice (photo by Alan Wolf via Flickr Creative Commons license)

… and the days will get longer tomorrow.

Soon the birds will think about spring for reasons described in this vintage article: In Response To Daylight.

(photos by Bering Land Bridge National Preserve, Kate St. John, and Alan Wolf on Flickr, Creative Commons licenses; click on the captions to see the originals)

Penitent Snow

On top of the world at Chajnantor Plateau, Chile. Penitente in the foreground (cropped photo from Wikimedia Commons)

If you don’t like snow, here’s some that you’ll never see in Pittsburgh.

These snow formations, called penitente, are found at elevations above 13,000 feet in the Dry Andes of Chile and Argentina. They form when the snow vaporizes — directly from solid to gas — in the cold dry wind. A feedback loop of sublimation and ablation creates snow peaks as tall as 16 feet.

Penitentes at the southern end of the Chajnantor plain (photo from Wikimedia Commons)

Penitente are named for their resemblance to kneeling penitents or the hoods worn during Spanish Holy Week. They even resemble this statue of Saint Bernadette at the grotto at Nevers.

Grotto at Nevers, France (photo from Wikimedia Commons)

Sometimes a snow field will reach across the road …

Snow field of penitentes (photo from Wikimedia Commons)

… so people get out of their cars to look at it. This one is at Agua Negra Pass on the border of Chile and Argentina, elevation 15,682 ft.

Penitentes at Paso de Agua Negra, Argentina, elev. 15,680 ft (photo from Wikimedia Commons)

The “penitent” snow creates an otherworldly scene. Click on the photo below for a panoramic view at night.

Planetary Analogue: Penitente on a starry night in the Atacama desert (photo from Wikimedia Commons)

(photos from Wikimedia Commons; click on the captions to see the originals)

Danger! Space Junk

Last month I wrote about the damage that bad space weather can do to satellites, the electric grid, radio and TV transmissions, and GPS navigation. Though space weather can kill a satellite(*) bad weather is temporary. Not so with space junk.

Since 1957 when the Space Age began, our unused equipment has created a garbage patch in outer space. Over the years we’ve launched 5,000+ satellites though only 1,300 are operational today. There’s a lot of junk up there that’s out of control (can’t be navigated anymore) and potentially explosive.

screenshot of space junk explosion from PBS Be Smart

Even if it can’t explode, space junk is dangerous to active satellites because it travels so fast. In Low Earth Orbit, where the International Space Station lives, everything travels at 17,500 miles per hour (28,000 km/hour). A crash at that speed, even with a tiny object, can destroy a satellite. When a satellite dies something electronic fails here on Earth.

Meanwhile we’re launching more satellites every year at a faster pace than before. At the end of 2018 it had taken a decade to launch 1,000 CubeSat nano-satellites, only four-inches across, but there are plans to add 1,000 more by 2021. Outer space is so crowded that NASA and the European Space Agency (ESA) work every day to steer satellites away from dangerous space debris.

The 2016 video above describes space junk and how we’ve coped with it so far. Note that it doesn’t talk about CubeSats because the video predates those plans.

ESA’s 2017 video below describes the problem in technical terms with dramatic background music. I’ve cued the video to start at Low Earth Orbit. Watch for two minutes (beyond the first fade-to-black) and you’ll see lots of collisions.

Yow! It’s crowded up there.

(videos from PBS It’s OK To Be Smart and the European Space Agency (ESA) on YouTube)

(*) Space weather killed Telstar 401 in 1997.

Angry Storm On Saturn

Saturn’s north polar vortex storm (photo from Wikimedia Commons)

This month a KDKA viewer saw unusual clouds like breaking waves in the sky as he was traveling on the Turnpike to Philadelphia.

Our planet isn’t the only one that has these clouds. This photo of Saturn’s north polar vortex shows Kelvin-Helmholtz clouds on the spinning edge. Photographed by the Cassini spacecraft in April 2013 and colorized by NASA, this image is called The Rose but is actually a violent, relentless storm. And it’s big!

According to the Cassini Mission at NASA, “Measurements have sized the eye at a staggering 1,250 miles (2,000 kilometers) across with cloud speeds as fast as 330 miles per hour (150 meters per second).”

Our own polar vortex is mild by comparison.

(photo from NASA via Wikimedia Commons; click on the caption to see the original)