Category Archives: Weather & Sky

Sunrise On The Longest Day

Summer solstice sun rises over the Heel Stone at Stonehenge, 2005 (photo from Wikimedia Commons)

20 June 2020

Today the summer solstice arrives in Pittsburgh at 5:43pm EDT giving us this year’s longest daylight of 15 hours 3 minutes and 54 seconds(*).

If you were tracking the sun’s location at sunrise you would see why “solstice” means “sun stands still” for it rises at nearly the same place for a day or two before it heads south again.

Stonehenge near Salisbury, England is the perfect place to watch this happen as the sun rises over the Heel Stone on the summer solstice.

Some of the crowd at Stonehenge sunrise, 2005 (photo from Wikimedia Commons)

Normally huge crowds gather at Stonehenge to watch this phenomenon but English Heritage has canceled the 2020 celebrations and is urging people to stay away because of COVID-19.

Fortunately we can all watch sunrise at Stonehenge via live stream on the English Heritage Facebook page. Tune in on Sunday June 21 at 4:52 am British Summer Time, which is Saturday 11:52 pm Eastern Daylight Time.

Night owls in Pittsburgh don’t have to get up early to watch sunrise on the longest day.

(*) Pittsburgh’s 20 June sunrise was at 5:49am, sunset at 8:53pm.

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

Despite The Cold, An Early Spring

Honeysuckle buds March 2019 vs Feb 2020 (photos by Kate St. John)

Except for a 10 degree cold snap in the last 24 hours, we’re having an early Spring.

So far this year temperatures in Pittsburgh have been 10-34 degrees above normal a third of the time. January 11 was 34 degrees above normal at 71 degrees F.

Honeysuckle bushes responded by leafing out. Last Monday (10 February 2020) I found open honeysuckle buds in my neighborhood. I took a similar photo last year on 11 March 2019 but it was whole month later and the buds were not as open.

According to the USA National Phenology Network, Spring is three weeks ahead of schedule in the southeastern US:

Spring leaf out has arrived in the Southeast, over three weeks earlier than a long-term average (1981-2010) in some locations. Charlottesville, VA is 24 days early, Knoxville, TN is 20 days early, and Nashville, TN is 18 days early.

Status of Spring

Here’s what it looks like on the map as of 14 February 2020.

Spring Leaf Index as of 14 Feb 2020 (animation from USA National Phenology Network)

Despite the cold, today will warm to almost 40 degrees in Pittsburgh and to 52 by Tuesday. I think we’ll still have an early Spring.

(photos by Kate St. John, map from


Moon and Jupiter reflected on Brofjorden, Sweden (photo from Wikimedia Commons)

When the moon is bright, the sky is clear, and the wind is calm the moon’s reflection makes a path on the water.

In Sweden where this photo was taken the word for the moon’s path is mångata or “moon street.”

In English we have a name for it, though the word is rarely used: Moonglade.

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

Space Junk May Collide Over Pittsburgh Tonight

Space junk collision (screenshot from PBS Be Smart video)

Wednesday, 29 January 2020:

Chances are it won’t happen but …

Tonight at around 6:39pm two defunct satellites that are still in orbit have a 1% (or less) chance of colliding 900km (560 miles) above Pittsburgh. They’ll be traveling toward each other at 32,880 mph!

If they don’t collide, everyone who has anything to do with satellites will breathe a sigh of relief because there will be that much less out-of-control space junk for their own satellites to hit.

If they do collide they won’t hurt us. At best we’ll see a few shooting stars as the bits burn up in Earth’s atmosphere. But we probably won’t see anything because Pittsburgh’s cloud cover will be 40% at that point. Check out the Clear Dark Sky chart for the forecast (screenshot below).

Here’s the original collision prediction from LeoLabs, an outfit in California that tracks space junk and potential collisions.

See KDKA’s announcement with video.

And here’s a more in depth article from Forbes Magazine.

In the meantime, LeoLabs revised their estimate to a pass distance of 13-87 meters and a 1 in 1000 chance of collision.

I’ll bet we won’t see any stars tonight.

(screenshot of space junk collision from PBS Be Smart video; click on the caption to see the original video)

UPDATE on 31 January 2020: No, they didn’t hit but they came mighty close. Analysis by LeoLabs at The IRAS / GGSE 4 Close Approach.

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)