Category Archives: Weather & Sky

Fall Is Here

Misty walk at Panther Hollow Lake, Schenley Park, 10 Sep 2021 (photo by Kate St. John)

11 September 2021

The weather has been pleasant with low humidity and highs in the 70s. Chilly fall mornings produce a mist on Panther Hollow Lake.

Asters are blooming right on time …

Asters (photo by Kate St. John)

… but this hawthorn tree is confused, opening two flowers and a leaf in September.

Hawthorn tree puts out two flowers and a leaf, Schenley Park, 10 September 2021 (photo by Kate St. John)

This eastern screech-owl confirms it’s fall when he peeks from his well known roost on 4 September. Though screech-owls breed in Schenley Park, they only use this roost during the non-breeding season.

Eastern screech-owl at the winter roost, Schenley Park, 4 Sep 2021 (photo by Kate St. John)

My least favorite hot weather will return tomorrow through Tuesday, forewarned by this morning’s red sunrise.

Red sky at morn, sailors forewarn.

Sunrise in Oakland, Pittsburgh, 11 Sep 2021 (photo by Kate St. John)

(photos by Kate St. John)

Any Day with a Crow in it is Full of Promise

Sunrise on 15 August 2021 (photo by Kate St. John)

21 August 2021

Pittsburgh’s crows have finished breeding so the local families now gather in a communal roost. Last week I counted 100 of them, mostly fish crows, congregating at dusk on Ascension Church’s knobby towers (left) and the Cathedral Mansions roof (right). While the sky still glows after sunset they fly west to roost beyond the VA Hospital.

Last month they congregated long before sunset near the Cathedral of Learning but they’ve been warned not to do that. On 29 July a peregrine chased the pre-roost flock out of Oakland. I watched her repeatedly dive-bomb them, harass an individual low-flying crow, and push the flock east into the trees in Shadyside. As soon as they had settled far away, Morela flew back to the Cathedral of Learning.

The crows still fly west into the sunset and east into the sunrise but now they give the Cathedral of Learning peregrines a wide berth.

Sunrise with three crows heading east, 15 August 2021 (photo by Kate St. John)

Any day with a crow in it is full of promise.

— Candace Savage

(photos by Kate St. John)

A few days later: Here’s a fuzzy picture of them on Ascension Church towers.

Crows congregating on Ascension Church towers (photo by Kate St. John)

What About That Lightning?

Lightning in Dallas, 2015 (photo from NOAA Weather in Focus Photo Contest via Wikimedia Commons)

19 August 2021

Curious about lightning? Today’s article is a scavenger hunt for lightning facts. Two vintage blog posts provide the answers.

Looking Forward to a Little Less Lightning (click the link) will tell you …

  • Which month produces the most lightning in Pittsburgh?
  • If a person is struck by lightning what’s their percentage change of surviving it?
  • Who holds the world record for being struck by lightning? How many times was he hit? Did it eventually kill him? And a much longer story about him here.

In Why Does Thunder Rumble? you’ll find out:

  • How long is a lightning bolt?
  • How far away is that lightning? Plus an easy technique for answering this question.
  • (And of course) Why does thunder rumble?

And a bonus! Here’s a 10 minute video of lightning in slow motion recorded in Singapore by The Slow Mo Guys. (I’ve skipped the video forward to just before the lightning starts.)

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

In Tidewater Virginia

Sunrise over the Pagan River, 15 July 2021 (photo by Kate St. John)

17 July 2021

This week my husband and I have been visiting family in Tidewater Virginia, our first long trip since the COVID-19 shutdown. Everyone’s vaccinated (& some had COVID last winter) so at last we’re making the “Real Hugs Tour.”

It is hot. 92 degrees F near the water, 100 degrees on the roads in the interior. Every morning I take a walk before it gets too unpleasant.

At the ocean I was pleased to see saltwater birds and southern songbird species. Favorite birds on the bay side of First Landing State Park were least, royal and sandwich terns plus a blue grosbeak (eBird checklist here).

View of the bay from First Landing State Park, 14 July 2021 (photo by Kate St. John)

I also encountered a lot of bug sounds …

… and a dragonfly that repeatedly perched on a twig in the stiff wind. Its behavior reminded me of a kestrel.

Dragonfly holding onto a twig in a stiff wind, 14 July 2021 (photo by Kate St. John)

The landscape is beautiful and welcoming until you stand in the sun.

Low tide at Windsor Castle Park, Smithfield, Virginia, 16 July 2021 (photo by Kate St. John)

Blackberries ripen in the heat.

Blackberries, Smithfield, 16 July 2021 (photo by Kate St. John)

House finches are prolific breeders in the hanging baskets on my sisters porch. This brood froze as we peeked under the fern in one basket while another house finch couple was building a new nest in the next basket.

House finch nestlings in a hanging basket, 15 July 2021 (photo by Kate St. John)

In Pittsburgh it is 10-15 degrees cooler but we will miss the sea breeze when we get home tomorrow.

(photos by Kate St. John)

Flash Floods Every Day

Flash floods on Nine Mile Run last week left flood debris up to my ears! (photo by Kate St. John taken on 10 July 2021)

11 July 2021

Southwestern Pennsylvania has always been prone to flash floods but last week was exceptional with a flash flood every day, three days in a row.

At 3pm on Wednesday 7 Jul 2021 a heavy downpour in the Nine Mile Run watershed caused a flash flood recorded by Upstream Pittsburgh‘s stream cam (video below, blurry because it’s raining). The downpour was so localized to the East End that it did not register on Pittsburgh’s official weather gauges. Flood debris showed that if I’d been on the Nine Mile Run Trail the water would have been up to my ears! (photo at top taken at 40.4263341,-79.9068387).

07 July 2021 Storm Timelapse at Nine Mile Run from Aaron Birdy on Vimeo.

On Thursday 8 July at 7pm a downpour over Pleasant Hills had devastating results as reported by CBS Pittsburgh.

And on Friday 9 July another localized thunderstorm let loose for half an hour in Squirrel Hill. I have no photos because I was driving down Braddock Avenue in the downpour, hoping the river on the road would not become a car-swallowing lake under the Parkway bridge. Fortunately the water ran off into Nine Mile Run. Another flash flood. I’m glad I was not on the trail.

As crazy as this is, it should not be a surprise. Pittsburgh is prone to flash floods, especially in Allegheny County as shown in the 35-year map of Flash Flood Reports from the National Weather Service.

Number of flash floods in 35 years by county, 1986-2020, in NWS Pittsburgh forecast area (image from NWS Pittsburgh)

We don’t need a particularly wet year for this to happen. Pittsburgh’s 2021 rainfall is actually 0.93 inches below normal as of today. The problem is that the rain falls all at once, especially in June and July.

Climate change is making the problem worse. A 2019 study found that extreme precipitation has increased 55% in the Northeastern US in my lifetime.

Heavy rain has increased across most of the United States, 1986-2016 (map from climate.gov)

This trend will continue in southwestern PA through the 21st century. (Click here to see where frequent heavy downpours will increase in the U.S.)

Brace yourself, Pittsburgh, for a lot of flash floods in the future. Sometimes every day.

About Nine Mile Run per Upstream Pgh (formerly Nine Mile Run Watershed Association): “Nine Mile Run is a small stream that flows through Pittsburgh’s East End, mostly underground. The 7 square mile Nine Mile Run watershed is home to the largest urban stream restoration in the United States, completed by the U.S. Army Corps of Engineers in 2006.” Upstream Pgh got its start with this project and now works throughout the region on community-oriented stormwater management projects, large and small, plus much more. Click here for their website.

p.s. If you’re not from the area you might not realize that “Pgh” is an abbreviation for Pittsburgh. We’re the only Pittsburgh with an “h.”

(photo by Kate St. John, videos from Upstream Pittsburgh and CBS Pittsburgh, maps from NWS Pittsburgh an climate.gov; click on the captions to see the originals)

Enchanting Sky and Flowers

Sunrise on 24 June 2021 (photo by Kate St. John)

26 June 2021

The sky was enchanting on Thursday morning while enchanter’s nightshade (Circaea lutetiana or perhaps Circaea canadensis) was blooming in Schenley Park.

Enchanter’s nightshade, Schenley Park, 25 June 2021 (photo by Kate St. John)

On 16 June, six of us were enchanted by mountain laurel and hundreds of pitcher plants blooming at Spruce Bog on top of Laurel Mountain.

  • Mountain laurel on Laurel Mountain, 16 June 2021 (photo by Kate St. John)

In the slideshow above, notice the leaf that’s wrapped and sealed into a tube. The structure was made by an insect. I don’t know which one.

p.s. Read more here about the enchanter’s nightshade name. Interestingly the plant is not in the nightshade family.

(photos by Kate St. John)

After The Storm

Sunset after the storm, 13 June 2021 (photo by Kate St. John)

Tuesday 15 June 2021

At 6pm on Sunday evening a violent thunderstorm blew through Pittsburgh with powerful wind gusts, hail and heavy rain.

Dave DiCello photographed the storm from the West End as it approached Oakland. The VA Hospital and the Cathedral of Learning are to the right of the lightning bolt.

Meanwhile my husband and I watched from our 6th floor apartment as a wind gust picked up the patio umbrella from the high-rise roof next door and blew it, Mary Poppins-like, until it crashed into our building. Then we saw no more as rain and hail battered our windows for half an hour, first from the north, then the east.

The tempest left behind flooding, downed trees, power outages, and a rainbow.

Rainbow after the storm, 13 June 2021 (photo by Kate St. John)

Yesterday morning I surveyed the damage after the cleanup had already begun. In a short walk I found trees down at Frick Fine Arts, Carnegie Library and Museum, and two small breaks on South Craig Street.

At Schenley Park the valley around Panther Hollow Lake was spared but the lake itself was full of flood water. This is by design. A flow control gate at the outlet holds back freshwater so that storms will not flood The Run.

Panther Hollow Lake holds back floodwaters from the storm, 14 June 2021 (photo by Kate St. John)

This morning the power was still out in parts of Squirrel Hill as I drove home from the grocery store.

My husband and I were fortunate. Our power never failed and that flying umbrella hit the wall below us and caused no damage.

p.s. The young Pitt peregrines are flying so well that they are hard to find. I saw both adults plus two of four juveniles on my Monday morning walk.

(photos by Kate St. John)

Why Are Clouds Flat On the Bottom?

21 May 2021

Discrete fluffy white clouds. When I photographed this field of rapeseed in Ohio I was struck that all the clouds are flat on the bottom. Why?

They look as if they are laid on a glass ceiling. The bottoms are at the same altitude. Here’s a similar sky in Australia.

Cumulus humilis clouds in New South Wales, Australia (photo from Wikimedia Commons)

These fair weather clouds are Cumulus humilis, “humble” clouds that are flat and wide.

If the rising air is strong enough they grow upward to become Cumulus mediocris

Cumulus humilis and mediocris (photo from Wikimedia Commons)

… and taller into Cumulus congestus which can end a fair weather day.

Cumulus congestus and cumulus mediocris (photo from Wikimedia Commons)

All of them have flat bottoms at the same altitude because …

The flat bottom of cumulus clouds defines the exact height at which a critical combination of temperature and air pressure causes water vapor within the rising current to condense into a visible cloud.

Chicago Tribune, Ask Tom about weather, 19 July 2015

The bottoms show where the dewpoint is.

A NOTE about the yellow field: Rapeseed (Brassica napus), in the mustard family, is grown for its oil-rich seeds. Cultivars with very low eruric acid become canola oil. “Rapeseed is the third-largest source of vegetable oil and second-largest source of protein meal in the world,” according to Wikipedia.

(photo by Kate St. John)

In the Family of Halos

22 May 2021

There were clouds on the eastern horizon when the sun rose in a spectacular sun pillar on Thursday morning 20 May.

According to Wikipedia (paraphrased):

The effect is created by the reflection of light from tiny ice crystals suspended in the air or in cirrus clouds.

The crystals are usually flat hexagonal plates that are oriented horizontally as they fall through the air. Each flake acts like a tiny mirror that reflects light sources positioned below it.

The presence of flakes at a spread of altitudes causes the reflection to be elongated vertically into a column. The larger and more numerous the crystals, the more pronounced this effect becomes. 

Wikipedia article on light pillars

Though it was 57 degrees F at sunrise that morning, the sky was cold.

Sun pillars have a lot in common with sun dogs. They are both in the family of halos.

Air Then and Now

50 million year-old spider and air trapped in amber (photo from Wikimedia Commons)

22 April 2021

If you want to know what the air was like 100 million years ago, look at the air trapped in amber. In 2013 scientists analyzed 538 samples and discovered that in the age of the dinosaurs there was less oxygen in the air than now. The concentration in the early Cretaceous period was only 10-15% compared to 21% oxygen today. It was similar to the available oxygen at Mount Everest Base Camp.

If you want to know what the air is like now in the U.S. check the 22nd annual State of the Air Report issued yesterday by the American Lung Association (ALA). Sadly, Pittsburgh is still in the top 10 of Bad Air cities for year-round particle pollution.

The State of the Air Report doesn’t even measure the rotten egg smell — hydrogen sulfide, H2S — that’s produced by U.S. Steel’s Clairton Coke Works and Edgar Thompson Works in Braddock.

High concentrations of H2S (widely recognized by its foul, rotten-egg odor) are registered all too often in the Mon Valley. In fact, so far this year there have already been 21 exceedances of Pennsylvania’s 24-hour average H2S standard – 13 at the Liberty monitor and eight more at the North Braddock monitor. 

GASP-pgh.org, State of the Air Report, 21 April 2021

This month has been especially bad. Here’s what it looked like last Sunday 18 April on Smell PGH’s crowd-sourced bad smell report.

In Pittsburgh, the nose knows.

That rotten egg smell (Tammany cartoon via Wikimedia Commons, text removed)

Read more about the air the dinosaurs breathed in this vintage blog: Ancient Air.

Read more about Pittsburgh air quality (Pittsburgh area air quality still gets failing grades) and what you can do about it at the Group Against Smog and Pollutiongasp-pgh.org.

p.s. The scientific paper about the air-in-amber research is here: https://www.sciencedirect.com/science/article/abs/pii/S0016703713003906

(photos from Wikimedia Commons, Smell PGH screenshot from the app; click on the captions to see the originals)