15 November 2021, Pittsburgh, PA

If you live in the U.S. Eastern time zone, set your alarm for 3:30am Friday morning to step outside and watch the moon turn pink.

In what will be the longest partial lunar eclipse in 600 years, the moon will reach maximum darkness — and pinkness — at 4:02am EST, best seen from North America, the Pacific and eastern Russia.

Why pink? The Guardian explains, “During a total lunar eclipse, when the moon is in the Earth’s shadow, the only light reaching the moon passes through the Earth’s atmosphere. That produces a red tinge, or a deeper red colour after big dirty volcanic eruptions.”

The eclipse will happen at the same time everywhere (UTC) but local time will differ. In Pittsburgh the eclipse will end just before sunrise and then the moon will set.

Will we see the moon turn pink in Pittsburgh? Not well, if at all. In this century the 19th of November has been cloudy 75% of the time. Friday’s forecast says sky cover will be 50% at 4am. Check Pittsburgh’s Clear Sky Chart on Thursday 18 Nov before you set your alarm.

Our best chance for seeing this eclipse is to watch it Live at timeanddate.com. I’ll be up at 4am anyway to write this blog. I’ll let you know what I see.

p.p.s. Here’s an interesting factlet from timeanddate.com: “An eclipse never comes alone! A solar eclipse always occurs two weeks before or after a lunar eclipse.” Indeed, there will be a solar eclipse on 4 December 2021 but we’ll have to be in Antarctica to see it.

(photo from Wikimedia Commons, map from NASA.gov)

5 November 2021

This week clear skies and thin cirrus clouds produced optical phenomena in the sky.

On 3 November the waning crescent moon rose just before sunrise, reminding me of the upside down rainbow I saw two days before.

On Monday afternoon the sky had a thin skim of icy cirrus clouds and contrails that did not obscure the sun but allowed its light to create arcs and sundogs. This was the first time I’ve ever seen an upside down rainbow, the rare circumzenithal arc.

When the sun is low, arcs curve away [from it]. The circumzenithal arc, one of the most colorful of the ice-crystal phenomena, is always seen high in the sky. Its curve is centered on the zenith, and it is seen only when the sun is within 18-26 of the horizon.

— National Audubon Society: Field Guide to North American Weather

Here are two photos of the arc at 4:22pm, 1 Nov 2021.

Twenty minutes later the arc was gone but sundogs appeared as bright spots to the left and right of the sun. In this photo from Schenley Park Golf Course, one sundog is accentuated by a contrail. Downtown Pittsburgh is in the distance.

Check out this amazing photo of a halo, two sundogs and a circumzenithal arc in Riedbergpass, Germany. I’d love to see this one day. Keep looking up!

(photos by Kate St. John)

18 October 2021

Yesterday evening around 6pm rain obscured the northeastern horizon — Larimer, East Liberty and Shadyside. Eventually the cloud moved over us and dropped white pellets that clicked on the windows and bounced off the windowsills. There was no storm, just a dark cloud that ought to have been raining — except it wasn’t wet.

Was it hail? Was it sleet? Was it graupel?

I wasn’t outdoors to examine the pellets — they melted almost instantly — but I thought of graupel, also called snow pellets, because it was seven years ago this month (4 Oct 2014) that I first saw and wrote about it: Graupeling.

Did any of you see yesterday’s icy precipitation in the East End? What was it?

The National Weather Service has a helpful chart.

(photo from Wikimedia Commons, chart from the National Weather Service in Pittsburgh)

5 October 2021, 8:45am

It’s foggy this morning in Pittsburgh as it has been for several days. On Saturday, heavy dew gleamed at Frick Park and laced the spider webs with beads of moisture.

Today the temperature is warm enough under the trees that there is no fog beneath them though there is plenty above.

On Friday at Schenley Park we could see at ground level but fog above the trees made the sun look like a moon under the arch of the Panther Hollow Bridge.

When the fog cleared, the Cathedral of Learning emerged as from a magical kingdom.

Today the fog has intensified in the last hour, no birds are stirring in the trees and Ecco is waiting at the Cathedral of Learning to start his day.

(photos by Kate St. John & from the National Aviary snapshot camera at Univ of Pittsburgh)

2 October 2021

Last month saw many beautiful sunrises, a few of which I captured outside my window.

I’ve published one or two in earlier articles. Here they are all together.

(photos by Kate St. John)

27 Sep 2021

Tornado forecasting is better than it used to be but we always want earlier warnings and better accuracy. Now, thanks to computer modeling, “scientists have identified a key feature of big storms that could make such extreme weather events easier to predict.” The feature is a wispy cloud in the stratosphere called an above-anvil cirrus plume that is visible by satellite.

When most storms form they stay in the troposphere, the layer of the atmosphere where the majority of our planet’s weather takes place. But occasionally, they “punch up” into the stratosphere, creating mountains of clouds that trail wispy formations called above-anvil cirrus plumes (AACPs). These high-flying clouds have been linked to high winds, hailstorms, and tornadoes on the ground.

— Science Magazine: Supercell storms act like atmospheric mountains

These special clouds are on the downwind side of the supercell and are visible 10-30 minutes before the next stage in tornado formation.

Modeling indicates they form for the same reason as banner clouds on the leeward side of isolated mountains. Here’s an example at the Matterhorn.

See why violent storms are like mountains in stratosphere in the video below. Read more in Science Magazine.

p.s. Sometimes anvil clouds simply dissipate. That’s what happened to this cloud after sunrise in Pittsburgh on 18 September 2021.

(photos from Wikimedia Commons, Kate St. John, AACP screenshot from Science Magazine video)