Category Archives: Weather & Sky

Hurricane Rain

Hurricane Ian spins northward (GOES East satellite Great Lakes sector, 30 Sept 2022, 3:40am to 5:30am from NOAA)

30 September 2022, 6am

UPDATE 30 SEPT, 6 PM. See UPDATED info at end

After wrecking a swath of Florida, Hurricane Ian popped out over the Atlantic Ocean, gained strength, and is bearing down on the Carolinas. Though Pittsburgh is quite far inland we will see the remnants of Hurricane Ian’s rain on Saturday.

These maps show total rainfall forecasts for the next three days as Hurricane Ian moves up the eastern U.S.

  • Quantitative Precipitation Forecast, Fri 30 Sep - Sat 1 Oct 2022 (map from NOAA)

Quantitative Precipitation Forecasts, Continental US, 30 Sept to 3 Oct 2022 (maps from NOAA)

Pittsburgh will receive less than an inch of precipitation because Ian is tracking south and east of here. Fortunately this is far different from our experience of Hurricane Agnes 50 years ago.

UPDATE 30 SEPT, 6 PM. I have corrected the captions on the slideshow based on an email from Dick Rhoton. Note that the slideshow maps show total rainfall potential, no matter what cause.

This map shows rainfall potential from Hurricane Ian alone — anything greater than an inch — as of 30 Sept 2022, 6am.

Hurricane Ian total rainfall potential, 30 Sep through 2 Oct 2022 (map from NOAA)

(maps and animation from NOAA; click on the captions to see the originals)

More Heat Ahead

Heat at sunset (photo from Wikimedia Commons)

20 September 2022

Now that summer’s heat is over we may be fooled into thinking climate change is no longer affecting us. Unfortunately, above normal temperatures are predicted for most of the U.S. for the next three months. Southeastern Alaska is the only place with any chance of being cooler than normal.

U.S. 3-month temperature outlook, Oct-Dec 2022 (map from NOAA

Heat and drought often go hand in hand.

The seasonal drought outlook through the end of 2022 indicates New England will finally see a break in their drought, perhaps hastened by rain from a downgraded hurricane. But there is no help for the American West where the drought persists and gains new ground (see yellow on the map).

U.S. 3-month drought outlook (map from NOAA)

The drought in California is particularly dire.

California drought (photo from Wikimedia Commons)

Why does this matter to the rest of us? Because the worst drought is in the Central Valley and that’s where more than half of the U.S. fruits, vegetables, and nuts are grown.

(photo credits in each caption; click on the captions to see the originals)

Cloud Like a Spaceship

Lenticular cloud over Aberdeen, Scotland (photo from Wikimedia Commons)

9 September 2022

It looks like a spaceship but it’s actually a cloud.

Here’s another one at Palm Desert, California.

Lenticular cloud over Palm Desert, California (photo from Wikimedia Commons)

And another one — quite ominous! — in the mountains in Patagonia. Do I see a mouth on this cloud?

Lenticular cloud darkens the sky over Patagonia (photo from Wikimedia Commons)

These are all lenticular clouds which form when the wind blows horizontally toward a fixed object that forces the air to rise and fall in a wave. If the fixed object is a mountain and the air is moist it forms a cloud on top of the mountain. The cloud stays right there, thumb-tacked to the sky, as shown in this time lapse from Mount Teide in the Canary Islands.

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

Sky Show

Sunrise in Pittsburgh, 19 August 2022 (photo by Kate St. John)

27 August 2022

This week’s weather put on a sky show.


Cloud stacks, 22 August 2022 (photo by Kate St. John)

Lightning and lots of it! Dave Dicello captured a split lightning bolt simultaneously hitting BNY Mellon and the east end of Duquesne University (more than 1/2 mile away) on Sunday morning 21 August. Click here for his latest sky/panorama photos or here for his website.

Anticrepuscular rays are relatively rare and appear opposite the sun at sunrise or sunset. Caused by the backscattering of atmospheric light, the rays we saw on 23 August spanned the sky. I took a photo from my window but it pales in comparison to Dave DiCello’s (@DaveDiCello) from a different vantage point. His tweet and video are shared below my photo.

A cloud shadow across the sky, an anticrepuscular ray, 23 August 2022 (photo by Kate St. John)

The Moon and Venus rise together… my unprofessional cellphone photo on 25 August. Through a window but you get the idea.

Moon and Venus before sunrise, 25 August 2022 (photo taken through a window by Kate St. John)

(photos by Kate St. John, shared tweets by Dave DiCello)

Seen This Week

Long shadows are back again, 12 August 2022 (photo by Kate St. John)

20 August 2022

The days are getting shorter and shadows are getting longer. Pittsburgh had one and a half more hours of daylight on the summer solstice, just two months ago, than we do today.

Late summer flowers are attracting bees.

Allium flower with bee, 16 August 2022 (photo by Kate St. John)

Ornamental grasses are going to seed.

Ornamental grass at Phipps (photo by Kate St. John)

And the clouds have been interesting.

Puffy clouds over Millers Ponds, Crawford County, 15 August 2022 (photo by Kate St. John)

Can you see the face in the cloud below?

Glowing eyes in the face in the cloud, 17 August 2022 (photo by Kate St. John)

Keep looking up.

(photos by Kate St. John)

Variably Cloudy

Sunrise on 31 July 2022 (photo by Kate St. John)

5 August 2022

This week the clouds at sunrise varied from brooding horizontal stripes to dramatic ragged puffs.

Sunrise on 4 August 2022 (photo by Kate St. John)

This tall stack presaged scattered thunderstorms though none had been predicted.

Cloud stack on 4 August 2022 (photo by Kate St. John)

Twice this week isolated rain clouds created spectacular rainbows half an hour before sunset. This one on 4 August has a faint second rainbow above it.

Rainbow(s) on 4 August 2022 (photo by Kate St. John)

On 1 August the pot of gold was in Shadyside.

Rainbow on 1 August 2022 (photo by Kate St. John)

(photos by Kate St. John)

Wrapping Up July

St. John’s wort on the South Side, 17 July 2022 (photo by Kate St. John)

30 July 2022

Wrapping up July …

St. John’s wort’s yellow flowers always attract my attention because the plant shares my name. Find out what’s in the name in this vintage article from 2012.

This month I learned that chicory flowers (Cichorium sp) last only one day. On a foggy morning I found this one, barely open and doomed to wilt by afternoon. Learn more at #bioPGH Blog: Chicory, Dickory, Dock – The Flowers are on the Clock.

Chicory opening on a cloudy morning, Schenley Park, 22 July 2022 (photo by Kate St. John)

We had several spectacular sunrises in July, especially this on the 17th.

Dawn on 17 July 2022 (photo by Kate St. John)

Soon we’ll say good morning to August.

(photos by Kate St. John)

Summer Snowflake

Queen Anne’s Lace, Schenley Park, 22 July 2022 (photo by Kate St. John)

23 July 2022

The flowers on Queen Anne’s lace (Daucus carota), or wild carrot, are so lacy and regular that they resemble snowflakes when viewed from above, especially in black-and-white.

Queen Anne’s Lace, black-and-white (photo by Kate St. John)

Look closely and you’ll see that the tiny flowers inside the umbel have 5 regular parts. Step back to see the pattern of 5’s replicating to the edge.

Queen Anne’s lace umbel is 5-sided (photo by Kate St. John)

Unlike winter’s 6-sided snowflakes (below) these summer “snowflakes” have only five.

Snowflake (photo by Alexey Kljatov via Wikimedia Commons)

p.s. See Vicki Dinsmore’s comment below about wild parsnip which is not the same thing!

(photos by Kate St. John and from Alexey Kljatov via Wikimedia Commons)

So Hot. Getting Hotter

22 July 2022

This week has been and will be unusually hot around the world. On Tuesday in Britain, where there is virtually no air conditioning, the high temperature was a record-breaking 40.3 degrees Celsius, 104.5 degrees F! It was as hot as Phoenix, Arizona without the respite of air conditioning and community cooling centers.

Red sun through smoke of the Woolsey Fire, California, 9 Nov 2018 (photo from Wikimedia Commons)

Back in the 1970s and 1990s climate change was slow to ramp up so we fooled ourselves by saying (1) Nothing’s changed yet so it’s not going to change, and (2) Climate change will be manageable because it won’t happen fast.

Wrong on both counts. This animation from NASA Goddard Institute of Space Studies shows world temperature anomalies in Fahrenheit, 1880 – 2021. The fastest changes have occurred in the last 5-10 years!

Temperature anomalies in Fahrenheit, 1880-2021 (from NASA, Goddard Institute of Space Studies)

So hot! And getting hotter.

(photos from Wikimedia Commons, animation from NASA Goddard Institute of Space Studies)