Category Archives: Weather & Sky

Lots Of Water This Week

Waterfall in Schenley Park, 20180223_122714

Last week heavy rain swelled this waterfall in Schenley Park.  Again!

I filmed this video after heavy rainfall in February but the waterfall looked the same this week after record snow on April 2 (2.8") and heavy downpours on April 4 and 5.

So far we've had more than 16 inches of precipitation in 2018. That's almost 7.5 inches above normal in only 14 weeks.

Lots of water!

 

p.s. We have a dusting of snow this morning in Pittsburgh.  Will it ever end?!?

(video by Kate St. John)

How Early Is Spring This Year?

Snow this morning in Pittsburgh, 2 April 2018, 7:30am (photo by Kate St. John)
Snow this morning in Pittsburgh, 2 April 2018, 7:30am (photo by Kate St. John)

How early is Spring this year? That's a hard question to answer.

This morning we have snow again in Pittsburgh and heavy snow-cloud skies. Spring feels late and yet it was early at first.

The animated map below from the National Phenology Network (NPN) shows the emergence of leaves across the Lower 48 States. NPN uses honeysuckle leaves as their marker plant and so do I.  The blue color shows late emergence, red means early.  Our leaves were 20 days early in Pittsburgh.

USA National Phenology Network Spring Leaf Anomaly, 30 March 2018 (from usanpn.org)
USA National Phenology Network Spring Leaf Anomaly, 30 March 2018 (from usanpn.org)

Here's proof from February 20, 2018.

Honeysuckle leaves open in the heat, 20 Feb 2018 (photo by Kate St. John)
Honeysuckle leaves open in the heat, 20 Feb 2018 (photo by Kate St. John)

Since then Nature did a 180-degree turn and handed us a series of cold snaps capped by snow.  Our wildflowers have not bloomed yet.  Last year they were two to three weeks early and had gone to seed by the end of March.

Fortunately NPN tracks first blooms as well, using lilacs as the marker plant.(*)  On the map below you can see the Southeast bloomed 20 days early.

USA NPN Spring Bloom Anomaly, March 30, 2018 (from usanpn.org)
USA NPN Spring Bloom Anomaly, March 30, 2018 (from usanpn.org)

But we aren't on the bloom map yet.

When will our wildflowers bloom?  We'll have to wait and see.

 

(photo by Kate St. John. Animated maps from usanpn.org)

* From the USA NPN website: These models were constructed using historical observations of the timing of first leaf and first bloom in a cloned lilac cultivar (Syringa x chinensis'Red Rothomagensis') and two cloned honeysuckle cultivars (Lonicera tatarica 'Arnold Red' and L. korolkowii 'Zabelii').

The Water Table Is Rising

Today in Pittsburgh it's raining again and it's not going to stop until Sunday.  The rivers are rising and so is something else.  The water table!

Whenever it rains some of the water runs into creeks, streams and storm sewers while the rest soaks into the ground.  With an extra 3.22 inches of rain so far this month the ground is saturated (February 1-21).  The excess will double in the next few days as 3 more inches fall.

If you've ever dug a hole in wet ground you know it fills with water once it's below the water table.

What is a basement but a hole in the ground?

In Pittsburgh we have basements and many of them are damp right now.  The video shows why.

So here's the total precipitation forecast for Thursday Feb 22 through Sunday Feb 25.

U.S. total precipitation forecast, Days 1-3, beginning Thurs 22 Feb 2018, 12Z (image from National Weather Serive)
U.S. total precipitation forecast, Days 1-3, Thurs 22 Feb, 8am through Sun 25 Feb 2018 (image from National Weather Service)

Oh no! The water table is rising.

 

(photo and video credits:
video from YouTube; screenshot from this great educational video about the water table and pollution from Penn State (15:57); map from the National Weather Service; click on the image to see its source
)

Record Heat

Honeysuckle leaves open in the heat, 20 Feb 2018 (photo by Kate St. John)
Honeysuckle leaves open in the heat, 20 Feb 2018 (photo by Kate St. John)

Yesterday we put on our summer clothes and this honeysuckle bush put out new leaves.  It was summer in February.

At 78 degrees F the high temperature broke two Pittsburgh records:  a new high for February 20 (formerly 68 degrees in 1891) and a new high for the entire month of February.  It was 37 degrees above normal.

When you look at yesterday's map you can see how it happened. The jet stream dipped across the Northern Rockies and Plains, then abruptly turned north over the Texas Panhandle.  It was only 3 degrees F in western Nebraska while we were nearly 80.  The narrow temperature gradient -- that yellow line across the Midwest -- continues to produce heavy rain.

U.S. high temperature forecast map for 20 Feb 2018 (from the National Weather Service)
U.S. high temperature forecast for 20 Feb 2018 (map from the National Weather Service)

Meanwhile, like a yo-yo, we're headed back to normal tomorrow and will lose those 37 degrees.  Today's our last chance for record heat.

 

(photo by Kate St.John. Temperature map from the National Weather Service; click on the image to see the latest map)

High Water!

Moderately high water on the Monongahela River at Duck Hollow, 15 Feb 2018, 9:30am (photo by Kate St. John)
Moderately high water on the Monongahela River at Duck Hollow, Thursday 15 Feb 2018, 9:30am (photo by Kate St. John)

SCROLL DOWN TO SEE UPDATES.
This week in the space of 40 hours -- Feb 14, 4:30pm to Feb 16, 9:50am -- the Pittsburgh region received 2.5+ inches of rain.  At first it flooded creeks and streams. Now it's in the Allegheny, Monongahela and Ohio Rivers.

Since I live near the Mon River I went down to Duck Hollow to see what it looked like.  In video below from Friday morning 16 Feb, the island of treetops in Thursday's photo had disappeared.

Today (Saturday) the rivers are even higher and I don't have to visit them to find out.  The PennDOT traffic cams tell the story.

In Downtown Pittsburgh there's a stretch of I-376 westbound called "The Bathtub" that dips into the Mon River flood zone.  Last month it was the site of exciting river rescues when two people drove their vehicles into it as the water was rising.  Click here to see a Live Video of the rescues.

This morning The Bathtub is full, as shown in before-and-after photos from the PennDOT traffic cam:  Yesterday (Feb 16) on the left, today (Feb 17) on the right, both at 7:20am.

PennDOT traffic cam at The Bathtub: Feb 16 2018 (before the flood) and Feb 17 (after)
PennDOT traffic cam at The Bathtub: Feb 16 2018 (before the flood) and Feb 17 (during)

The Allegheny is flooding, too, at the 10th Street Bypass.

PennDOT traffic cam at the 10th Street Bypass, 17 Feb 2018, 7:20am
PennDOT traffic cam at the 10th Street Bypass, 17 Feb 2018, 7:20am

All of this is "Minor" flooding in Pittsburgh per the National Weather Service.  (Flooding on the Youghiogheny River in Sutersville nearly reached the "Major" stage last night.  It's receding now.)

Later this morning I'll go down to Duck Hollow and see what's up.  The water's up for sure!

UPDATES: Saturday Feb 17 & Sunday Feb 18.

The Monongahela River crested around mid morning on Sat. February 17 and started to go down a little by noon.
17 Feb 2018, 9:30am:  I saw small fish swimming in the parking lot! Two Canada geese float by beyond the guardrail.

No parking today!

At the edge of the Mon River at Duck Hollow, 17 Feb 2018, 9:30am
At the edge of the Mon River at Duck Hollow, 17 Feb 2018, 9:30am

17 Feb 2018, 12:11pm: The water has started to recede, though not by much.

18 Feb 2018, 6:00am:  The Bathtub on I-376 and the 10th Street Bypass are still closed due to flooding.  The water is about 1/3 to 1/2 gone.

 

 

(Duck Hollow photos and videos by Kate St. John. Traffic cam snapshots from PennDOT)

Back Into the Deep Freeze

Bald eagle with ice on his forehead and belly, Crooked Creek, Jan 2018 (photo by Steve Gosser)
Bald eagle with ice on his forehead and belly, Crooked Creek, Jan 2018 (photo by Steve Gosser)

After a balmy Thursday and Friday the temperature is plummeting tonight to 5oF.

During the last deep freeze, Steve Gosser photographed a bald eagle at Crooked Creek with iced feathers on his belly and head. Notice how his head feathers are standing up as if he used hair gel!

The eagle's ice shows the great insulation power of feathers and how extreme cold can form ice very quickly when the eagle lifts his head out of the water.

He'll be getting another chance to wear icicles this weekend.  Brrrrr!

 

(photo by Steve Gosser)

Why Is It Warming So Fast?

  • Friday, 5 Jan 2018

Egads, it was cold last weekend!  Here in Pittsburgh it was -6 to 11 degrees F, but yesterday things turned around.  Sunday (7 Jan.) started at -6oF but warmed to a high of 30.  Today will be above freezing and by Thursday the high will be 64oF.  That's a swing of 70 degrees in only four days!

The slideshow above shows this in color for January 5, 8, 11 and 12.

I'm not complaining that we're out of the deep freeze but ... this weather is really odd.  Why did it get so cold and why is it warming so fast?  Why don't we have a moderate winter like we used to?

Crazy as it sounds, it's because the arctic is warming faster than the rest of us.  When there's not a big temperature difference between the North Pole and the mid-latitudes (us) the jetstream slows down.  When it's sluggish, it wobbles in high amplitude loops that dip as far south as Florida(*).

The video below explains why.  I recommend watching it twice; you see more the second time.  (My end notes have info on millibars, etc.)

So when a cold loop settles over us, we're really cold and when it moves on we're really hot.  It happens quickly in both directions.

Don't put away your winter clothes on Thursday.  The forecast says it'll be 5 degrees on Saturday night.

 

(temperature forecast maps from NOAA; Jet stream explanation by Jennifer Francis on YouTube)

Definitions and notes:

  • A millibar (or mb) is a unit of air pressure.
  • The average air pressure at sea level is 1013.25 millibars = 14.7 pounds.
  • What's the significance of 500 millibars?   The 500 millibar pressure zone is where air pressure is half what it was at sea level, halfway up in the atmosphere. Since air pressure varies as weather systems move above us, the 500mb map is a great diagram of what the weather systems are doing.    Here's the air pressure map for Friday 5 Jan 2018 at 1200z (8am).  Notice that the pressure lines echo Friday's temperature map above.
  • (*) I wrote above that the jetstream dips as far south as Florida.  Well, it dips even further than that.  In June 2016 the northern jetstream crossed the equator and joined the southern one!

At Cape Cod: Before and During the Storm

Before the storm: Icy blue ocean at West Dennis Beach, Mass. 3 Jan 2018 (photo by Barb Lambdin)
Before the storm: Icy blue ocean at West Dennis Beach, Mass. 3 Jan 2018 (photo by Barb Lambdin)

On the day before the "bomb cyclone" hit Massachusetts my sister-in-law, Barb Lambdin, sent me two photos of the frozen ocean at West Dennis Beach, Cape Cod.   Intrigued by the coming storm, I asked her to take more photos when it hit.

The photo locations are part of the story:

  1. Before the storm: West Dennis Beach on the ocean side.
  2. During the storm: Corporation Beach in the protected middle of the bay shore.

Map of Massachusetts showing 1: oceanside photos at West Dennis Beach, 2: bayside photos at Corporation Beach (from Wikimedia Commons, annotated)
Map of Massachusetts. 1: oceanside photos at West Dennis Beach, 2: bayside photos at Corporation Beach

 

BEFORE THE STORM:

Above, the ocean was so calm on 3 January 2018 that ice had formed in flat sheets and blue-green water ponded on top.

The waves were small and slushy (below).  Barb calls them Frozen Margarita waves.

Before the storm, slushy waves at W Dennis Beach, MA 3 Jan 2018 (photo by Barb Lambdin)
Before the storm, slushy waves at W Dennis Beach, MA 3 Jan 2018 (photo by Barb Lambdin)

 

DURING THE STORM:

On 4 January it was too windy and dangerous on the ocean side so Barb went to the bay side at Corporation Beach.  The two photos below were taken at high tide.

Keep in mind that this is the calm side of Cape Cod yet the waves are high and about to flood the parking lot.  I have never seen waves break at Corporation Beach!

During the storm: Corporation Beach at high tide, Dennis,Mass. 4 Jan 2018 (photo by Barb Lambdin)
During the storm: Corporation Beach at high tide. Dennis, MA 4 Jan 2018 (photo by Barb Lambdin)

This high tide set a record at Boston, 60 miles north across the bay.

During the storm: Corporation Beach at high tide, Dennis,Mass. 4 Jan 2018 (photo by Barb Lambdin)
During the storm: Corporation Beach at high tide. Dennis, MA 4 Jan 2018 (photo by Barb Lambdin)

For more information and cool graphics see The 10 best images of this week's historic bomb cyclone in the Washington Post.

Is this the worst nor'easter we'll see this winter? Who knows.

p.s. Why is it so cold?

Actually it's extremely cold in the eastern U.S. but very warm in the West (click here for Departure From Normal Temperature graphic).

Four years ago we experienced the Polar Vortex of 2014 when the jet stream wobbled southward. It's happening again. And it's a feature of climate change.

Learn more at CBCnews: Why has it been so cold? Here's what science says.

 

(photos by Barb Lambdin. Massachusetts map from Wikimedia Commons. Temperature map from the National Weather Service; click on the images to see the originals)

Black And Blue Ice

Transparent ice coating the street in Sapporo, Japan (photo from Wikimedia Commons)
Transparent ice coating the street in Sapporo, Japan (photo from Wikimedia Commons)

28 December 2017:

This morning it's 3o F in Pittsburgh with a forecast high of 15o F.  Yesterday was just as cold.  It's 20 degrees below normal here.

Less than a week ago, on 22 December, the low was 40o with a high of 57o F.  It was 19 degrees above normal.  To accomplish this temperature swing it rained half an inch on December 23 and froze solid on Christmas Eve night.  We had black ice on Christmas Day.

Black ice isn't really black.  It just looks that way because it's such a thin, smooth coating of clear ice that the dark pavement shows through.

Technically speaking "black ice" forms when pavement looks dry but its porous surface contains water.  When that water freezes it's invisible.  So the photo at the top isn't really "black ice" (it was probably laid down by freezing rain) but who can find a photo of something invisible?

Pittsburgh has black ice but we don't have blue ice.

Blue ice is very old ice from the lowest layers of a glacier.  It's blue because the weight of the glacier above compressed all the air bubbles out of it.  The lack of air makes the ice look blue like sea water.

Blue ice at a glacier in Iceland (photo from Wikimedia Commons)
Blue ice at a glacier in Iceland (photo from Wikimedia Commons)

I learned about blue ice in the description of this photo taken in Iceland.

So... black ice occurs where temperatures move above and below freezing (Pittsburgh).  Blue ice occurs where it's so cold that the glaciers are old (Iceland).

Pittsburgh or Iceland?  Where would you rather be on this cold day?

 

p.s. Be careful out there!  If you fall on the ice you'll be black and blue.

(photos from Wikimedia Commons. Click on the images to see the originals.)

Crazy Warm

Barrow, Alaska as seen from the air, Aug 2007 (photo from Wikimedia Commons)
Barrow, Alaska as seen from the air, Aug 2007 (photo from Wikimedia Commons)

The computer said, "Those numbers are too high. They must be in error. Throw them out."  And so Barrow, Alaska disappeared from the climate analysis database.

Fortunately a lot of people missed Barrow when it was gone. In fact they suspected it  might disappear some day because it's so unusual.  The error was found quickly and the raw data will be restored.

What happened?

This month more than a year's worth of temperature data for the northernmost point in the U.S. -- Barrow, or Utqiávik, Alaska (see arrow) -- automatically disappeared from the National Centers for Environmental Information temperature analysis system because it looked so out of whack.

Barrow, Alaska locator map (image from Wikimedia Commons; arrow added)
Barrow, Alaska locator map (image from Wikimedia Commons; arrow added)

Why would a computer throw away real data?

Computers that collect automated weather data have algorithms that test for wild abnormalities so that instrument errors are isolated (rejected) from the clean data calculations.  For instance, when a weather thermometer breaks or goes offline, the temperature is recorded as "zero."  When this happens in July in Pittsburgh it's so obviously incorrect that the software rejects it. Algorithms for climate analysis are even more stringent because a change to an instrument's location can look like a trend even though it isn't.

Here's why Barrow looks crazy to a computer.  This graph by Derek Arndt at climate.gov shows circles for Barrow's 1979-1999 average monthly temperatures, triangles for 2000-2017.  Notice that for most of the year those 20-year averages are pretty close but for October, November and December they're widely different.  Computers don't like that!

Average Monthly Temperature at Barrow in two eras 1979-1999 vs 2000-2017 (graph from NOAA)
Average Monthly Temperature at Barrow in two eras 1979-1999 vs 2000-2017 (graph from NOAA)

Barrow is experiencing rapid warming because there's a lot less sea ice than there used to be.  When ice crowds the shore in the fall, Barrow gets cold, but now the ice recedes so far in the summer that it takes months longer to reach the town.

It's crazy warm in Barrow.

 

A tip of the hat to Angela Fritz at the Washington Post for her 12 December article that brought this to my attention.  Read all about it at NOAA's Beyond the Data blog: Alaskan North Slope climate change just outran one of our tools to measure it.

(photo and map of Barrow, Alaska from Wikimedia Commons. Graph from climate.gov. Click on the images to see the originals)

p.s. Barrow is now called by its native Alaskan name, Utqiávik.