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.
"The Beaufort Gyre is acting strangely," said the news at Yale Environment 360. "Scientists say it could kick off a period of lower temperatures in Northern Europe."
The Beaufort Gyre is a wind-driven current in the Arctic Ocean. Traveling clockwise it keeps sea ice contained and moving so slowly that the ice thickens.
Every five to seven years the winds change direction and the gyre spins counter-clockwise, dumping icebergs and cold freshwater into the North Atlantic near Iceland. Then the winds switch back.
But now the winds haven't changed direction for a long time, arctic ice is melting, and freshwater from the continents is flooding the Beaufort Sea. The surface now holds as much freshwater as the Great Lakes and the gyre is spinning faster, still clockwise.
What will happen next? The past gives us a hint.
Thirty years ago, when the gyre reversed direction for an extra long time, its ice and cold freshwater caused the North Atlantic herring fisheries to collapse and plunged Northern Europe into a temporary deep freeze.
Will the Beaufort Gyre change direction soon? And how long it will spin counter-clockwise? No one knows. Will the change be benign? Probably not.
The globe is warming overall (hence it was called "Global Warming") but the resulting climate change is both hot and cold, weird and unpredictable.
It's a bit like watching chaos unfold.
Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world ...
-- The Second Coming by W. B.Yeats
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.
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.
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:
Before the storm: West Dennis Beach on the ocean side.
During the storm: Corporation Beach in the protected middle of the bay shore.
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.
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!
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.
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.
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!
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.
Though the ocean will never flood Pittsburgh, I'm still fascinated by the rising sea. (*)
Back in October I wrote about sea level fingerprints, the pattern of tiny elevation changes in sea level caused by uneven gravitational forces around the globe. The highest ocean peaks are in the tropics, the deepest valleys are near melting glaciers. As the land loses mass (ice) its gravitational pull decreases and it stops hugging the ocean to its shore. The water has to go somewhere so it goes to the tropics.
This means that glacial melt affects sea level rise in two ways: (1) It adds water to the ocean that used to be sequestered on land and (2) it alters the sea level fingerprint, lowering the ocean nearby and raising it far away.
If you do the complicated math, you can find out how individual melting glaciers will affect sea level at specific locations.
Last month, scientists at NASA Jet Propulsion Lab did just that when they published a paper in Science Advances and an online tool that illustrates how glaciers will affect 293 coastal cities. Let's take a look at Miami.
Almost half the sea level rise in Miami will be caused by glaciers (47.4% of total sea level rise) and almost half of that will be Greenland's fault (20% of total sea level rise). That's why Greenland is so red in the screenshot above.
The next highest glacial contributor in Miami will be Antarctica (12% of total sea level rise). In the screenshot below you can see that South American glaciers help, too.
In fact, the entire northern hemisphere is endangered by Antarctica's melting ice because it's so far away. Ironically the safest place to be is right next to a melting glacier. Sea level will go down at those sites.
(*) Pittsburgh's Point is 711 feet above sea level. My immediate family lives 10 to 25 feet above sea level in Virginia and Florida.
(screenshots of glacial contribution to sea level rise in Miami from the online tool at NASA Jet Propulsion Lab. On the first screenshot I added a pink circle to highlight Miami. Click on the images to use the online tool.)
You know things are strange when there's an outbreak of 15 tornadoes in Ohio and western Pennsylvania in November.
Just over a week ago, on Sunday November 5, 2017, a cold front passed over the southern Great Lakes and Ohio River Valley. Before the front arrived it was humid and around 70 degrees -- as much as 17 degrees above normal -- so the front's leading edge spawned 15 tornadoes.
The National Weather Service in Cleveland mapped 14 of them in their region. I've added the EF-1 tornado in Calcutta, Ohio just west of Beaver County, PA reported by the National Weather Service in Pittsburgh. Yes, 15 tornadoes!
The tornado in Williamsfield, Ashtabula County, Ohio was one of the strongest, an EF-2 with winds of 127 miles per hour. It cut a swath 7 miles long ending at the western shore of Pymatuning Lake. The damaged house shown above makes me glad I wasn't there!
This [Calcutta, Ohio tornado] is the 14th confirmed tornado so far this year in our county warning area. On average, we see five tornadoes a year. This is the first November tornado since 2003 /14 years/ in New Philadelphia, Ohio. This is the 5th tornado in November for Columbiana county since 1950.
Experts say that climate change increases the frequency of severe weather. I'd say that 15 tornadoes in November look like a good example.
Sometimes it's hard to imagine that we humans are part of the natural world. We think we are outside of Nature, instead we are intricately entwined. This special exhibit at the Carnegie Museum of Natural History shows how we affect Nature and are affected by it.
We Are Nature: Living in the Anthropocene tells many stories of our impact on Earth by focusing on five areas: pollution, extinction, PostNatural (intentionally altered organisms), climate change, and habitat alteration.
Some of our effects are so common we forget they wouldn't exist without us. Dogs, for example. They're in the PostNatural category.
We also tinker with wild things like wolves. The plaque below this animal says:
"A Trickle-Down Effect (Trophic Cascade): Humans eliminated gray wolves from Yellowstone National Park in the 1920s. In 1995, 31 gray wolves were reintroduced to the park from Canada; the wolf population is now considered stable. While some ranchers may not agree, the return of wolves to Yellowstone, coupled with other ecological factors, has had positive effects on biodiversity and the health of the park."
But most of our effects occur when we aren't paying attention.
Acid rain is a byproduct of burning coal to generate electricity. We had no idea this made a difference until we noticed that our downwind lakes were becoming acidic. More than a water problem, acid rain makes land snails scarce and causes declines in ovenbird breeding success. An exhibit of tiger snails says:
Tiger Snail + Acid Rain: Acid rain from human pollution harms some of Pennsylvania's smallest animals: tiger snails. ... Museum scientist Tim Pearce found that before 2000, the tiger snail was found in 53 Pennsylvania counties. After 2000, that number was cut by more than half.
There's one object in the room that's the perfect emblem of our aimless effect on earth -- a shopping cart coated in zebra mussels.
The shopping cart says, "Humans were here."
Humans manufactured something not found in nature.
The cart ended up in one of the Great Lakes through human negligence (it rolled) or purpose (dumped).
As it lay submerged zebra mussels attached themselves to the cart. Zebra mussels are an invasive species accidentally introduced to the Great Lakes in the 1980s. They got there on the bottoms of boats.
Without humans, nothing about this object would exist.
p.s. In the Post-Gazette I learned that this is the first exhibition about the Anthropocene in North America. (Go, Pittsburgh!) It will run for a year, include additional programming, and the museum plans to hire a curator of the Anthropocene in January.
Twenty-one years ago I attended my very first hawk watch on a spectacular golden eagle migration day -- 26 October 1996 at the Allegheny Front Hawk Watch.
Nowadays when I want to see a lot of golden eagles I visit the Allegheny Front in early November because that's when the eagles fly by. Is it my imagination or are the birds migrating later than they used to? A new study published last month in The Auk: Ornithological Advances confirms that raptors' autumn migration has shifted later.
The study, conducted by Hawk Mountain Sanctuary, analyzed hawk count data for 16 raptor species from 1985 to 2012 at 7 hawk watch sites in eastern North America: Hawk Mountain Sanctuary (Kempton, PA), Hawk Ridge (Duluth, MN), Holiday Beach (Ontario, Canada), Lighthouse Point (New Haven, CT), Montreal West Island (Québec, Canada), Mount Peter (Warwick, NY), and Waggoner's Gap (Landisburg, PA).
The 16 species included both long distance migrants traveling to South America such as broad-winged hawks, and short distance migrants that stay in North America such as sharp-shinned hawks and golden eagles. Each species adjusted its peak migration, but the delays were pronounced for short distance migrants.
To parse out the reason why raptors stay north longer, the study compared climate and air temperature data in the birds' breeding areas to the timing of migration during the 28 year period.
As you can see from this NOAA map from October 2012, the climate warmed in the breeding zone in eastern North America (marked with a yellow square). Click here to see the details on the study's map.
Because the warming climate delays the first frost, plants and insects remain abundant later in the year. This abundance ripples all the way up the food chain to raptors who postpone their fall departure. The study found that the shift in migration matches the pace of warming climate.
Golden eagles demonstrate the trend. Between 1985 and 2012 they waited an additional 0.16 days/year before moving south. By 2012, the delay was 4.48 days. Extrapolating to 2017, golden eagles are leaving 5.12 days later now than they did in 1985.
Whats' more than five days after October 26? November 1. So I'm going to the Allegheny Front Hawk Watch in November.
Click here to read about the study and download the full report.
p.s. Three species have delayed autumn migration even more than golden eagles: Sharp-shinned hawks added 0.2 days/year, northern goshawks added 0.21 days/year and black vultures added 0.40/year.