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.
But we aren't on the bloom map yet.
When will our wildflowers bloom? We'll have to wait and see.
* 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').
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.
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.
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.
The Allegheny is flooding, too, at the 10th Street Bypass.
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!
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.
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!
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.
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.