THE ROBINS ARE BACK, IS SPRING!
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THE ROBINS ARE BACK...
As has been her habit for many years, my mother Rose Marie, gets very excited about the return of the robins each spring. She's 94, and she doesn't need to see them, she hears the first flap of their wings. As soon as she spots the first one, she's on the phone to me with the (breaking news). Boy child, she says, "spring is about to spring"! Well, I got the call Sunday, so at least in Coralville, Iowa the orange breasted song birds are back and singing their hearts out.
I did a bit of research about what causes them to make their northward migration. What I found was pretty interesting in that they tend to follow the 37-degree average daily isotherm. Migratory restlessness builds up as sunlight increases. Scientists call this "zugunruhe," a German compound word consisting of Zug (move, migration) and Unruhe (anxiety, restlessness).
Robins fly at 30-36 mph and usually migrate during the day. They can fly for hours, so on days with good migrating conditions, they can cover 100–200 miles per day staying close to that 37 degree temperature line. The arrival of the first robins is a welcome sign of spring, because it is often closely tied to the appearance of the first earthworms. During winter, most earthworms stay in their underground burrows. They are prisoners in frozen soil under ice and snow. In the spring, earthworms move upward after the ground thaws. Earthworms travel only a few feet to the surface during their migration.
After tunneling upward. They appear at ground level, leaving the first castings of the new season, as soon as the average temperatures of the ground reaches about 36-37 degrees. As temperatures rise, watch for these tell tale signs of spring in your backyard. Which will appear first, a worm or a robin? Will they appear together when the average temperature reaches 37 degrees? It's kind of like the chicken and the egg, which came first? Sorry, that just randomly popped into my head.
The spring migratory flight depends entirely on weather, since they follow the 37-degree isotherm. For example, It can take anywhere from a few days to several weeks for a robin to go from Texas to Minnesota. High pressure systems with stable weather are best for migrating. In spring, robins follow surges of warm air. Moderate conditions are better than warm. Hot weather gets them overheated. Rain and snow are hard to migrate in. Ice rain and hail are much worse. They are grounded in tornadoes. Just like us, robins are pretty fickle about their weather conditions. I think this dude picked the wrong isotherm. Just a tad cold!
By the way, robins figure out their location on the planet in much the way sailors on the high seas once did--using the angle of the sun in relation to the time of day. If blown off course, they fly to where the sun will be at the proper angle. That's rather cool.
THAT 37 DEGREE ISOTHERM IS MOVING NORTH
Make no mistake about it, February is going out like a lamb. The EURO ensemble does not show a high temperature colder than 41 through March 5th in the Quad Cities. It also indicates 12 of the next 15 days will have highs of 50 or above. 3 days are in the low 60s.
The GFS is of a similar mindset, only warmer. 14 of the next 16 days are 50 or above, with 2 days shown at 71!
With regard to those 70 degree highs, I do think readings like that are attainable. I can't say with certainty, but I think the odds are better than 65%. Teleconnections certainly are leaning that way, with the AO (Arctic Oscillation) going negative. That seals off direct discharges of bitter cold Arctic air to the Midwest.
The EPO (Eastern Pacific Oscillation) is making a nice push to positive territory.
Note how the positive EPO produces warm temperatures over the lower 48.
Then there is the PNA (Pacific North America Oscillation). It's diving into negative territory, which is a big deal if it happens as it flips the trough from the eastern U.S. to the west.
That puts us in unseasonably warm southwest flow with lots of warm air and potentially abundant moisture. This is the jet shown March 4th.
Check out these temperature departures on the EURO for March 5th.
I would also add that this is a classic looking set-up for early season thunderstorms and potentially even severe weather somewhere in the Midwest. The last 2 years, Iowa has had tornado outbreaks in March that have produced EF4 tornadoes. It's quite unusual to see those big bruisers in March. 3 consecutive years with a tornado outbreak is unheard of. I clearly have no idea how this plays out since so many mesoscale features have to come together, but on paper, that's what you expect to see. This is just one run, so don't lose any sleep on my speculation 2 weeks in advance. It did stand out!
One more reason I'm bullish on the warm-up is that there is a very significant stratospheric warming going on near the pole. Preceding that, it's common for a surge of warmth in the 2-3 week period.
I should also caution that strat. warms often force Arctic air into the mid-latitudes in 3–4 weeks. It would not be shocking to see a blast of cold air sometime in mid-March. Something to keep an eye on.
Meantime, we continue to warm, staying generally dry the next 7–8 days. Highs may reach 60+ in spots Wednesday. Towards the end of the week there will be a buckle allowing NW component to the upper level flow. That should cool us some, but how much depends on how deep the cold air digs. At least for now, it's just a glancing blow, and we start another warm-up by the end of the weekend. Alright, go find yourself a worm or a Robin, spring is lurking. Roll weather...TS P.S. With my recent health issues, I very much need to reach my fund-raising goals. To keep things as they are, I'm in humble need of your donation to the site more than ever. If you use it and find value in it, please consider a contribution. Thanks to you who have already helped the cause!
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