Friday Sprog Blogging: Groundhog’s Day 2007

Last night, while tucking the Free-Ride offspring into bed:
Dr. Free-Ride: Tomorrow is Groundhog’s Day.
Elder offspring: I really hope the groundhog doesn’t see his shadow this year so we can have an early spring.
Younger offspring: Yay! Spring could start tomorrow!
Dr. Free-Ride: Hold on now, “early spring” doesn’t mean spring will start immediately, it means —
Younger offspring: I really want spring to start early because then my birthday will come sooner!
Dr. Free-Ride: OK, you guys realize that what the groundhog sees has no impact whatsoever on how many calendar days are left until May, don’t you?
Elder offspring: Not at bedtime we don’t.
* * * * *


This morning, when the sprogs were a little more rational:
Dr. Free-Ride: I remember last year you had some doubts about how useful it was to use the groundhog as a way to predict when we’ll get spring weather.
Elder offspring: Yeah, but people seem to have fun seeing what the groundhog will do.
Dr. Free-Ride: Remind me how this works. If the groundhog sees his shadow?
Elder offspring: Six more weeks of winter.
Dr. Free-Ride: So that would put the start of spring at March 16. (My calendar actually puts it at March 21.)
Elder offspring: And if the groundhog doesn’t see his shadow, we’re supposed to get an early spring.
Dr. Free-Ride: What’s early?
Elder offspring: Huh?
Dr. Free-Ride: By what date would you want definite spring weather in order to officially call it “early spring”?
Elder offspring: Somewhere between Febraury 20 and February 27, I think.
Dr. Free-Ride: That would work for me. OK, what kind of weather would you need to see to say, “Yes, that’s no longer winter weather, that’s definitely spring”?
Elder offspring: Hmm. Maybe the same amount of rain as sun?
Younger offspring: But here, winter weather is rainy.
Elder offspring: Average temperatures that are higher than January temperatures.
Dr. Free-Ride: After this January, that won’t be hard.
Elder offspring: I know! Spring starts when there’s the same amount of daytime as nighttime.
Dr. Free-Ride: Yes, it’s true that at the Spring Equinox day and night are the same length. But the way things are set up now, that shouldn’t be drifting way back to February.
Younger offspring: Why not?
Dr. Free-Ride: That’s why we have leap days about every four years. It takes the earth a bit longer than 365 days to get all the way around the sun, so we get an extra day in February every now and then so that the Spring Equinox keeps happening around March 21. Otherwise, the seasons and the calendar would get out of sync.
Elder offspring: But the spring weather isn’t totally in sync with the Equinox, then.
Younger offspring: (looking out the window at overcast skies) It’s pretty cloudy. I don’t think the groundhog’s going to see his shadow.
Dr. Free-Ride: Child, the canonical groundhog is in Pennsylvania.
Elder offspring: We should get on the computer to find out the weather in Pennsylvania.
* * * * *
Official word from Punxsutawney Phil: expect an early spring.
A commenter last year suggests that the groundhog/shadow predictive model may actually be a not-entirely-silly way to get a handle on Rossby waves, which are related to the movement of warm and cold air masses that, naturally, are tied into the whole winter weather/spring weather power struggle.
I’m still of the view that there are better ways to forecast the weather than the groundhog.

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Posted in Kids and science.

2 Comments

  1. February 2 is also the Christian feast of Candlemas, the Feast of the Purification of the Virgin (alternatively, of the Presentation of Jesus in the Temple). In Jewish law, a woman who has borne a son is considered impure for forty days and then goes through a ritual purification, so Mary brings Jesus to the temple and offers up a sacrifice. In addition, the beginning of February is about half way from the winter solstice to the equinox, a moment when the lengthening light has become distinctly noticeable (in northern regions, of course), and so a time of fertility rituals. Surely the groundhog tradition, as well as the candle-blessing of Candlemas, is related to this change in light. This year the Jewish New Year for Trees, Tu b’Shevat, coincides closely, and that coincidence (since Tu b’Shevat is by definition the fifteenth day of the [lunar] month of Shevat) also brings us a full moon. It’s like a judeo-christian-pagan-astronomical Bingo.

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