Monday, February 2, 2015

Official 2015 Twin Cities Groundhog's Day Report

Posted by Kirk
The 2015 Report:

What a difference a year makes!

On Groundhog's Day 2014 we'd just pulled though yet another "Polar Vortex" and there were high snowdrifts everywhere. Here we are today and solid snow cover is hard to find anywhere in the Twin Cities.

Last year I took a new job at Lowry Nature Center in the west metro after a 12 year stint at Warner Nature Center in the east metro. This means that last year I missed out on seeing my old pal "Stuff Stanley" the groundhog of record for many of the Official Twin Cities Groundhog reports over the years. I decided this year to pay an early morning visit to Stanley to see if he saw his shadow. Did he? You'll have to watch the video to find out!

The official Twin Cities Groundhog Prediction:
Just like last year, the groundhog DID see his shadow in the Twin Cities so we have six more weeks of winter to look forward to. That's the story anyhow. Last year we had a huge warm-up right after Groundhog's day that saw us flirting with 50 degrees before plunging down again at the end of the month. This year could be a bit of the same. While the forecast calls for a few days near zero this week the longer range forecasts are looking at us going up near 40 degrees again. 

Personally I'm going to have to predict against the groundhog this year. We have very little snowfall and a warm spell in the 40s could melt what we do have away. Once the ground is exposed, the longer days and more direct sunlight we're getting are going to help warm up the ground and create  more warm days than cold days all things being the same. 

That's my personal prediction, we'll see who's right, me or a stuffed groundhog.


What's the connection between Groundhogs, shadows and the seasons?

The connection is tenuous at best. Further south than Minnesota, male groundhogs do come out of hibernation early to scope out and check on their breeding territory. In Minnesota, February 2nd is usually too early for this to happen. Seeing the first groundhogs checking out their territory is surely a sign of spring though. Okay, but what does seeing a shadow have to do with it? The connection to shadows has to do with prevailing weather patterns. We often associate sunny days with warmth and the coming spring but sunny days in the winter aren't always warm. Clear winter days are often the result of cold Canadian air that has settled over the state. A shadow in the winter often means we're in a pattern of cold air flowing south. It can take many weeks to break that pattern and warm the area. All of the snow we have will also keep us cold longer.

Celestially, February 2nd is an important day. According to the solar calendar, it should mark the end of winter and the beginning of spring.

Forty-two days ago was the winter solstice, the day of the year when we have the least sunlight. From that day on, the amount of daylight increases until the day when there are equal amounts of night and day. We call this day the equinox and it falls around March 21st. February 2nd falls half way between the solstice and the equinox so in theory it should mark the end of winter and the beginning of spring.

Has anyone seen any crocus flowers blooming?

Obviously the winter solstice is not really mid-winter. Why do we call the solstice mid-winter if it is really more like the day winter begins? This has long been a puzzle and even caused a few arguments between astronomers and meteorologists. The answer is something we call the lag of the seasons and it affects Groundhog’s day as well. Yes, it is true that Groundhog’s day technically marks the beginning of spring from a celestial point of view but our experience tells us otherwise. Our seasons lag behind what the sun tells us in the sky.

Saying spring starts on Groundhog’s day is a little like saying a frozen dinner is ready to eat as soon as it is pulled out of the freezer. The northern hemisphere has been cooling down for months by the time the solstice arrives. Forty-two days with just less than a minute more sunlight each day is not enough to thaw out the frozen landscape into a lush vernal garden.

The established pattern of cold weather continues for many weeks after the beginning of the increase in daylight. This lag makes it seem like mid-winter actually falls on Groundhog’s day rather than the solstice. Rest assured though that on Groundhog’s day, even if it feels like the middle of winter, we are getting an hour and seven minutes more daylight today than we did just forty-two days earlier.

Groundhog’s Day may marks the beginning of spring according to the sun but it will be about forty-two more days until we feel the change enough to call it spring. It may seem like winter has a grip on the land but the sun has been working hard to reverse the trend for over a month and we’ll soon start to see those effects.

Incidentally, the legend tells us that if the groundhog sees its shadow it will be scared back into the den and we’ll have six more weeks of winter. Why six weeks? How many days are there in six weeks? Forty-two. Six weeks takes us exactly to the spring equinox.