Mild November: Open water in December?

Posted at 4:07 PM on November 17, 2009 by Paul Huttner (6 Comments)

Ice free shoreline soaking up November sun on St. Louis Bay in Lake Minnetonka. (Photos by Paul Huttner)

Things are beginning to look a little odd in Minnesota these days.

This is the week when we would expect to see snow cover blanketing the ground in the Twin Cities. Our average date for the first inch of snow cover is November 21st. That's Saturday folks. No sign that will happen this year. In fact we could be pushing 50 again this weekend.

While springtime "ice-out" data is abundant in Minnesota, ice "freeze-up" data is sparse and hard to come by for Minnesota lakes. Maybe we're all a bit in denial when our favorite lake freezes over.

Still I can remember many years when I was skating (foolishly perhaps) on smaller bays in Lake Minnetonka by Thanksgiving weekend. I would say it is quite common to start seeing the first ice forming on ponds and small lakes and bays by this week. And I've seen many years with Lake Minnetonka covered with ice by the first week of December.

Late season boater out for a mid-November ride on Lake Minnetonka.

So far this year there is not a hint of ice on any area lakes or ponds. In fact, I believe all lakes in Minnesota are ice free as of today. And if you look at the GOES 1km visible satellite image below you can see it appears that lakes are ice free well north into Ontario.

College of DuPage visible satellite image form today shows lakes in northern Minnesota and southern Ontario largely ice-free on November 17th.

The medium-range forecast maps do show a cooling trend in the next two weeks. This should bring down enough cold air to freeze up some ponds and small bays by around the first of December. Still, there are indications of periodic warm spells. That might keep the big water open for several weeks to come. That would mean open water is possible on large Minnesota lakes well into December. There is evidence that supports a climate shift induced trend toward later ice-in and earlier ice-out sates in Minnesota.

It's said there really is no bad weather, just different kinds of good weather. Most of us are enjoying our balmy November. The ice fishing crowd? Not so much.

PH

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Comments (6)

Hi Paul,

As always, Updraft is a great read!

I wanted to put out there that it appears as though Thanksgiving Day temperatures for the last 10 years, and those proposed for 2009, adhere pretty closely to historical temperature readings...it appears that it's about half and half for snow on Thanksgiving Day as well.

http://climate.umn.edu/doc/journal/thanks0811.htm

Regards,

-jlk

Posted by Josh | November 17, 2009 10:16 PM

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JLK-

Looking at the website you just linked to, the average Thanksgiving high over this period of record (1891 - 2007) is 33.7 degrees F, while the average high for the last 10 years of record (98-07) is 40.5 F. The projected high for this Thanksgiving is high 30's, so somewhere in between, but still above the historical average.

Posted by Nathan | November 18, 2009 8:15 AM

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These kinds of "now" vs. "then" averages depend on where you start your model. There are several periods warmer than the "historical average" if you select randomly beginning with an above-average temp.

To take an arbitrary set of dates, between 1891-1921, high temperatures on Thanksgiving Day were below freezing 11 times, less than half the time. Between 1906-1918, 12 of 12 years had temps above freezing.

Posted by Josh | November 18, 2009 8:39 AM

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Just wanted to clarify my comments above:

I'm not trying to "prove" anything here. I'm genuinely curious!

So, Nathan arrives at an average temp of 40.5 degrees by adding up the the high temperatures from 1998 to 2007 and diving by 10. However, using the same methodology and randomly selecting a 10 year period beginning with a high temp - say, 1914-1924 - we arrive at an average high 42.7, well above the historical average of 33.7.

Now, this perhaps a crude way of doing things, but it shows that where one starts his model is important. Using 1998 - the year of the super El Nino - as a starting point is going to skew the results.

It would appear that a cursory glance at T-Day temp readings show a pretty equal probability of being above or below the "average" temp.

And, yes, I need a new hobby. =)

Posted by Josh | November 18, 2009 10:47 AM

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One Thanksgiving in the not-too-distant past was like hardcore winter. The HIGH here in Duluth was only 5 above, with a morning low of 15 below. Snow depth was 8".

Posted by Mark | November 18, 2009 5:13 PM

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Sorry. Forgot to give the date of that frigid Thanksgiving: November 28, 1985.

Posted by Mark | November 18, 2009 5:29 PM

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