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Nature's variability

Posted at 1:22 PM on February 21, 2011 by Craig Edwards (7 Comments)

Here is a great example of the challenges of pinpointing snow accumulations. When the snow is blowing and you mix in very strong dynamics that produce updrafts violent enough to trigger lightning and thunder you get a dramatic variability in snowfall measurements.

For instance, at the weather lab in Eden Praire I measured twevle inches. Yet another report from Eden Priarie was as much as a foot and a half.

snowfallfeb20.jpg
Graphic courtesy of the NWS in Chanhassen. Totals as of 9AM.

Lots of moisture has been laid downed in the Minnesota River Valley. Hydrologists will soon say all bets are off on how high the rivers will rise in the next month or so.
CE

Comments (7)

Paul or Craig, How did the models miss all the dry air that interfered with the snow? Even the model runs after the snow started seemed not to take it into account.

Posted by Don | February 21, 2011 2:49 PM

I would surmise the sampling spacing of the upper air sites, i.e, Chanhassen to International Falls to Green Bay, allows for considerable interpolation of moisture fields. The vertical profile is only sampled with radiosondes twice daily. The model smooths this data, with some input from satellite sensing and radar returns.

Many meteorologists were alittle nervous when the snow was evaporating in the north Metro on Satuday afternoon. The late start held down snow amounts as shown on the graphic.

You could summarize it as micro-meteorology, or the mesoscale anaylysis.

Posted by Craig | February 21, 2011 3:12 PM

That's all well and good, Craig, but how about some helpful information like:

When will it stop snowing today?

What's the 10 day forecast look like for temperatures?

You discuss the awfulness of our winter weather endlessly, but how about some information about when this stalag of winter will actually end?

Posted by Luke | February 21, 2011 3:20 PM

Let's hope it doesn't stop snowing for a while. Alpine and telemark skiing during the storm yesterday was great, with our tracks being filled in within 30 minutes or so. A rare treat in the Midwest, and one that I hope doesn't end for another month or so.

Posted by Mark Weinberger | February 21, 2011 3:55 PM

funny you should ask Luke, I have the outlook for the first week of March coming right up. More of the same.

Later this week the NWS outlook for the spring will be issued. Stay tuned for that.
CE

Posted by Craig | February 21, 2011 3:56 PM

Do you have a breakdown of the snow totals comparing yesterday with today? Here in Mahtomedi, we have had a steadier snow with larger flakes today than yesterday. I would expect at least 1/2 of our snow has come today since Monday morning. A lot of people are surprised as they cleaned off their driveways only to find them buried again forcing them to park on the street after going out.

Posted by Dan | February 21, 2011 4:07 PM

Dan, I'll post a link on the updraft about 6pm that should give the latest snowfall totals as reported to the NWS in Chanhassen. The forecast called for an additional two to four inches today. Did you pick up about three inches today?

Posted by Craig | February 21, 2011 4:26 PM

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