Pine Tree Effect; Snowy Friday; Excellent “Arctic” air quality

Sub-Zero Start

We ran out of degrees again in Minnesota this morning.

Another sub-zero start greets us this winter, leaving no doubt this is still Minnesota…and it is still February.

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10.9″ snow so far in February? The snowiest month in 2 years? More snow on the way? Yeah, yep & yup.

In this edition of Updraft we count up the negative numbers, look ahead to the next snowfall and tout a surprising benefit of really cold arctic air.

And the fresh snow should lead to an excellent forecast for the Birkebeiner” ski race on Saturday.

Am I reaching a bit here for “silver linings?”

Absolutely!

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-3F at MSP Airport this morning

-9F in Eden Prairie

-11F in Lakeville

-27F in Crane Lake

12 days at or below zero at MSP so far this winter (including Wednesday AM)

3 sub-zero days last winter

23 sub-zero days in an “average” winter (1981-2010 data)

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Snow Train Keeps Rolling:

It’s snowed at least a trace 14 of 19 days so far in February at MSP. Why stop now? The weather hit’s just keep on comin’ this week. Friday’s snow system will mark the 8th to visit southern Minnesota this month.

It’s a great recipe for snow. 1 part cold air, 1 active jet stream overhead. Now as the jet stream turns into the southwest, we can and a good splash of Gulf Moisture.

This latest system is a “Panhandle Hooker” that will wind up in Oklahoma Panhandle early Thursday, then shoot northeast into Iowa.

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Overnight model trends continue the theme of slightly less snowfall from Tuesday’s runs.

The Euro & GFS have backed off to around 3″ to 4″

The NAM continues to be the most aggressive with up to 7″ with a good 18 hours of snow starting between 9pm & midnight Thursday night… to 7pm Friday evening.

Right now 3″ to 6″…maybe 7″ looks like a pretty good metro range, but keep in mind the models are likely to change again. It still looks very likely we’ll be shoveling and dealing with snowy commutes by Friday morning.

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NAM most agressive on Friday snowfall

Image: wxcaster.com

I still think the heaviest totals…a good 6″ to 8″+ will fall along the I-90 Corridor in southern Minnesota.

Yesterday on All Things Considered with Tom Crann I chatted with Tom about the early posting of winter storm watches…almost 60 hours in advance of the incoming system.

Here’s an interesting excerpt from the Twin Cities regarding the conundrum of meeting “warning criteria” with this system, and the likely advisories that will be issued.

THE IMPACTS OF THE WEAKENING SYSTEM WILL RESULT IN THE GREATEST SNOW TOTALS ACROSS THE SOUTH…WHILE THE SE SHIFT RESULTED IN A DECREASE IN THE SNOW TOTALS NORTHWEST. WITH THIS FORECAST…ENDED UP WITH 6 TO 8 INCHES ACROSS SOUTH CENTRAL MN…4 TO 6 INCHES FROM SW MN THROUGH EC MN INTO WRN WI…AND 2 TO 4 INCHES FROM WEST CENTRAL INTO CENTRAL MN. INTERESTINGLY…THIS IS VERY CLOSE TO THE MEDIAN SNOWFALL TOTALS FROM THE CIPS GUIDANCE BASED ON THE 60 HOUR NAM FORECAST.

AS FOR HEADLINE IMPLICATIONS…TIMING CONSTRAINTS WILL LIKELY LIMIT HOW MUCH OF THE AREA WILL ACTUALLY MEET WARNING CRITERIA. FOR A WARNING…6 INCHES OF SNOW IS NEEDED IN 12 HOURS OR 8 INCHES IN 24 HOURS. AT THE MOMENT…THE ONLY PLACE THAT THESE TOTALS ARE MET WITHIN THE TIME LIMIT IS SOUTH CENTRAL MN…WITH THE 6 INCH AMOUNTS SEEN FARTHER NORTHEAST TAKING A LONG TIME TO GET THERE. FOR EXAMPLE…EAU CLAIRE HAS A TOTAL OF 6.1 INCHES OF SNOW FORECAST…BUT IT TAKES 30 HOURS TO GET THERE! AS A RESULT…AT THE MOMENT…IS LOOKING LIKE MUCH OF THE WATCH WILL END UP AS AN ADVISORY…WITH HIGHEST LIKELIHOOD FOR A WARNING BEING ACROSS SOUTH CENTRAL MN.

Winter Storm watches and warnings cover a lot of real estate in the central USA.

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Tired of snow but want a silver lining? The good news is for once the heaviest snow will fall on the hardest hit drought areas of Kansas, Nebraska and western Iowa.

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It may not help frozen soils much, but a foot of heavy snow is a plus for spring runoff and boosting river levels. Will it bust the deepest drought in decades? No…but every storm helps…and this will be a good step in the right direction.

Some of the heaviest snow will fall west of Omaha, where a cool foot is likely by Friday.

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One element that’s missing from this system for Minnesota is a good supply of bitter air coming in behind the system. Since the upper winds will quickly return to southwest behind the storm, there isn’t a good dose of cold air to “spin-up” and deepen the system over Minnesota.

Models easing a little:

Tuesday’s model runs suggested a trend of easing back on snowfall just a bit. That said, it still looks like we’ll get a good dose of snow in the metro and southern Minnesota late Thursday night and Friday.

The latest model runs suggest a general area of “plowable” 3″ to 6″ totals around the metro, with a better chance of 4″ to 8″ in southern Minnesota along the I-90 corridor.

It’s still fairly early so stay tuned as we tweak the numbers based on Wednesday & early Thursday model runs.

A second system looks to bring more snow Monday & Tuesday. In total I could easily see 5″ to 10″ of additional February snowfall for the metro and southern Minnesota between the 2 systems by next Tuesday.

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Image: Iowa State Univeristy

With 31.3″ so far this season…we could be close to 40″ of snowfall…and near our seasonal “average” snowfall by next Tuesday in the metro.

Don’t look now but this is turning into the “real” winter of 2012-’13.

Fresh Yukon Breezes:

The “Minnesota hunch” is back these days. Your neighbors walk around hunched over to ward off the cold. (Does that really work anyway?)

But one surprising aspect of the is cold arctic air is that it is remarkably “clean.”

Check out Tuesday’s AQI readings from the MPCA.

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I can’t recall the last time I saw a “zero” reading in Minnesota. Brainerd had “perfect” air quality Tuesday.

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You could clearly see the “crisp” outline of the Minneapolis skyline Tuesday coming over the “Ridgedale bump” on I-394 eastbound into the Cities.

With very few pollution sources between here and the Arctic Circle in the Yukon, this is some of the cleanest air we get in Minnesota.

And hey, no mosquitoes.

Pine Tree Effect:

It’s getting to be that time of year when deep snow cover reflects sunlight in western Minnesota, and dark pine trees bounce and scatter sunlight to warm the air more efficiently in forested areas in the east and up north.

Ever wonder why the Iron Range can be warmer in the afternoon than Fargo some days?

Here’s my explanation of how the “Pine Tree Effect” works.

PH

Enjoy!

  • John

    This is fantastic information – thank you! I’m driving from Minneapolis to the central Rockies in Colorado on Friday. I’ve been considering two routes:

    1) Head out to Rapid City, South Dakota on I-90, then skirt south around the Black Hills and through the southeast corner of Wyoming through Cheyenne, before dropping into Colorado on I-25.

    2) Going south to Des Moines, Iowa, then turning west and crossing Nebraska on I-80, and then through Colorado on I-75.

    Based on your excellent post above, it looks like option 1 is the best choice, even if it is a longer drive. I’d really appreciate any insights that you might be able to share. Thanks again for the information!

  • Mark

    I see that Duluth is in the dark blue 6″-8″ category on the snowfall forecast map. That must mean strong east-northeast winds bringing in a lot of lake effect snow? It doesn’t happen often, but when it does, we really get hit.