Watching Thanksgiving glaze ice and snow potential

First the good news.

Travel looks good today across most of Minnesota and the Upper Midwest. Life on the mild side of our inbound weather system is easy today. We top out in the mid to upper 40s across most of southern and eastern Minnesota.

Heading to Omaha, Neb., Des Moines, Iowa, or Chicago today? You'll enjoy a balmy 50 degrees this afternoon.

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NOAA

Wintry Thanksgiving Day mix

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One thing meteorologists factor in to the forecast is timing and impact of any given weather event. Take the first snow of the season, throw in a holiday, and the impact is magnified.

An inch or two of snow in late January? Barely a blip on your local newscast. A light icy glaze with an inch or two on Thanksgiving and the first measurable snow of the year? Somebody alert the media.

Factor that into your Thanksgiving travel plans tomorrow. This system won't be a big deal by Minnesota winter standards, but even a light icy/snowy coating can create a few travel issues this time of year. That's especially true on untreated roadways early in the winter driving season.

As the cold front slides through Minnesota overnight tonight, patchy light rain and drizzle change over to a light icy glaze then some sleet and snow Thanksgiving Day. I could see a nice little burst of moderate snow for a couple of hours from the metro southeast Thanksgiving day.

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NOAA

The highest travel impacts Thanksgiving Day will be from the southern Twin Cities south and east. If you are planning travel along Interstate 35 south to Albert Lea, Minn., and Des Moines, Highway 52 toward Rochester, and Interstate 94 east into Wisconsin expect some light icy glaze and some snow covered roads Thanksgiving Day.

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Here's another view from the La Crosse, Wis., National Weather Service

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Here's the view from Duluth if you are heading north.

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And here's  the picture for Sioux Falls, S.D., and northwest Iowa if you are heading west Thanksgiving Day.

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Bottom line: Expect a wintry mix of precipitation Thanksgiving Day. The storm wont be a big deal by Minnesota winter standards, but it will produce some moderate Thanksgiving travel issues.

Black Friday chill

That spring in your step early Friday morning could be the latest door buster deal on a huge flat screen. Or, it could be your car thermometer flashing 18 degrees. Black Friday looks dry and sunny but chilly. Temperatures mellow by Sunday afternoon. The back half of the Thanksgiving weekend looks good for travel. The next chance for snowflakes arrives Monday and Tuesday.

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Weatherspark - NOAA GFS data

Balmy December?

Looking ahead into December, I still see occasional gushes of mild Pacific air streaming east into Minnesota. The National Oceanic and Atmospheric Administration's Global Forecast System has consistently cranked out a milder Pacific air mass in the days surrounding Dec. 10.

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NOAA via IPS Meteostar

Temps pushing 40 degrees and little or now snow cover well into December? It seems to be a growing possibility, and fits with my seasonal assessment of our likely El Nino driven mild winter pattern. NOAA's Climate Forecast System (CFSv2) continues to crank out temperatures as much as 4C or more than 7F warmer than average for December across Canada and the northern US.

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NOAA

So far I see no reason to disagree. Even Judah Cohen, the father of the 'extensive Siberian snow cover = colder than average winter in the eastern U.S. hypothesis' seems to be tempering his winter forecast in deference to what looks like the strongest El Nino on record. (Bold text is my highlight.)

Looking longer term towards the winter, we follow Siberian October snow cover extent, Barents-Kara sea ice extent and tropospheric precursors to try to predict the winter mean AO state.

October Eurasian snow cover extent was above normal.  Following above normal snow cover, we expect a northwestward strengthening of the Siberian high coupled with a deepening Aleutian low.  The Siberian high has strengthened to the north but is somewhat displaced eastwards than is typical.

Arctic sea ice in the Barents Kara seas is below normal and certainly less extensive than last year at this time.  The persistent below normal sea ice in this region should help to build the Siberian further westward with time.  That coupled with a strengthening Aleutian Low, typical of El Niño winters should set up an atmospheric pattern that is favorable for increased energy transfer from the troposphere to the stratosphere that eventually warms the polar stratosphere and weakens the polar vortex and helps force a negative AO.

However if the energy transfer is not sufficiently strong over the next month to weaken the polar vortex, then the AO is likely to average positive in the mean and a mild weather pattern will dominate the mid-latitude continents this upcoming winter. 

This is especially true across North America where an El Niño driven southern Jet Stream will flood North America with mild Pacific air.

Stay tuned.