Winter finally here to stay; weekend snow likely

The season formerly know as winter has finally arrived in Minnesota.

Biting winds. Dancing snowflakes. Frozen lakes. Remember?

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Skating on Lake Minnetonka in December 2013. Paul Huttner/MPR News.

The dominant northern hemisphere upper air pattern for the past several months has now shifted to what meteorologists call 'northwest flow' across North America. This atmospheric vehicle for efficient cold air delivery to the USA looks to stay locked in until at least December 20th.

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NOAA

First consistently colder than average spell in 15 months

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Our dramatically colder weather shift represents the first consistently colder than average streak in over a year. We've just lived through 15 consecutive warmer than average months in the Twin Cities, and the warmest fall on record in Minnesota.

The streak ends in December if current forecasts of significantly colder than average temperatures verify.

The first 6 days of December ran +8.3 degrees vs. average in the Twin Cities. Vaya con dios, baby.

First sub-zero temps of winter

Minnesota rides the edge of a bitterly cold air mass for the foreseeable future. Temps plunge into the -20s in the Red River Valley this weekend. If the Twin Cities picks up some snow cover this weekend as expected, the season's first sub-zero temps likely arrive in the metro by next Monday and Tuesday morning.

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NOAA GFS model 2-meter temps via tropicaltidbits.com

Weekend Clipper: Snow on the way

It seems a little weird to feel the bite of single-digit wind chills with nearly green grass outside. That should change in the Twin Cities and southern Minnesota this weekend.

Forecast models are tracking a Clipper that should bring the season's first 'semi-permanent' snow cover Saturday.

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NOAA GFS model surface map via tropicaltidbits.com

The most likely track of the surface low at this point lays the heaviest snow band out south of the metro. The zone between the Minnesota River and the I-90 corridor is most favored for the heaviest snow axis.

Several inches of plowable snow could fall in southern Minnesota Saturday into Saturday night. It's still too early to put high confidence in snowfall totals, but 3" to 6"+ seems quite possible for southern Minnesota, with a 2" to 4" range a reasonable notion for the Twin Cities. At this point heavier snowfall totals would seem to favor the south metro.

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NOAA GFS model snowfall forecast via tropicaltidbits.com

Stay tuned for track and snowfall updates as we head toward the weekend.

Weather a factor in Pearl Harbor attack

Many of us have heard how a good weather forecast helped make the allied D-Day landing on France possible. But did you know that an accurate weather forecast by a Japanese meteorologist also aided the Japanese surprise attack on Pearl Harbor?

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The USS Arizona (BB-39) burning after the Japanese attack on Pearl Harbor - NARA -

Here's a deeper look into the forecast and conditions at Pearl Harbor from meteorologist Paul Gross at WDIV-TV in Detroit.

How did the Japanese navy manage to secretly maneuver into position to attack our naval air station in Hawaii?  Because of a really good weather forecast by Hidetosi Arakawa, a Japanese meteorologist who gave his navy a weather forecast on November 26th, 1941, with no knowledge of what the forecast was for. On that day, the Japanese began a twelve-day trip across the Alyshan Sea, in cloudy, misty weather. Low, thick cloud cover extended over a large area, which was perfect for hiding the huge attack fleet from reconnaissance aircraft.  And hide they did…refueling whenever calm seas presented an opportunity. On December 2nd, Admiral Yamamoto gave the command from his flagship to execute the attack plan.  His message was “Niita Kayama Nobore,” which means “Climb Mount Niitaka.” This was the code phrase indicating “proceed with attack.”

When they reached their intended destination, about 200 miles north of Hawaii, on December 4th, they wrestled to come up with a way to fly their attack planes toward Hawaii above the clouds, where they wouldn’t be seen.  However, in order for the mission to succeed, they needed clearing so they could see their targets. How would they possibly know if weather conditions at Pearl Harbor would permit operations? The answer to this question will surprise you: by listening to a radio! As they struggled to listen to a Honolulu radio station, they accidentally heard the disc jockey talk about the weather forecast. The announcer said “averaging partly cloudy, with clouds mostly over the mountains.” This was all the Japanese needed to know, and planes were ordered to depart their aircraft carriers and head to Pearl Harbor…360 planes in all.

Weather Channel to Breitbart: "Stop Using Our Video to Mislead Americans"

The record off the charts global warmth of the past 3 years is unprecedented on the modern climate record. It's the first time we've recorded 3 consecutive 'warmest years on record' going back to 1880. The last cooler than average year globally? 1976.

The background forcing of climate change and the strongest El Nino on record both played a role in the unprecedented global warm spike the last 3 years. Climate scientists fully expected a slight drop in global temps late this year into 2017 as El Nino fades, but nothing even close to large enough to produce the first cooler than average year globally since 1976. In short, even with the expected year to year variations climate change continues to drive global temperature higher in the long term.

That didn't stop fake news and climate denier websites from spewing misleading headlines about global temperatures. The Weather Channel took exception when anti-climate change biased Breitbart used some of their video in a shoddy misleading post.

The war on science has arrived. News buyer beware as we enter the era of fake news.