Check this out Minnesota. You just lived through the warmest fall on record.

For the autumn season (September through November) it was the warmest in state history dating back to 1895. On a statewide basis the mean temperature for the 3-month period was about 6 degrees F above normal. For the first 11 months of 2016, it has been the 2nd warmest in state history, surpassed only by 2012. – Mark Seeley Weather Talk – Friday December 2, 2016

Winter: Better late than never?

December opens on yet another mild note. Temperatures run 5 to 10 degrees warmer than average through Monday. Afternoon highs push 40 degrees in the Twin Cities and southern Minnesota again Sunday and Monday.

True December-like cold surges south on frigid northwest winds Tuesday. Single digit cold arrives by Wednesday morning.

National Oceanic and Atmospheric Administration Global Forecast System model 2-meter temperatures, via tropicaltidbits.com

The season’s coldest air mass so far plunges south next week as the jet stream buckles driving a cold pool over Minnesota.

NOAA

Alaska cold

The upstream air mass is finally looking bitterly cold across Alaska and the Yukon. Temps push -50 F in the Alaskan interior next week.

NOAA GFS model 2-meter temperatures, via tropicaltidbits.com

That air mass will modify before reaching Minnesota, but the available cold pool is impressive.

Cold? Yes. Snow? Not so much

I’ve been cautiously talking about chances for snow next week. Why are we so cautious about possible storm tracks and snowfall totals a week out? No meteorologist wants to be ‘that guy’ who forecasts a foot of snow 7 days out and ends up having to apologize to readers. But some do anyway. Thanks for the real boost to our credibility as a profession.

The truth? The state of the science of meteorology can’t pin down storm tracks a week out. Even 2 days out is still a challenge. The winter storm ‘pachinko ball’ can bounce a lot of different directions in 7 days.

A few minor snow showers clip Minnesota Sunday and Tuesday. All major forecast models have pushed next week’s potential snow-maker well south of Minnesota. A persistently cold, but dry northwest flows kicks in next week.

NOAA GFS model, via tropicaltidbits.com

Here’s the visual quick look forecast into next week.

Twin Cities National Weather Service

Tornado swarms increasing

The numbers say big tornado outbreaks are happening with increasing frequency. USA Today highlights a recent study in the journal Science.

NOAA, via Steve Grabman/NWS

The killers are coming in bigger and bigger swarms. The number of twisters in extreme, multi-tornado outbreaks, like the one that killed five people in the South earlier this week, are increasing. And scientists aren’t exactly sure why.

Since the mid-1960s, the number of tornadoes in big outbreaks has doubled, according to a study published Thursday in the peer-reviewed journal Science. A big outbreak in 1965, for example, would have contained 40 tornadoes, the study said. But by 2015, the number of twisters would have increased to a whopping 80.

Yet oddly there has not been any significant increase in the annual number of tornadoes or the number of outbreaks in recent decades.

So what’s going on?

“Something’s up,” study lead author Michael Tippett of Columbia University told the Associated Press. “The tornadoes that do occur are occurring in clusters.”

Man-made climate change could play a role in the uptick.

Because of global warming, you might think there would be more energy around for the severe storms to fire up, but the study said that hasn’t been the case.

One possibility is that increasing wind shear — winds blowing in different directions at different levels of the atmosphere — is a factor. But scientists hadn’t linked increasing wind shear to a warming climate.

“This study raises new questions about what climate change will do to severe thunderstorms and what is responsible for recent trends,” Tippett said.

New year, different weather

Here’s an interesting take from the BBC on why this year’s polar jet stream set up is different from last year.

BBC