The season formerly known as winter may be about to finally arrive in Minnesota in the next 10 days.
First, your backyard thermometer slides gradually down this week. Our fading low-pressure system sneezes out a few more light rain and snow showers as it departs.
— NWS Twin Cities (@NWSTwinCities) November 29, 2016
Siberian chill levels invade Alaska
A bitterly cold sub-zero air mass is pooling over Alaska. Temperatures as cold as -56 F are expected to build over the Alaskan interior this weekend. A modified version of that cold will leak toward the Lower 48 states next week.
The upper air pattern evolving across North America next week suggests much colder air, and the potential for heavy snow is heading for Minnesota.
The National Oceanic and Atmospheric Administration’s Global Forecast System and the European Centre for Medium-Range Weather Forecasts models suggest a deepening storm system tracking toward the Upper Midwest by next Wednesday and Thursday.
It’s still too early to be confident about a precise storm track, but the odds of big snow close to home are growing for next week.
The European Centre model suggests a track closer to the Twin Cities, and cranks out potentially heavy snow Wednesday and Thursday. Again, it’s too far out to put serious credibility in this model product at this point. Still, the notion of around 40 mm or about 1.5 inches of liquid falling as snow in or near the Twin Cities does get your attention.
Call it an outlook this far out, but the potential for heavy snow is growing next week close to home. This outlook can and probably will change, so as we say in the weather biz.
— Scott Dimmich (@ScottDimmich) November 29, 2016
Anatomy of a firestorm
The raging inferno in Gatlinburg, Tenn., in the past 24 hours has destroyed dozens, perhaps over a hundred homes. Tragically three lives have been lost in the blazes so far.
There are both short term and longer term meteorological reasons behind intense fire behavior. Angela Fritz at Capital Weather Gang has a good like at the mechanics behind the Gatlinburg inferno.
— Capital Weather Gang (@capitalweather) November 29, 2016
Arctic still unrealistically warm
I’ve been writing a lot about how the Arctic is broken this month. Bitterly cold air is moving from Siberia into Alaska, but temperatures continue to run well above average from the Arctic to Minnesota this week.
I was asked to provide some additional perspective in this Wired piece by Megan Molteni.
The effects are being felt far below the 66th parallel. States in the Upper Midwest experienced their warmest falls ever, with temperatures running about 15 degrees warmer than average through the second week of November. Minnesota experienced the longest growing season ever recorded: 220 days. And the Twin Cities set a record for the latest frost in history.
On his weather nerd cult blog the Updraft, Minnesota Public Radio chief meteorologist Paul Huttner said that the Arctic “was broken.” Normally, northwest winds blow down from the Arctic over snow-covered ground and iced-over lakes before reaching the US. But this year bare ground all the way up the Arctic circle allowed the sun to warm the upstream air mass more efficiently (no snow means no albedo effect). “The Arctic is North America’s refrigerator,” Huttner says. “If it stops getting as cold as it should, the effects are felt far and wide. I always say that the Arctic is no Las Vegas. Whatever happens in the Arctic, doesn’t stay in the Arctic.”
Which is why climate scientists are gathering data points to try to understand what this anomaly means for the future. It’s too soon to tell if the extreme temperatures are part of a pattern or just an outlier, Serreze says. But if there’s one thing history teaches us, it’s that the Arctic is not as resilient as it once was. Thick layers of old sea ice are the Arctic’s buffer against rare weather events—and that kind of ice has been rapidly disappearing. In the 1980s, multiyear ice made up 20 percent of sea ice cover; today, it’s only 3 percent. As those numbers decline, the Arctic becomes more vulnerable to wide temperature fluctuations.