More Mild Than Cold Days Into Late December: White Christmas In Doubt

Smaller Snow Events Loom Larger Now

"Paul, back in my day we called an inch or two of snow FLURRIES!" I've seen variations of that theme over the years and I can't disagree. The paradox: as winters shrink, Decembers warm, snowfall becomes more erratic and brown Christmases proliferate, an ordinary, garden variety looms larger. Suddenly "nuisance storms" lead the news; headline-worthy events.

Although a mild signal will linger much of December, odds favor more numerous snowfall events and colder cold fronts in January, historically Minnesota's nippiest month of the year.

A pre-Christmas thaw is imminent, in fact daytime highs rise above 32F from Wednesday into December 23. Fast-moving clippers (starved for southern moisture) drop a brief coating of slush Friday night, Sunday night - again Christmas Eve. But an old fashioned December 25 with knee-deep snow? Not going to happen.

NOAA's GFS model hints at much colder weather as we approach January 1, which sounds right. Consider this: in 10 days daylight starts to increase again.

Southern Detour to the Storm Track. The 12 NOAA GFS model run sweeps the most significant moisture well south of Minnesota, a trend we've witnessed in recent weeks. I see no major deviation from this (dry, relatively mild) pattern until possibly the last few days of December.

A Pre-Christmas Thaw. NOAA's NDFD numbers keep daytime highs above freezing from Wednesday into early next week, so that crystalline coating on your lawn will probably be gone by Thursday afternoon, and lawns may be green-ish on December 25.

Colder Signal Last Few Days of December? ECMWF (above) shows a couple of days above 40F early next week before cooling off. GFS (below) is more aggressive with a late December cool-down. A white New Year's Day anyone?

Then Again... I've seen this numerous times in the last few weeks: GFS suggesting a cold snap, only to have a persistent Pacific signal erase any bitter cold by the next model run. Let's see if there is any consistency to the models before get too excited about a true shift in the pattern. If the GFS solution above verifies a mild signal would continue into early January. Stay tuned.

Praedictix Briefing: Issued Monday, December 14th, 2020:

Mid-Week Winter Storm Watches. While rain and snow are impacting portions of the Mid-Atlantic and Northeast today, a stronger, major winter storm is expected to impact the region as we head into Wednesday and Thursday. This will be due to a nor'easter that develops and moves up the Mid-Atlantic coast. Ahead of the storm, Winter Storm Watches have already been issued from western Virginia to just outside of New York City. However, I would expect Winter Storm Watches to expand across portions of New England later today. Some of the locations already under Winter Storm Watches include:

American Model. Already as we head toward Wednesday morning snow is expected to be falling across portions of the Ohio River Valley, with ice across portions of the Mid-Atlantic. By the midday and afternoon hours, heavy snow will start to fall across the northern Mid-Atlantic and southern Northeastern states. Snow is expected to start around the evening commute Wednesday in the New York City area, lasting through the Thursday morning hours. The heaviest would fall Wednesday Night, when 8-12" could fall. Snow will spread northward to the Boston area Wednesday Night. The American GFS keeps the low a touch farther south, keeping heavier snow out of Boston, but the European brings heavy snow to eastern Massachusetts due to a more northern track.

Modeled Snow Amounts. A big difference in the American GFS and European models is that northern cut-off of heavy snow, with the farther south American model showing considerably less snow for Boston than the European model. The heaviest snow is expected to fall across interior portions of the Mid-Atlantic and southern New England, but heavy snow of at least 6-12" can currently be expected along I-95 from D.C. to Philadelphia, New York City, and (potentially) Boston. This snow would cause major travel disruptions and potentially power outages across the region. We will be ironing out the details of the overall track of this system over the next day or so, and should also get a clearer idea where the snow/wintry mix/rain line sets up. This will help determine how close to the I-95 corridor that 6"+ snow totals will get, as well as overall impacts farther north.

24 Hour 6"+ Snow Probability. As we look at snow probabilities, the greatest potential of seeing at least 6" of snow from Wednesday morning through Thursday morning will be inland toward areas like Cumberland (MD), Harrisburg, Williamsport, and Scranton (PA), and Middletown (NY). However, from Philadelphia to New York to Boston there is at least a 50-70% of that much snow falling during the 24-hour period.

Ice Potential. Farther south, icing will be a problem across eastern North Carolina into Virginia, where odds are above 50% that at least a tenth of an inch of ice could fall on Wednesday. Some models are outputting a quarter to a half an inch of ice across the region, which would cause power outages.

D.J. Kayser, Meteorologist, Praedictix

November 2020 Among Warmest Novembers on Record: NOAA and NASA. Yale Climate Connections reports: "November 2020 was the second warmest November since global record keeping began in 1880, behind the record set in 2015, NOAA's National Centers for Environmental Information, NCEI, reported December 14. NASA rated the month as the warmest November on record, as did the European Copernicus Climate Change Service. The Japan Meteorological Agency rated it as the second-warmest. Minor differences in rankings often occur among various research groups, the result of different ways they handle data-sparse regions such as the Arctic. For the period September-October-November, the Northern Hemisphere had its second warmest autumn, only 0.01°C (0.02°F) behind the record set in 2015, NCEI reported. The Southern Hemisphere had its ninth warmest spring on record..."

Should We Give Snowplows Names? I think Scotland has the right idea (grandpa: what's a snow plow?) If you need a smile check out the Gritter Tracker 2020: "One of Scotland's great winter traditions has returned with the country's hilariously named gritters hitting the roads. Every year the combination of frigid temperatures, festive cheer and unique Scottish humour sees the country's gritter drivers nickname their vehicles, from Yes Sir Ice Can Boogie to License to Chill.Best of all, Scots concerned about the road conditions, or simply keen to track their favourite gritter can do so at the Traffic Scotland website..."

Map credit: Trunk Road Gritter Tracker, Traffic Scotland.

21 F. high temperature in the Twin Cities on Monday.

27 F. average high on December 14.

20 F. high on December 14, 2019.

December 15, 1971: A snowstorm hits Duluth with 10 inches.

TUESDAY: Mostly cloudy, chilly. Winds: SE 7-12. High: 26

WEDNESDAY: Partly sunny, a bit milder. Winds: S 8-13. Wake-up: 18. High: 32

THURSDAY: More clouds than sun. Winds: SE 7-12. Wake-up: 23. High: 33

FRIDAY: PM snow and rain showers. Wake-up: 29. High: 39

SATURDAY: Partly sunny, flurries up north. Winds: S 8-13. Wake-up: 18. High: 36

SUNDAY: Patchy clouds, PM thaw. Winds: S 10-20. Wake-up: 27. High: 37

MONDAY: Partly sunny, relatively mild. Winds: NW 10-20. Wake-up: 32. High: 41

Climate Stories...

Atlas Reveals Climate Change Is Pushing Birds Farther North. A study highlighted at WIRED.com (paywall) caught my eye: "Europe's breeding bird populations have shifted on average 1 kilometer north every year for the past three decades, likely driven by the climate crisis, according to one of the world's largest citizen science projects on biodiversity. The European Breeding Bird Atlas 2 (EBBA2) provides the most detailed picture yet of the distribution of the continent's birds, after 120,000 volunteers and field-workers surveyed 11 million square kilometers, from the Azores in the west to the Russian Urals in the east. The book documents changes in the range of Europe's 539 native bird species in the 30 years since the first EBBA, which was published in 1997 but was based on observations from the 1980s. It shows that since the first study, each population can be found around 28 kilometers further north..."

Electric Airplanes Are Getting Tantalizingly Close to a Commercial Breakthrough. Don't laugh, it's coming (starting with smaller aircraft). Here's an excerpt from Quartz: "For $140,000, you can fly your own electric airplane. The Slovenian company Pipistrel sells the Alpha Electro, the first electric aircraft certified as airworthy by the Federal Aviation Administration (FAA) in 2018. It's a welterweight at just 811 pounds (368 kilograms), powered by a 21 kWh battery pack—about one-fifth the power of what you'd find in a Tesla Model S. For about 90 minutes, the pilot training plane will keep you and a companion aloft without burning a drop of fossil fuel. Those of us without a pilot license will have to wait longer for emissions-free flight—but not much. For all its challenges, 2020 has proven to be a milestone year for electric aviation..."

Emphasizing "Opportunity" to Help Bridge Divide on Climate Action. There will be plenty of opportunity for individuals to take advantage of an emerging clean-energy society, reports Yale Climate Connections: "...So, while it's clear many Republican lawmakers still may feel no sudden desire to tackle climate change, the more their constituents are convinced of the benefits of a clean-energy economy, the more willing their elected GOP senators and representatives will be to support action. This is where strategic and repetitive opportunity-based climate communications become vital. (Let's not forget the reality too that trusted, local messengers are ideal.) Chris Shaw is the research program lead at Climate Outreach. It's a climate communications non-profit based in the UK that conducts climate communication research all over the world, looking to find effective strategies to engage people based on their identity and values. In a recent conversation, Shaw stressed that engaging political moderates and conservatives is vital to foster the sustained climate action necessary to solve complex and long-term climate change challenges.."