Historic December Severe T-Storm Outbreak

Two weeks ago, if you had told me that 5-20” snow falling on a Friday would be followed by a tornado threat 5 days later…in Minnesota, I would have said you’re watching Syfy, the science fiction TV channel, not The Weather Channel.

Yesterday was historic, with record warmth, moisture and a severe weather outbreak more typical of mid-May than mid-December. We can eventually analyze how much of this was natural variability vs. another climate signal, but it was an incredible display of weather-whiplash, and extremes trending more extreme.

Minnesota winters, increasingly, are bringing more ice, and the big concern this morning is black ice, after a temperature tumble overnight with winds over 55 mph. A very icy start gives way to some 20-degree sunshine by afternoon.

I still don’t see any big storms through Christmas, just a decorative coating of flakes Saturday, maybe a little light snow Christmas Eve.

Expect highs in the 20s and 30s next week – and I envision a cold, quiet, tornado-free Christmas this year.

Perspective on Wednesday Evening’s Severe T-storm Outbreak. Dr. Mark Seeley weighs in at Minnesota WeatherTalk: “…Historical perspective: This storm system may indeed be a singularity (one off) in Minnesota history for the month of December considering all of its unusual attributes together. One historical analogy is the storm of March 31, 2014 over southwestern Minnesota where citizens in Yellow Medicine, Lincoln, Lyon, and Yellow Medicine Counties had to endure both a blizzard warning and a tornado warning simultaneously during the afternoon, another singular weather episode in Minnesota history. Reality check is that both of these unusual storm systems may be tied to our changing climate.”

Severe T-storm Warnings by Month/Year
Iowa Environmental Mesonet (IEM)

First December Severe Storm Warnings in the Modern Record. Since 1986 the Twin Cities office of the National Weather Service has never issued a severe storm warning, much less a tornado warning, for the MPX coverage area. Until yesterday.

Thursday Future Clouds/Precipitation

Snow Tapers – Ice Lingers. A few inches of snow fell over central and northern Minnesota overnight, but in the metro area the big story is glaze ice; flash-frozen after last night’s abrupt temperature tumble. Anything that was wet and puddly yesterday is glazed over this morning.

No More Spring Fever In Sight. Temperatures run fairly close to average into early next week with a thaw possible again by Monday, but no more 50s or 60s brewing anytime soon. A light nuisance snowfall is possible Saturday – models suggest a little snow on Christmas Eve. Still predicting a white(ish) Christmas this year for most of the state.

ECMWF Temperatures for MSP
NOAA GFS Temperatures for MSP

Late December Warming Trend? In spite of spasms of chilly air, nothing polar is in sight through the end of December – probably nothing subzero (for the metro area). Looking 2 weeks out NOAA’s GFS model shows a resumption of moderate Pacific air for much of the USA (except for New England) with temperatures running above normal for much of the nation.

January-March Climate Model Temperature Anomalies

Warm Bias to Linger? NOAA’s suite of climate models show a mostly-warmer bias from January into March, although a few of the simulations pull colder air into Minnesota and northern tier states. Will the pattern flip or will temperatures trend above average much of the winter? The answer to that question is anything but obvious, but my (small) bet is on a continuation of warmer than normal, with a few polar punches in January and February.

Why Tornado Warnings Weren’t Enough to Prevent Tragedy. A number of factors magnified the death toll from last Friday’s tornado swarm in the Mid South, as reported by The New York Times: “…Weather prediction technology has become so precise in recent years that tornadoes are almost always foreseen, a vast, if somewhat unheralded, improvement in forecasting. In the late 1980s, before the use of Doppler radar and other technologies, meteorologists were able to issue warnings for 46 of 88 violent tornadoes in the United States, or just more than half, federal data shows. In recent years, powerful tornadoes have been preceded by warnings 97 percent of the time. Yet despite the advances in forecasting, tornadoes that strike continue to have deadly consequences — whether because of poor decisions, weak construction or just bad luck. The storms that hit on Friday and Saturday left at least 88 people dead in five states...”

Obligatory bathtub image
Paul Douglas

Family Survives Tornado in Blown-Away Bathtub. It wouldn’t be my first choice, but if no basement or sturdy shelter is available it’s better than nothing. Kait8.com reports: “A Trumann family piled into the bathtub Friday night and came out in the street. Jada Madden is a mother of two and a full-time student. Her fiancé and youngest child, an 8-month-old daughter, were home when a tornado hit their neighborhood. They’re only alive to tell the story because of a last-second decision. “As soon as we hit the tub, everything was gone. It felt like I was going to be buried into the ground. I didn’t think I was going to be able to get out,” Madden said. “We were at the back of the house, that’s where the bathtub was at, and we ended up in the street.” Madden grabbed her daughter and wrapped a pillow around her. They all three hunkered down to brace for impact. Seconds later, their house was gone. Their cars were across the street in their neighbor’s yard. Their bathtub was in the middle of the road, with the shower wall on top of them. Somehow, they were able to lift the debris and escape the tub…”

Amazon Worker Deaths in Tornadoes Raise Questions About Tornado Training and Cellphone Policy. NBC News reports: “After tornadoes killed six workers at an Amazon distribution center in Edwardsville, Illinois, some Amazon workers have raised concerns about how the company handles emergency responses and about cellphone policies it plans to reintroduce next year, which workers have described as draconian. Workers at two neighboring Amazon facilities in Edwardsville, just outside St. Louis, who were also in the path of the tornadoes overnight Friday said they have had little training in preparing for tornadoes and bristled at a company policy that multiple sources have said the company is trying to bring back Jan. 1, which would ban workers from having cellphones at work...”

Dylan Moriarty/The Washington Post

Researchers Ponder Why Friday’s Tornadoes Led To So Many Deaths, Despite Ample Warning. Capital Weather Gang provides reasons why this was no ordinary tornado outbreak: “Despite accurate forecasts and timely warnings, Friday night’s tornado outbreak was December’s deadliest on record. Researchers of many stripes, from engineers and forecasters to social scientists, now face the burning question: Why? Experience from past tornado disasters assures that the answers will be complex and multidimensional, taking months if not years to pin down. But the evidence suggests the timing of the tornadoes, coming in the dark of night, their exceptional intensity and the population density of the region hit were all key factors in the catastrophe — which advanced warning could not overcome...”

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Severe Weather “New Normal”, US Emergency Chief Warns After Tornadoes. Phys.org has the post; here’s an excerpt: …“This is going to be our new normal,” Deanne Criswell, head of the Federal Emergency Management Agency, told CNN’s “State of the Union” as she did a round of national Sunday morning talk shows before she headed to Kentucky to assess the damage and help coordinate the federal response. “The effects that we’re seeing from climate change are the crisis of our generation,” the FEMA chief added. Criswell warned of the challenge that the United States faces in addressing such severe weather events. “We’re seeing more intense storms, severe weather, whether it’s hurricanes, tornadoes, wildfires,” she said on ABC’s “This Week.” “The focus I’m going to have is, how do we start to reduce the impacts of these events?…”

Graphic: NBC News NOW

How “Goldilocks Conditions” Spawned Rare December Tornado Outbreak. NBC News has a look at the meteorological conditions leading up to last Friday’s historic outbreak: “…The rare December tornadoes that tore through Kentucky, Missouri, Illinois, Tennessee and Arkansas were shocking in their intensity and their timing, experts said. And they were the kinds of violent storms that raise worrisome questions about what extreme weather events may look like in a warming world. “The heat and humidity across the South was pretty uncharacteristic for this time of year,” said Victor Gensini, an associate professor of atmospheric sciences at Northern Illinois University. “I remember waking up, looking at the weather maps and saying, ‘Geez, this looks a lot more like late April than mid-December.’” The unseasonable warmth helped fuel volatility in the atmosphere that can generate strong thunderstorms…”

The map shows land surface temperature anomalies from March 19 to June 20, 2020. Red colors show areas that were hotter than average for the same period from 2003-2018; blues were colder than average. Data from the Moderate Resolution Imaging Spectroradiometer on NASA’s Aqua satellite.
Joshua Stevens/NASA Earth Observatory

Arctic Temperatures Soared to an Unprecedented 100 Degrees in 2020, Scientists Confirm. Washington Post’s Capital Weather Gang has an update – here’s an excerpt: “…Shortly after the temperature spike, researchers determined Siberia’s anomalously warm months, as well as Verkhoyansk’s record-breaking temperature in June, were virtually impossible without human-induced climate change. Climate change made the prolonged heat from January to June at least 600 times more likely; such extended heat in the region would occur less than once in 80,000 years without the observed increase in temperatures. To verify the June record, an international committee of experts conducted a thorough analysis of data, including from European weather forecast models. The group also evaluated information from the Russian meteorological agency on the type of equipment used, quality-checks, calibration of the instrument, monitoring techniques and data from surrounding stations...”

Paul Douglas

“Atmospheric River”, “Bomb Cyclone” and “Snowmageddon”. How Do Scientists Come Up With Weather Terms? Great question. A post at The Durango Herald provides some clarity: “Sierra cement, yellow snow, pineapple express. Haboob, Texas norther, bomb cyclone. They seem like ridiculous terms used to describe a messy bedroom or types of ice cream. But they’re actually weather terms, and meteorologists use them. Sierra cement refers to the heavy, wet snow that often falls on the West Coast. Yellow snow is not urine, but snow turned golden by pine or cypress pollen. And pineapple express is a band in the atmosphere that transports moisture from Hawaii and the tropics to the coasts of the U.S. and Canada. Who develops these terms and how they enter the public lexicon are often murky…”

Looking to Reduce Your Carbon Footprint? Surprise – Your Christmas Tree is Edible. Uh, no. Mental Floss has some important caveats: “…The operative word there is might—not all Christmas trees are edible. As NPR reports, all cypress, yew, and cedar trees are poisonous. And even if your tree is of an edible variety, it may have been treated with pesticides or some other chemical that makes it toxic to ingest. In short, you shouldn’t try to whip up a Christmas tree dish unless you’re positive that yours is a chemical-free spruce, pine, or fir. Once you’ve confirmed that, you can safely begin looking for recipes. A good place to start is How to Eat Your Christmas Tree, a cookbook created by UK-based baker Julia Georgallis and published in October 2020…”

54 F. Record Twin Cities high temperature on Wednesday. Old record: 51 F. in 2014.

29 F. average MSP high on December 15.

25 F. maximum temperature at MSP on December 15, 2020.

December 16, 2000: A surface low pressure system tracks east-northeast through Iowa on the 18th and then into western Illinois during the early evening hours. Extreme south central and southeast Minnesota received 6 to 10 inches of snow, including Albert Lea with 10.5 inches, Kiester and Bixby with 6.0 inches.

December 16, 1972: Fairmont has its fifteenth consecutive day with lows at or below zero degrees Fahrenheit.

December 16, 1940: A snowstorm hits much of Minnesota. Water equivalent of the snow was 1.27 inches at Winona.

Paul Douglas

THURSDAY: Icy, some PM sunshine. Winds: W 15-30. High: 24

FRIDAY: Cloudy with a few flakes. Winds: NE 7-12. Wake-up: 15. High: 22

SATURDAY: Coating of light snow. Slick roads. Winds: NW 10-20. Wake-up: 19. High: 23

SUNDAY: Partly sunny, a little nicer. Winds: S 10-20. Wake-up: 11. High: near 30

MONDAY: Blue sky, risk of a thaw. Winds: N 8-13. Wake-up: 24. High: 34

TUESDAY: Sunny peeks, chilly. Winds: N 5-10. Wake-up: 9. High: 21

WEDNESDAY: Chilled sunshine. Winds: W 5-10. Wake-up: 10. High: 19

Climate Stories…

New York Times Infographic

Rising From the Antarctic, a Climate Alarm. The New York Times (paywall) visualizes rising concerns about what’s happening in the waters surrounding Antarctica; here’s an excerpt: “…For centuries this ocean was largely unknown, its conditions so extreme that only a relative handful of sailors plied its iceberg-infested waters. What fragmentary scientific knowledge was available came from measurements taken by explorers, naval ships, the occasional research expeditions or whaling vessels. But more recently, a new generation of floating, autonomous probes that can collect temperature, density and other data for years — diving deep underwater, and even exploring beneath the Antarctic sea ice, before rising to the surface to phone home — has enabled scientists to learn much more. They have discovered that global warming is affecting the Antarctic current in complex ways, and these shifts could complicate the ability to fight climate change in the future...”

January-March Climate Model Temperature Anomalies

Arctic Report Card Says We Are Failing The Arctic: Climate Nexus has headlines and links: “The Siberian town of Verkhoyansk hit temperatures above 100°F on June 20, 2020, breaking the record for the highest Arctic temperature on record the World Meteorological Organization has confirmed. The announcement comes as NOAA’s 16th-annual Arctic Report Card warned, as the NOAA administrator told reporters, heating “trends are consistent, alarming and undeniable.” Some of the bad news is relatively expected, if still terrifying: the region’s oldest ice is melting and Greenland is losing an average of about 280 billion metric tons of ice every year. Some of the news is more surprising: beavers are moving into melting tundra, and their ponds are accelerating permafrost thaw. Climate change, primarily caused by the extraction and combustion of fossil fuels, is heating the planet, but the effects are even more extreme in polar regions. The high temperatures are also fueling wildfires, which in turn pump massive amounts of planet-heating CO2 into the atmosphere while thawing soils release even more potent planet-heating methane. Melting Arctic ice also means increased maritime travel, leading to more trash in previously frozen-over waters.” (Heat record: AP, Washington Post $, Bloomberg $, USA Today, E&E News, The Hill; Report card: Washington Post $, AP, The Conversation, Politico Pro $, CNN, The Globe and Mail; Trash: Reuters, Gizmodo; Commentary: The Hill, Gabrielle Dreyfus, Rafe Pomerance, and Daniel Bodansky op-ed; Climate Signals background: Sea ice decline, Glacier and Ice sheet melt, Polar amplification, Extreme heat and heatwaves, Wildfires)

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CC0 Public Domain

Study: Winter Tornadoes to Get More Powerful as World Warms. A post at Phys.org caught my eye – here’s a clip: “…The combination of a longer and wider track with slightly stronger winds means some rare winter tornadoes that are killers now will have nine times more the power by the end of the century if carbon dioxide levels continued to rise, according to a study presented at the American Geophysical Union conference Monday. The study, which pre-dates the devastating Mayfield, Kentucky, tornado outbreak, looks at strength and not frequency of big tornadoes as climate change progresses. Not peer reviewed yet, it was presented in poster form as a peak at new research to be published later. “There is a potential for events in the future that are more intense that would not have been as intense in the current climate,” said study author Jeff Trapp, head of atmospheric sciences at the University of Illinois, Urbana-Champaign…”

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From Killer Heatwaves to Floods, Climate Change Worsened Weather Extremes in 2021. Emergencyemail.org has a list of some of the most extreme events of this year: “Extreme weather events in 2021 shattered records around the globe. Hundreds died in storms and heatwaves. Farmers struggled with drought, and in some cases with locust plagues. Wildfires set new records for carbon emissions, while swallowing forests, towns and homes. Many of these events were exacerbated by climate change. Scientists say there are more to come – and worse – as the Earth’s atmosphere continues to warm through the next decade and beyond. Here are some of the events Reuters witnessed over the past year:

February — A blistering cold spell hit normally warm Texas, killing 125 people in the state and leaving millions without power in freezing temperatures.

Scientists have not reached a conclusion on whether climate change caused the extreme weather, but the warming of the Arctic is causing more unpredictable weather around the globe…”

Hold the carbon please…

Zara Party Dresses Are Made From Carbon Emissions. Fast Company reports: “Before it was made into holiday dresses, the silky black fabric used in a new capsule collection from Zara started life as carbon emissions. At a steel mill in China, a startup called LanzaTech uses microbes to turn the factory’s captured emissions into ethanol, something that would usually be made from fossil fuels. The ethanol is then processed into monoethylene glycol, one of the components used to make polyester. Earlier this year, Lululemon announced that it was experimenting with a version of the fabric to make its high-end yoga pants. Inditex, the fashion group that owns Zara, has also been working with the fabric. Zara’s new capsule collection is the first clothing to come to market using the technology. (Because polyester is made from only 20% monoethylene glycol, the new fabric’s climate impact is not eliminated, but it is reduced…”)

Change in favorable tornado days between 1979 and 2020, in days per decade.
Image: Victor Gensini

Tornado Outbreak Offers Climate Warning. Andrew Freedom does a good job of explaining what we know and don’t know – highlighting emerging science regarding attribution. It looks like an apparent south/east shift of traditional Tornado Alley may be a climate signal. Here’s a blurb from Axios: “…Tornado trends, such as a shift in their geographic distribution, and increased variability from year to year, are what scientists expect to see in a warming world, according to Gensini.

  • Projections show an increase in major outbreaks in the mid-South and Southeast in particular, he said.
  • Harold Brooks, senior scientist at the National Severe Storms Laboratory in Oklahoma, who also studies tornadoes and climate change, told Axios that the increase in days with favorable conditions for tornadoes in the South and Southeast already stands out as a climate-related signal.
  • Gensini compared tornado attribution today to the steroids era of baseball. Pinning an individual home run on steroid use is difficult, he said, but in the aggregate the trends are evident...”

Tornado Watches, 2007 – 2017

How the Climate Crisis is Affecting Tornadoes. CNN.com has a good explainer about “attribution” – how a warming climate may be impacting tornado frequency and intensity: “…When you start putting a lot of these events together, and you start looking at them in the aggregate sense, the statistics are pretty clear that not only has there sort of been a change — a shift, if you will — of where the greatest tornado frequency is happening,” Gensini told CNN. “But these events are becoming perhaps stronger, more frequent and also more variable.” Research by Gensini found that over the past four decades, tornado frequency has increased in vast swaths of the Midwest and Southeast, while decreasing in parts of the central and southern Great Plains, a region traditionally known as “tornado alley.” Some studies also indicate climate change could be contributing to an eastward shift in tornado alley, for instance, resulting in more tornadoes occurring in the more heavily populated states east of the Mississippi River, such as this tornado outbreak…”