A More Active Severe Storm Season in 2021?

March ‘giveth and March ‘taketh away. 60s one day, wet snow and eye-watering winds the next. With a risk of a tornado.

Wednesday brought 2.5 inch diameter hail in Inver Grove Heights and the second earliest tornado watches and warnings on record across Minnesota.

Researchers at the American Geophysical Union examined data from 1952-2011 and found summer warmth had expanded from 78 to 95 days, nationwide. March tornadoes are common in Nashville, but Minneapolis? Severe Weather Awareness Week may need to come sooner.

We are seeing the strongest La Nina cooling phase in the Pacific since 2011. That spring was especially deadly: 1703 tornadoes and 553 fatalities in the US, including the massive Joplin, MO EF-5 tornado. Severe season may be busier than usual this year.

Winds ease today with bright sunshine this weekend. A rain/snow mix Monday (must be a tournament somewhere) gives way to a few cold slaps next week.

Serious Snow. Snow lovers in Denver are giddy. 1 to 3 FEET of snow will pile up this weekend. Wow. Now, about the avalanche threat…

Winter Snowfall Deficit. Although seasonal snowfall values are running closer to average from the Twin Cities and St. Cloud to Duluth, much of Minnesota and Wisconsin is experiencing a snowfall deficit, to date.

Trending Cooler, But Still Above Average Temperatures. NDFD temperature numbers (above) may be a little generous – ECMWF is going colder than this for next week, but temperatures will probably be above average overall into most of next week, in spite of the correction.

A Few Chilly Slaps. ECMWF and GFS model guidance shows a (slight) mild bias through the third week of March, but GFS brings a shot of much colder air into Minnesota by the end of March. Not sure about that (yet). Confidence levels out that far are very low.

A Grudging Warming Trend. With a higher sun angle warmer fronts will be emboldened in the weeks to come, although we all know that spring arrives in starts and stops. Looking out 2 weeks there is evidence of a persistent Pacific flow keeping most of the USA milder than average.

Praedictix Briefing: Issued Thursday, March 11th, 2021:

Significant Winter Storm Expected. Confidence continues to increase that an area of low pressure will develop Friday across the central High Plains Friday, lingering through the weekend before finally getting kicked out to the east. This will produce a major winter storm and potential blizzard in the central Rockies and High Plains. This will be a multi-day storm across the region, and snowfall tallies are expected to be measured in feet. In Denver, this could be one of the largest snowstorms on record – more on that in a moment. The heaviest snow will fall in Denver Saturday into Saturday Night, with the heaviest snow in Cheyenne from Saturday into the morning hours on Sunday. Strong winds are also expected with this system, which would cause whiteout and blizzard conditions.

Winter Storm Watches. Due to this expected major winter storm, portions of Colorado, Wyoming, and Nebraska are under Winter Storm Watches. Some locations include:

• Denver, CO: From late Friday night through late Sunday night for 15-25″ of snow with wind gusts to 35 mph.
• Boulder, CO: From late Friday night through late Sunday night for up to 30″ of snow with wind gusts to 35 mph.
• Cheyenne, WY: From this evening through late Sunday night for the potential of blizzard conditions with total snow accumulation of 18-32″ and wind gusts to 45 mph.
• Colorado Springs, CO: From late Friday night through late Sunday night for the potential of heavy snow. Across El Paso County, snow totals will range from a couple of inches in the southeastern portions to around a foot just north and west of Colorado Springs.
• Scottsbluff, NE: From late tonight through late Sunday night for the potential of blizzard conditions with total snow accumulations of 15-25″ and wind gusts to 45 mph.

Blockbuster Snow Totals Expected. Major snowfall totals are expected across the Front Range, Laramie Range, and the High Plains Friday through Sunday. Snow totals will easily be more than 2 feet in some locations, including areas like Boulder, Estes Park, Fort Collins, Cheyenne, and Laramie. Snow totals in Denver are currently expected to be between 18-24″, with 8-12″ for Colorado Springs. This snow will lead to interrupted travel across the region, with the Colorado DOT already advising people to stay off the roads during the storm with road closures likely (https://www.codot.gov/news/2021/march-2021/statewide-winter-storm-warning). This heavy, wet snow will also lead to the potential of power outages, could bring down tree branches, and will be hard to shovel or even plow as it continues to accumulate on surfaces.

Denver Historical Perspective. Looking at recent years of heavy March snowfall in the Denver area, they had a one-day snowfall total of 13.1″ back on March 23, 2016, which looks like it could be surpassed at the moment (that is NOT the top one day March snowfall on record, though). The National Weather Server in Denver/Boulder says that there is currently a low potential that this system could reach the heights of the March 2003 snowstorm, which between March 17^th and 19^th saw 31.8″ fell.

D.J. Kayser, Meteorologist, Praedictix.

La Nina Could Supercharge This Year’s Tornado Season, Just Like It Did to Deadly Effect in 2011. CNN.com has perspective on what may shape up to be a busier-than-normal tornado season: “…Similar to this year, a moderate La Niña was the main feature in 2011. La Niña, and its counterpart, El Niño, can play a significant role in the position of the jet stream, temperature and precipitation patterns over the US, which all play a role in the formation of severe weather. The El Niño or La Niña conditions in winter months can be used to help pinpoint the tornado frequency during the peak of severe storm season in the spring, recent studies have found. “The flow of warm, humid air from the Gulf of Mexico increases in strength during springs that follow La Niña, which produces the fuel needed to form storms,” Jason Furtado, assistant professor of meteorology at the University of Oklahoma, said. “The stronger flow increases the low-level wind shear that also favors the formation of tornadoes and hailstorms.” The past several months have featured the strongest La Niña since 2011…”

Rating Tornado Warnings Charts a New Path to Improve Forecasts. Yes, there is always room for improvement, according to a post at phys.org: “…A study from the University of Washington and the National Oceanic and Atmospheric Administration describes a new way to rate and possibly improve tornado warnings. It finds that nighttime twisters, summer tornadoes and smaller events remain the biggest challenges for the forecasting community. “This new method lets us measure how forecast skill is improving, decreasing or staying the same in different situations,” said Alex Anderson-Frey, a UW assistant professor of atmospheric sciences. “The tornado forecasting community needs to know what we’re doing best at, and where we can focus training and research in the future...”

15 Ways Life Has Changed Since the Onset of the Covid-19 Pandemic. Fortune has a very good overview here: “…Now, a year on, it seems possible that office life might never be the same again. For millions, working from home has come to signify higher-end employment. Indeed, the gulf is now starkly visible on the streets between those able to perform their jobs remotely, and lower-paid transport, health, or retail workers who have no WFH option. With offices shut, large numbers of canteen and lunch-hour restaurant workers, janitors, and others have lost their jobs altogether. It is a “ticking time bomb for inequality,” says Stanford economist Nicholas Bloom. Despite such wrenching dislocations, most remote employees say that when the pandemic finally ends, they will want the choice of where they work, with many preferring a flexible mix of office and home...”

48 F. Twin Cities high on Thursday.

39 F. average high on March 11.

43 F. maximum MSP temperature on March 11, 2020.

March 12, 2009: The record low temperature for Minnesota for the month of March is set at -35. St. Cloud also sets a new daily record low of -15, breaking the previous record of -12 that was set in 1956. The high temperature in St. Cloud was also only 11 degrees on this date, which also set a new record for the low maximum temperature. This broke the previous record low maximum temperature of 12 degrees that was set in 1896.

March 12, 1990: The temperature at the Minneapolis-St. Paul International Airport hits a record-setting 69 degrees.

FRIDAY: Sunny and cool. Winds: N 5-10. High: 43

SATURDAY: Blue sky, very pleasant. Winds: SW 7-12. Wake-up: 30. High: 58

SUNDAY: Fading sun, stiff breeze. Winds: E 10-20. Wake-up: 33. High: 51

MONDAY: Rain snow mix, risk of a little slush. Winds: E 10-20. Wake-up: 32. High: 35

TUESDAY: Rain and snow showers. Winds: NW 8-13. Wake-up: 30. High: 37

WEDNESDAY: Sunny start, PM flurries. Winds: NW 15-30. Wake-up: 24. High: 38

THURSDAY: Mostly cloudy, feels like winter again. Winds: NW 10-20. Wake-up: 12. High: near 30

Climate Stories….

Climate Change is Making Summers Longer and Winters Shorter. Environment Journal summarizes new research that made me do a double-take: “In the 1950s in the Northern Hemisphere, the four seasons arrived in a predictable and fairly even pattern. However, climate change is now driving dramatic and irregular changes to the length and start dates of the seasons. In order to assess these changes, researchers at the American Geophysical Union looked at historical daily climate data from 1952 to 2011 in order to measure changes in the four seasons’ length and onset in the Northern Hemisphere. They defined the start of summer as the onset of temperatures in the hottest 25% during that time period, while winter began with temperatures in the coldest 25%. They found that, on average, summer grew from 78 to 95 days between 1952 and 2011, while winter days shrank from 76 to 73 days. Spring and autumn also contracted from 124 to 115 days, and 87 to 82 days, respectively….”

America is Woefully Unprepared for Climate Change. It’s all about infrastructure, and being prepared for whatever a Mother Nature (on steroids) throws at us, according to a post at International Policy Digest: “…The nation’s long-neglected infrastructure and outdated building codes were designed for weather scenarios that no longer exist. Texas may seem like the example de-jour, but it is merely the most recent in a long list occurring across the country. From record wildfires destroying 4% of California’s total acreage, and Houston’s three consecutive 500-year floods, to excess rainfalls causing critical dams to fail, climate change’s current impact is pushing infrastructure to the brink of catastrophic collapse. While President Biden has embraced a climate forward agenda, another critical element is needed – mandating national climate-resilient building codes…”

TV Climate Coverage Cut in Half In 2020: Climate Nexus has headlines and links: “Corporate broadcast TV nightly news and Sunday shows devoted just 112 minutes to climate change in 2020, the shortest duration since 2016, according to an analysis from Media Matters. While last year saw the biggest-ever California wildfire, the most named storms in the Atlantic, the costliest thunderstorm in U.S. history, and a presidential race in which climate change played a central role, coverage of climate change dropped in half from 2019 to 2020 across ABC, CBS, NBC and Fox News Sunday. Even when including network morning shows, which gave 267 minutes to climate coverage last year, the climate crisis accounted for just 0.4% of total corporate broadcast coverage. Across TV news, programs consistently failed to note the links between coronavirus and climate change, and broadcasts vastly over-represented white men. In climate segments women accounted for less than a third of guests, while people of color accounted for just 8%, and only six of the 89 guests featured were women of color.” (Media Matters)

Amazon’s Jeff Bezos Plans to Spend $10 Billion by 2030 on Climate Change. OPB reports: “Amazon CEO Jeff Bezos plans to spend the $10 billion he invested in the Bezos Earth Fund by 2030, the fund’s new CEO said Tuesday. Since Bezos announced the fund in February 2020, little has been revealed about how it would be used to combat the climate crisis. Andrew Steer was named as the fund’s CEO on Tuesday, and in a series of tweets, he offered a few details, including that Bezos’ “goal is to spend it down between now and 2030.” That would work out to a pace of more than a $1 billion a year. “The Earth Fund will invest in scientists, NGOs, activists, and the private sector to help drive new technologies, investments, policy change and behavior,” Steer tweeted…”

Sea Level Rise is Increasing Fastest in Populated Coastal Areas, Study Says. New research highlighted at CNN.com caught my eye; here’s an excerpt: “Coastal communities are experiencing sea level rise four times worse than global water rise, according to a new study released Monday. Groundwater pumping, extraction of materials from the ground and sediment production are all happening near the coasts and that is causing the land to actually sink — compounding the effects of a rising sea level. It is no coincidence that these are the same locations where people live, worsening the impacts and increasing the vulnerability. Many of the largest, most populated cities in the world are built along the deltas of major rivers, where there is the added exposure of rivers connecting to the ocean. Much of the coast is uninhabited by people, but where there is civilization, there tends to be a greater rise in water levels...”

The Tide is High – And Getting Higher. A post at WIRED.com (paywall) explains: “…A new study shows that nuisance flooding is exacerbated by dredging and the construction of piers and jetties that were intended to make coastal living easier but are in fact redirecting the flow of incoming ocean water and making high tides higher than ever before. Published Friday in the journal Science Advances, the study compared high and low tide ranges measured during the past 70 years with an older database of historic tidal measurements made in the mid-1800s and recently found in stacks of old boxes stored in an annex of the National Archives in College Park, Maryland. The researchers found that out of 40 coastal tide gauges operated by the National Oceanic and Atmospheric Administration (NOAA), nearly half had measured more nuisance flooding days because of higher local tide ranges. Cities built along coastal estuaries showed the biggest tidal changes…”

Climate Kids Shift Legal Gears: Headlines and links via Climate Nexus: “A group of youth climate activists who sued the U.S. government in 2015 are changing tactics in their fight to force the feds to address climate change. Twenty one young plaintiffs on Juliana vs. United States, who now range in age from 13 to 24, on Tuesday filed a motion in U.S. District Court in Oregon, asking to be allowed to amend the aims of their case. The original case argued the Constitution provides the right to live in a sustainable climate, and demanded courts order the government to create and execute a climate recovery plan. Following a “reluctant” rejection for a full hearing by 9th Circuit Court of Appeals last year, in part on the basis that federal judges lack the power to order the complex policy solutions they sought, the activists are narrowing their goals. Instead, they will ask the court to rule the U.S. energy system violates their constitutional rights to due process and equal protection under the law, and to order the U.S. government to establish a plan to transition off of fossil fuels.” (The Oregonian, Politico Pro $)