Why Meteorologists Over-predict Snowfall Amounts – Major Storm Potential Next Week

+10.3 F. November temperatures are running more than 10F warmer than average at MSP, to date.

38 F. high in the Twin Cities Tuesday.
33 F. average high on November 29.
34 F. high on November 29, 2015.

November 30, 2006: Lake effect snow occurs downwind of the larger lakes in Minnesota. Northwest winds from 8 to 12 mph accompanied an air mass in the single digits. This moved over lakes with water temperatures near 40 degrees. A cloud plume from Mille Lacs stretched all the way to Siren Wisconsin. Snow from Ottertail Lake and Lake Lida reduced visibilities at Alexandria to a few miles. Even some low clouds formed from Lake Minnetonka and were observed at Flying Cloud Airport.
November 30, 2000: A surface low pressure system moves into extreme southwestern Minnesota from South Dakota. The heaviest snow reported was in the 6 to 8 inch range, and fell in a narrow band just southwest of the Minnesota River in and around the Canby (Yellow Medicine County) and Madison (Lac Qui Parle County) areas. Northeast winds rising out of the Minnesota river valley up the slopes of the Buffalo Ridge in southwest Minnesota helped enhance snowfall amounts. The northeasterly winds between 10 and 20 mph were responsible for producing visibilities in the one to two mile range.
November 30, 1991: A storm dumps 14 inches of snow in the Twin Cities in about 12 hours.
November 30, 1896: Bitterly cold temperatures are reported across Minnesota. A low of 45 below zero occurs at the Pokegama Dam.

Snowfall Inflation – Major Storm Next Week?

A single snowstorm can drop up to 39 million tons of snow. Which is why, as a profession, meteorologists tend to over-predict snow. The biggest sin a forecaster can commit is missing a tornado – or predicting flurries, only to wake up to a FOOT of flurries.

That’s why it pays to take all the snowfall predictions on TV, radio, internet and your favorite app, and divide by 2. That will be closer to the mark.

One other timeless truth: if I predict 3-6 inches, chances are you’ll only hear 6 inches.

Some of our biggest snowstorms have spun up on the leading edge of fresh outbreaks of bitter, Canadian air. One such heavy snow potential is brewing for the middle of next week. It’s too early to get too excited, but ECMWF guidance hints at a plowable to crippling snowfall for Minnesota next Wednesday and Thursday with near-blizzard conditions. Confidence levels are still very low – keep checking in for the latest.

A slushy coating is possible tonight but skies dry out for the weekend.

The coldest air since mid-February arrives late next week, possibly preceded by a big pile of white.


* ECMWF forecast map above valid next Thursday morning, December 8, courtesy of WSI.



Who Gets The Most Blizzards in the USA? Western Minnesota and the Dakotas: take a bow. Here are a couple of excerpts from an interesting story at The Buffalo News: “…This maximum distribution is approximately the same now, except the number of verified blizzards has increased in the United States. Some of that may be due to climate factors or improved reporting or, in my opinion, the removal of the temperature requirement; we just don’t know…The high frequency over the northern and high plains is more closely tied to the average path taken by deep winter cyclones/low-pressure systems, placing that swath of the country most often in the colder quadrant of those storms, with howling winds and heaviest snow…”

Map credit: “Climatology of Blizzards in the Conterminous United States, 1959–2000.”



ECMWF Forecast Next Tuesday – Friday. This potential event is still a week away, so this is more of a curiosity than a forecast. Odds are future model runs will shift, but for now the European tries to spin up a deep (979mb) storm with near-blizzard conditions for the Midwest next Wednesday and Thursday. Will it verify? The Euro is good, but hardly infallible. My gut: 1 in 3 chance of a full-blown blizzard.




84-Hour Snowfall. Here is NOAA’s 12km snowfall product showing total accumulation through Saturday morning at 12z. Heaviest amounts (15-20″) are projected to fall on Maine, with plowable snows for the Dakotas, the Rockies and highest terrain of the Pacific Northwest. Map credit: Tropicaltidbits.com.



Forget Inches, There Are 3 Categories of Snowstorms. My favorite college professor told us to “forget about inches”, since we can’t predict snow down to the inch, and instead classify storms into 3 categories: nuisance (enough to coat roads and sidewalks but travel isn’t impacted too badly), “plowable” (just as the and word implies, enough snow to shovel, scrape and plow) and crippling (where everything stops – traffic is paralyzed and business pretty much shuts down). I’ve been borrowing the scale since 1983 at KARE-11. It has stood the test of time. Thank you Dr. Cahir at Penn State.


Minnesota Annual Precipitation Record Broken. It’s official; Waseca wins the Golden Rain Gauge Award, with a record 53.78″ of precipitation (and counting). Details from the Minnesota DNR: “Waseca, in south central Minnesota, has set the official state precipitation record, coming in with the highest annual precipitation total for a National Weather Service Cooperative Observation site. As of November 28, 2016 Waseca had a total of 53.78 inches with more precipitation on the way. The old statewide annual record was 53.52 inches of precipitation at St. Francis in Anoka County in 1991…”



Above Average Temperatures Into Early Next Week. ECMWF guidance (WeatherBell) shows a gradual cool-down into Friday, followed by another upward blip in temperature early next week before much colder air arrives the latter half of next week.


Temperatures Recover Mid-December. At least east of the Mississippi, while colder than average readings prevail from the Northern Plains into the Pacific Northwest. Bitter air poised over Alaska and western Canada may push southward in time for another parade of storms by Christmas.


NAO Turns Neutral/Positive. There’s a fairly strong correlation between the NAO (North Atlantic Oscillation) and the strength of the polar vortex, the winds spinning around the far northern hemisphere. A negative phase of the NAO usually means weaker winds, a wavier pattern that favors bitter air penetrating farther south. A positive phase of the NAO: stronger winds keeping the coldest air bottled up north of the USA. After a negative (colder) turn next week NOAA’s NAO forecast shows an uptick by mid-December.


Spastic Climate Models: Milder December for Eastern USA? My confidence level is very low, but just for laughs and giggles here is the latest Climate Forecast System (CFSv2) from NOAA for the month of December. A few days ago it looked bitterly cold for most of the USA, newer runs trending milder from the Great Lakes and New England to the Southeast. Place your bets. Map: WeatherBell.


“Thunderstorm Asthma” Kills 8 in Australia. The death toll is up to 8 from the freakish combination of pollen and thunderstorm moisture and wind; here’s an excerpt of an update at The New York Times: “…Mr. McGann was one of thousands of people in Melbourne having an attack of thunderstorm asthma. They flooded the city’s emergency rooms, swamped ambulance call lines and joined lines around pharmacies during six hours on Nov. 21. All were struggling for breath. About 8,500 people went to hospitals. Eight have died, and one remains in intensive care more than a week after a thunderstorm surged across Melbourne, carrying pollen that strong winds and rain broke into tiny fragments. Perennial ryegrass seeds were swept up in whorls of wind and carried from four million hectares of pasturelands (about 9.9 million acres) that lie to Melbourne’s north and west. If broken into fragments, they are so fine that they can be inhaled…” (Image credit: UK Daily Record).

11 Ways The Atmosphere Went Bonkers This October That You Probably Didn’t Notice. Here’s an excerpt and a partial list from a story at Yahoo! Finance: “…Each month, the National Oceanic and Atmospheric Association (NOAA) releases a list of some of the most significant trends in the climate from the past month. Here are some of the most drastic things that took place this October:
  • The global average temperature was 1.31 degrees Farenheit above the 20th-Century average of 57.1 — tied with 2003 for the third hottest October ever recorded.
  • In the Arctic, 980,000 square miles of sea ice (an area larger than Texas and Alaska combined) went missing. That left Earth with a whopping 28.5% less Arctic ice than the 1981-2010 average, or the lowest levels ever recorded.
  • The Antarctic saw sea ice levels that were 290,000 square miles below average — 4% below the 1981-2010 average, or the second-lowest October ever.
  • The continental US experienced its third-warmest October in the 122-year record.
  • Alaska experienced its driest October since records began in 1925.
  • Finland experienced its driest October since national records began in 1961 and Norway experienced its fourth-driest since records began in 1900…”


Many 500-Year or 1,000-Year Floods Reported This Year. Here’s a nugget from a story at Weather or Not and CDAPress.com: “It’s almost hard to believe, but areas that are currently reporting major drought conditions experienced massive flooding earlier this year. Normally, we see these huge 500-year or 1,000-year flood events less than once per year. For 2016, there have been nearly a dozen events, which indicates that our cycle of Wide Weather “Extremes” is still going strong with no signs of letting up anytime soon. Most of the big flood events were east of the Rockies. In early June, Houston reported 22 inches of rain, which was a 500-year event. Dallas picked up 16 inches of rain, also a 500-year flood...”

File photo: David Gatley, FEMA.


On Virginia’s Vulnerable Coast, Fear of Flooding On The Rise. The Norfolk/Tidewater region of Virginia is nearly as vulnerable to rising seas as south Florida. ABC News reports: “...Experts warn that flooding will likely increase in Virginia’s Hampton Roads region, where Virginia Beach and six other cities are clustered on or near the state’s low-lying coast. The land is sinking and the sea is rising at the highest rate on the East Coast, they say. Global warming threatens to draw more intense rain storms up the Eastern Seaboard. Fears are growing that this historically prime location for military installations threatens livelihoods as much as it sustains them. The Atlantic meets the mouth of the Chesapeake Bay here along with the confluence of three rivers. The world’s largest naval base sits in Norfolk, nearby. A commercial port, ship builders and a railroad help fuel the economy…” (File image credit here).

The Next Fashion Trend: Weather Forecasting. Good luck with that. The fashion industry is getting a taste of climate volatility and weather disruption, as reported at The Wall Street Journal: “…Weather fluctuations have increasingly been putting fashion designers and clothing retailers on the defensive. Merchandise is often ordered months in advance based on what the weather typically is at that time of year. But when temperatures are different from what was predicted—milder-than-usual winters, cold springs or otherwise inconsistent weather—clothes that are all wrong for the climate stay on racks and get discounted, hurting sales. Last winter was the warmest on record for the contiguous U.S., says Jake Crouch, a climate scientist at the National Oceanic and Atmospheric Administration’s National Centers for Environmental Information. The average temperature was 36.8 degrees Fahrenheit, 4.6 degrees above average, with some parts of the country even higher above average. That led to less demand for heavy winter coats...”

Photo credit: “Calvin Williamson, a professor of math in the Fashion Institute of Technology’s School of Liberal Arts, teaches ‘Predictive Analytics for Planning and Forecasting,’ a new class.” Photo: Caitlin Ochs for The Wall Street Journal.


Oil and Water: 11,700 Gulf Oil Spills Since BP Raise New Fears. WWL-TV in New Orleans is running the series; here’s an excerpt of what they found: “…Recent discoveries of illegal, unreported oil discharges and systematic dumping of chemicals from rigs and platforms have raised new fears about environmental damage in the Gulf of Mexico, more than six years after the worst oil spill in U.S. history. Tracking of federal data by the environmental watchdog group SkyTruth shows more than 11,700 oil spills have been reported in the Gulf of Mexico since the BP oil spill ended in July 2010. But the rate of spills also has slowed significantly, from 245 a month in 2012 to 80 in October 2016…”


From Peak Oil to Peak Oil Demand In Just 9 Years. Here’s an excerpt from Bloomberg View: “Peak demand for oil is the big new thing. True, the International Energy Agency, in the annual World Energy Outlook it released earlier this month, didn’t envision a peak coming before 2040 barring a big acceleration in anti-climate-change efforts. But at least it’s talking about the possibility, and forecasting a slowdown in demand growth in the meantime. Others think the big day is coming much sooner. Simon Henry, the chief financial officer of Royal Dutch Shell, recently predicted a demand peak “between five and 15 years hence.” And as Bloomberg’s Javier Blas and Laura Blewitt pointed out last week, even the IEA thinks that demand from passenger cars, long the biggest users of oil, has already peaked…”

Graphic credit: International Energy Agency


Zika Surfaces in Texas, Likely To Be First Local Transmission. The Washington Post has more details: “Texas health authorities said Monday that a Brownsville woman is infected with Zika, a case that could make the south Texas city the second place in the continental United States where the mosquito-borne virus is spreading locally. Laboratory testing confirmed that the 43-year-old patient, who is not pregnant, had been infected. State and local health authorities said she reported no recent travel to any location with ongoing Zika transmission and no other risk factors…”

Photo credit: “A female Aedes aegypti mosquito feeds from a researcher at Rockefeller University.” (Alex Wild).



Another U.S. City Commits To 100% Renewable Energy. Details via Solar Industry: “The St. Petersburg, Fla., City Council has formally approved the city’s commitment to transition to 100% clean, renewable energy. According to the Sierra Club, St. Petersburg represents the first city in Florida and the 20th city in the U.S. to make such a commitment. In a unanimous vote, the City Council Committee of the Whole has allocated $250,000 of BP settlement funds from the 2010 Deepwater Horizon oil spill to an Integrated Sustainability Action Plan (ISAP), which will chart a roadmap to 100% renewable energy in St. Petersburg…”


The Only Way to Commute in 2025? Check out the concept vehicle from Terrafugia, a car that transitions into a 4-seat, hybrid VTOL (vertical take-off and landing) airplane. These won’t come cheap, and they’re still 8-12 years away, but wow. I hope it’s real. When I imagined the 21st century it came with flying cars – we seem to be inching closer to that vision. Here are more details and a mind-blowing YouTube video: “Terrafugia is excited to premier the new Outer Mold Line for the TF-X™, Terrafugia’s vision for the future of personal transportation. The TF-X™ will be a four-seat, vertical takeoff and landing (VTOL) hybrid electric aircraft that makes flying easier and safer than ever before. Visit terrafugia.com for more information.”


How A Father and Son Helped Create Weather Forecasting As We Know It. Atlas Obscura has a terrific article; here’s an excerpt that explains why we refer to weather zones as “fronts”: “…The plethora of weather data the Bjerknes were receiving also allowed Jack to continue monitoring convergence lines and refining his theory. By the fall of 1918, he had made a discovery: these lines of weather were connected with cyclones—large air masses that rotate around low atmospheric pressure. He published his observations in 1919. Though he didn’t yet know it, Jack had identified one of the most characteristic features of weather maps and weather forecasting. These features, too, would be linked with war, named for their resemblance to the lines of advancing armies. Jack Bjerknes had discovered the “front...”

Map credit: “An image from the 1951 Compendium of Meteorology showing front activity, based on Bjerknes’ model.” Internet Archive/Public Domain


TODAY: Rain/snow mix, wet roads during the day. Winds: NW 8-13. High: near 40

WEDNESDAY NIGHT: Wet snow, coating to an inch on some lawns. Low: 33

THURSDAY: Clouds linger, few flurries around. Winds: NW 8-13. High: 38

FRIDAY: Sunny peeks, seasonably chilly. Winds: W 7-12. Wake-up: 28. High: 36

SATURDAY: Mix of clouds and sun, dry sky. Winds: S 5-10. Wake-up: 24. High: 38

SUNDAY: Mostly cloudy, flurries or sprinkles. Winds: W 10-15. Wake-up: 30. High: near 40

MONDAY: Mostly cloudy, milder than average again. Winds: S 10-20. Wake-up: 31. High: 45

TUESDAY: Sloppy mix may develop. Winds: N 10-15. Wake-up: 34. High: 37


Climate Stories…

Why Extreme Weather Is The New Normal. Here’s an excerpt from CNN.com: “…Just as we have seen an increase in droughts, we have also seen a rise in floods. Four studies have concluded that water vapor in the atmosphere is increasing globally. This happens because warmer air results in more evaporation, and evaporation leads to more available water vapor to create precipitation. That could be why we are seeing more floods. Flooding in Louisiana in August was the worst disaster to hit the United States since Superstorm Sandy. In one week, 6.9 trillion gallons of rain fell, and it wasn’t even a named storm or a hurricane. It was simply a slow-moving system that stalled over Louisiana, dumping way more rain than the soil could soak up. Watson, Louisiana, had 31.39 inches of rain during the storm…”


Pope Urges World Leaders Not To Hobble Climate Change Pact. Reuters reports: “Pope Francis urged national leaders on Monday to implement global environmental agreements without delay, a message that looked to be squarely aimed at U.S. President-elect Donald Trump. Addressing a group of scientists that included theoretical physicist Stephen Hawking, the pope gave his strongest speech on the environment since the election of Trump, who has threatened to pull out of the 2015 Paris Agreement on climate change. “The ‘distraction’ or delay in implementing global agreements on the environment shows that politics has become submissive to a technology and economy which seek profit above all else,” Francis said…”

Photo credit: “Pope Francis greets Stephen Hawking (R), theoretical physicist and cosmologist, during a meeting with the Pontifical Academy of Sciences in Vatican, November 28, 2016.” Osservatore Romano/Handout via Reuters.


A Wrenching Choice For Alaskan Towns In The Path of Climate Change. America has already seen its first climate refugees, in Louisiana and Alaska. Here’s an excerpt from The New York Times: “…With its proximity to the Arctic, Alaska is warming about twice as fast as the rest of the United States and the state is heading for the warmest year on record. The government has identified at least 31 Alaskan towns and cities at imminent risk of destruction, with Shaktoolik ranking among the top four. Some villages, climate change experts predict, will be uninhabitable by 2050, their residents joining a flow of climate refugees around the globe, in Bolivia, China, Niger and other countries. These endangered Alaskan communities face a choice. They could move to higher ground, a wrenching prospect that for a small village could cost as much as $200 million. Or they could stand their ground and hope to find money to fortify their buildings and shore up their coastline…”
Photo credit:

The project announced this month by the naval base and The Nature Conservancy could serve as a model for U.S. military installations worldwide endeavoring to protect their coastlines from the impacts of global warming, said Lily Verdone, coastal project director for the Ventura office of the national nonprofit. The U.S. Department of Defense has defined climate change as a major threat to America’s national security. That danger is especially acute at coastal military installations, according to a 2014 report on climate change. The Defense Department is one of the largest coastal landowners in the United States and controls more than 200,000 acres of oceanfront property in California, including Naval Base Ventura County and its six miles of coastline and 2,500 acres of wetlands…”

File image: Oxnard Chamber of Commerce.



Design Bridges For a Wetter Climate. If we’re going to rebuild infrastructure, why not make everything we do more weather-proof and climate-resistant, technologies we can export to the rest of the world? Here’s an excerpt of an Op-Ed at The Des Moines Register: “We’ve seen this picture too often recently: bridges and roadways overtopped by floodwaters. Such infrastructure, designed to last 100 years based on historical data, is experiencing damage at more frequent intervals. Precipitation, as part of Iowa’s climate, clearly has changed. To build roadways and bridges to last 100 years into the future, should we inform design by augmenting historical data with future scenarios from climate models? Climate scientists consider the early 1970s to be approximately when global climate records began showing a clear influence of increases in greenhouse gases. Although varying widely from year to year, Iowa’s statewide annual precipitation was remarkably constant from 1893 through 1970, decreasing 0.04 inches over 98 years. However, between 1971 and 2016, the annual total increased by 3.7 inches. For those years, the increase from April through June has been 4.2 inches…”


America’s Coastal Cities Don’t Have to Drown, Dutch Experience Shows. Here’s an excerpt of a sobering article at Honolulu’s Star-Advertiser: “…Olsen says there is no simple and one-size-fits-all solution to the problems that sea level rise will bring. There is no way the United States will be able to surround all of its cities with sea walls. “The United States is just too big. There’s too much coastline,” he says. The U.S. has about 12,000 miles of ocean and sea coastline. By comparison, the Netherlands protects 270 miles of seacoast. The American reality is that some cities will probably be sacrificed. Parts of cities certainly will be sacrificed. “The U.S. coasts will look very different in 50 years,” Olsen says. “We’re going to have to learn to be like Venice, to learn to live with water…” (File photo credit: Andrew Demp, Yale).


Unchecked Arctic Melting: How Some Communities Are Starting to Adapt. Here’s an excerpt from Christian Science Monitor: “The Arctic ecosystem may be heading toward permanent change as high temperatures and longer summers continue to alter the region, according to a report published by the Arctic Council on Friday. In the first comprehensive assessment of ecosystems and societies in the region, the Arctic Resilience Report highlights how human activities and global warming may have caused some ecosystems to reach key tipping points, thus threatening the way of life and economies of local communities…”

Photo credit: “An Inuit village in Greenland is pictured in this September 2013 handout photo provided by Ida Moltke. New research by the Arctic Council shows how unprecedented high temperatures and rapid ice melt in the Arctic are driving communities to tipping points of survival.” Ida Moltke/Handout/Reuters/File.


Sand’s End. The seas are rising. That’s not a climate model, but based on observations. And that has implications for hundreds of millions of people around the planet. Here’s an excerpt of an article from MSN.com: “…For years the sea has been eating away at the shore, and the city has spent millions of dollars pumping up sand from the seafloor to replace it, only to have it wash away again. Every handful of sand on Miami Beach was placed there by someone. That sand is washing away ever faster. The sea around Miami is rising a third of an inch a year, and it’s accelerating. The region is far from alone in its predicament, or in its response to an eroding coast: it’s becoming hard to find a populated beach in the United States that doesn’t require regular infusions of sand, says Rob Young, director of the Program for the Study of Developed Shorelines at Western Carolina University. Virginia Beach, North Carolina’s Outer Banks, New York’s Long Island, New Jersey’s Cape May, and countless other coastal cities are trapped in the same cycle, a cycle whose pace will become harder to maintain as the ocean rises…”

Photo credit: Wikipedia.