Sloppy Pattern: Wettest Day Is Saturday

Is the ongoing pandemic impacting weather forecasts? Surprisingly, the answer may be yes. Data from commercial aircraft (AMDAR) seeds the weather models meteorologists use to predict the state of the atmosphere. ECMWF says fewer flights may degrade upper air wind and temperature forecasts by 15 percent; with a "statistically significant" 3 percent impact on surface pressure forecasts. Satellite data can fill in many of the gaps, but wind forecasts are more dependent on high-flying aircraft, many of which are now grounded.

The best chance of a shower today comes over far southern Minnesota. After a damp but dry Friday, a major storm tracks from Denver to Des Moines to La Crosse by Saturday. Enough warm air gets tangled up into the storm's circulation for rain in the MSP metro, but cold exhaust at the tail-end of the storm Saturday night may leave behind a few slushy inches from Alexandria to Brainerd and Duluth.

Conditions improve Sunday, with a welcome surge of 50s next week. This too shall pass.

Graphic credit above: ECMWF. "Impact of aircraft data on wind forecasts. The plots show the difference in vector wind root-mean-square (RMS) error between forecasts with and without aircraft observations, verified against ECMWF operational analyses (our best estimate of the state of the atmosphere based on all the available information). Yellow/red colours indicate worse forecasts without aircraft reports, and hatching indicates statistically significant differences at the 95% confidence level. The largest impacts are in the range up to 24-hours ahead, but a significant impact is seen in forecasts up to 7 days ahead."

Warm, Humid Weather Could Slow Coronavirus. The Washington Post's Capital Weather Gang has a timely article; here's an excerpt: "...A new study uploaded to the research site SSRN over the weekend finds that 90 percent of the coronavirus transmissions so far have occurred within a specific temperature (37 to 63 degrees) and absolute humidity range. For areas outside this zone, the virus is still spreading, but more slowly, according to the study by two scientists at the Massachusetts Institute of Technology. The paper, which was shared with the public before it was peer reviewed for the benefit of public health officials, notes that even in warm parts of the United States, such as Texas and Florida, cases are not exhibiting the same growth rates as they have in New York and Washington state. The best-case scenario, according to the study’s authors, is that the rate of spread in parts of the Northern Hemisphere will slow as temperatures warm and humidity increases..."

Image credit: "The growth rate of covid-19 cases, normalized by population, through March 22."

Weekend Slush Potential. Most of the precipitation Saturday and Saturday night should fall as rain in the Twin Cities, but plowable amounts of snow are possible north and west of MSP, wit the heaviest amounts (around 10") predicted for the Duluth area. I know - as much as I like snow I hope ECMWF is wrong this time around. Snowfall by midday Sunday: WeatherBell.

Hints of Spring Early Next Week. After a cool, damp week the weather is looking up next week as cold air finally retreats a bit. By Monday it should look and feel like spring again. Maps: Praedictix and AerisWeather.

Cool and Damp Gives Way to a Real Warm Front Next Week. ECMWF shows 60F Monday and upper 60s next Friday? Yes please - let's hope it verifies.

Still Looks Relatively Mild. Most of the USA will be warmer than average as we head into the second week of April, with the exception of the Pacific Northwest. Canada probably won't run out of cold fronts anytime soon.

State and National Parks Open for Visiting. In last Friday's edition of Minnesota WeatherTalk, Dr. Mark Seeley pivots away from weather and climate to remind us about enjoyable forms of social distancing: "...A reminder for citizens who are looking for outdoor destinations that preserve the mandate of “social distancing” during this time of the pandemic emergency: Both State and National Parks are open for visitors. You can take time to appreciate nature and get some fresh air. “Now is a great time to get outdoors,” said DNR CommissionerSarah Strommen, in a statement noting that state parks, campgrounds, recreation areas and public lands remain open statewide. “Parks are a great place to do some social distancing and enjoy the health benefits of nature.” But with the advice of state health officials, the DNR is also canceling or postponing a number of public events in an effort to reduce the number of people congregating and hopefully slow the spread of COVID-19. So while state parks are open for visitors, state park visitor centers, contact stations and other buildings are closed..."

What Is CoCoRaHS? Here are more details from "...CoCoRaHS is the Community Collaborative Rain, Hail and Snow Network, a group of over 20,000 volunteer precipitation observers nationwide. CoCoRaHS observers measure precipitation (rain, hail, and snow) that falls at their location, and share the data online. Reports from CoCoRaHS observers are used by many organizations at the local, state and national level, including the National Weather Service. By volunteering as an observer you become a citizen scientist, and play an important role in documenting how the weather affects your community. All you need to become an observer for CoCoRaHS is a standard 4 inch diameter rain gauge (shown in the photos above, available for purchase on the CoCoRaHS website), and access to the internet to relay reports via the CoCoRaHS app or website. You can report daily, during the rain or snow season, or whenever you are able to take measurements.  It's up to you!  Any reports you can share are greatly appreciated..."

Drop in Aircraft Observations Could Have Impact on Weather Forecasts. ECMWF has the story; here's an excerpt: "...In summary, the number of aircraft observations has gone down significantly over the last couple of weeks both over Europe and globally. In the coming days and weeks, we expect a further decrease in numbers, which will have some impact on forecast quality in the short range, particularly around the polar jet stream level (10–12 km altitude). Sensitivity studies at ECMWF have shown that removing all aircraft data degrades the short-range wind and temperature forecasts at those levels by up to 15%, with significant degradations at all forecast ranges up to seven days. There is a smaller, but still statistically significant, impact on near-surface fields, up to 3% on surface pressure..."

6 Times the Olympics Have Been Postponed or Canceled. Mental Floss has the story; here's a clip: "...The Summer Olympics is the biggest sporting event in the world, typically bringing more than 10,000 athletes from dozens of countries together every four years, The New York Times reports. It's extremely rare for the Summer or Winter Olympics to be postponed or canceled. Since 1896, when the modern Olympic Games began, it has happened only six times—and it usually requires a war. The Olympic Games were canceled during World War I and World War II. The 1940 Summer Games, scheduled to take place in Tokyo, were postponed due to war and moved to Helsinki, Finland, where they were later canceled altogether. The current coronavirus pandemic marks the first time the competition has ever been temporarily postponed for a reason other than war..."

47 F. high in the Twin Cities Wednesday.

46 F. average high on March 25.

47 F. high on March 25, 2019.

March 26, 2012: This is the record early ice-out date on Mille Lacs Lake.

March 26, 2007: Temperature records are shattered across much of central and southern Minnesota and west central Wisconsin. The following records were set: 69 at Alexandria, 75 at Mankato, 77 at Little Falls, 79 at St. Cloud, 81 at Minneapolis-St. Paul and Eau Claire, 82 at Redwood Falls, and 83 at Springfield.

THURSDAY: Cloudy and damp. Stray shower southern MN. Winds: E 5-10. High: 45

FRIDAY: Mostly cloudy, probably dry. Winds: SE 3-8. Wake-up: 35. High: near 50

SATURDAY: Heavy rain likely. Winds: E 10-20. Wake-up: 40. High: 46

SATURDAY NIGHT: Rain changes to wet snow - slushy few inches central Minnesota.

SUNDAY: Mostly cloudy, windy - drying out. Winds: NW 10-20. Wake-up: 33. High: 48

MONDAY: Partly sunny, springy again. Winds: SE 7-12. Wake-up: 39. High: near 60

TUESDAY: More clouds, few rain showers. Winds: E 10-15. Wake-up: 44. High: 55

WEDNESDAY: More sunshine, a nicer day. Winds: N 5-10. Wake-up: 40. High: 58

Climate Stories...

Florida Plant Emits Vast Quantities of a Greenhouse Gas Nearly 300 Times More Potent Than CO2. InsideClimate News has the story; here's an excerpt: "...The plant, owned by Houston-based Ascend Performance Materials, makes adipic acid, one of two main ingredients for nylon 6,6, a strong, durable plastic used in everything from stockings to carpeting, seat belts and air bags. The plant also emits vast quantities of an unwanted byproduct, nitrous oxide, more colloquially known as "laughing gas."  From a climate perspective, the plant's emissions are no joke. Nitrous oxide, or N2O, is nearly 300 times more potent than carbon dioxide as a greenhouse gas. N2O emissions totaling 33,046 metric tons from the plant in 2018, the most recent year for which data is available, equal the annual greenhouse gas emissions of 2.1 million automobiles, according to company data reported to the Environmental Protection Agency and the agency's greenhouse gas equivalencies calculator..."

Image credit: "A chemical plant owned by Houston-based Ascend Performance Materials emitted 33,046 metric tons of nitrous oxide in 2018. That’s equal to the annual greenhouse gas emissions of 2.1 million automobiles." Credit: Center for Land Use Interpretation Database.

Coronavirus: "Nature is Sending Us a Message", Says UN Environment Chief. The Guardian reports: "Nature is sending us a message with the coronavirus pandemic and the ongoing climate crisis, according to the UN’s environment chief, Inger Andersen. Andersen said humanity was placing too many pressures on the natural world with damaging consequences, and warned that failing to take care of the planet meant not taking care of ourselves. Leading scientists also said the Covid-19 outbreak was a “clear warning shot”, given that far more deadly diseases existed in wildlife, and that today’s civilisation was “playing with fire”. They said it was almost always human behaviour that caused diseases to spill over into humans. To prevent further outbreaks, the experts said, both global heating and the destruction of the natural world for farming, mining and housing have to end, as both drive wildlife into contact with people..."

Photo credit: "An orangutan seeks refuge from a bulldozer as loggers smash the base of a tree in the Ketapang district, West Borneo." Photograph: International Animal Rescue.

Greta Got Sick: Climate Nexus has headlines and links: "Swedish activist Greta Thunberg said Tuesday it is “extremely likely” that she had a mild case of coronavirus and is encouraging other young people to stay home during the crisis. In an Instagram post, Thunberg revealed that both she and her father fell ill with Covid-19 symptoms following a trip to Central Europe earlier this month, with her father, Svante, experiencing “much more intense symptoms and a fever.” Thunberg and her father have quarantined themselves away from the rest of their family in Sweden, where tests are limited to only those who go to the hospital. “We who don’t belong to a risk group have an enormous responsibility, our actions can be the difference between life and death for many others,” Thunberg wrote to her 10 million Instagram followers." (New York Times $, Buzzfeed, The Guardian, Reuters).

Scientists Just Discovered a New Vulnerability in the Antarctic Ice Sheet. Chris Mooney reports for The Washington Post (paywall); here's the intro: "Scientists have found a new point of major vulnerability in the Antarctic ice sheet, in a region that already appears to be changing as the climate warms and has the potential to raise sea levels by nearly five feet over the long term. Denman glacier, in East Antarctica, is a 12-mile-wide stream of ice that flows over the deepest undersea canyon in the entire ice sheet before spilling out into the ocean. That subsea trough is more than 2 miles deep, or double the average depth of the Grand Canyon. While there are far deeper trenches in the open ocean, such as the Marianas Trench, in this case the extreme undersea topography lies right on the outer fringe of the Antarctic continent — making it the “deepest continental point on Earth...”

Photo credit: "NASA's IceBridge mission flew over the Denman Glacier region, in East Antarctica, on Oct. 30, 2019. The glacier is creeping down a slope that plunges into extreme depths, new research finds, potentially igniting a feedback process that could unload trillions of tons of ice into the ocean." (Operation IceBridge/NASA).

Locust Swarms, Some 3 Times the Size of New York City, Are Eating Their Way Across Two Continents. Here's a clip from a story at InsideClimate News: "As giant swarms of locusts spread across East Africa, the Arabian Peninsula and the Middle East, devouring crops that feed millions of people, some scientists say global warming is contributing to proliferation of the destructive insects. The largest locust swarms in more than 50 years have left subsistence farmers helpless to protect their fields and will spread misery throughout the region, said Robert Cheke, a biologist with the University of Greenwich Natural Resources Institute, who has helped lead international efforts to control insect pests in Africa.  "I'm concerned about the scale of devastation and the effect on human livelihoods," Cheke said, adding that he also worried about "the impending famines..." 

American Climate Video: On a Normal-Seeming Morning, the Fire Suddenly at Their Doorstep. Here's an excerpt from InsideClimate News: "...Later that morning, Daniel realized his parents' house, just minutes away, where he had grown up would be destroyed by the fire's 50-foot flames. But he stayed put, along with members of his family, to protect his grandparents' house and shelter others. "I was scared," he said. "It was frightening. You know, I've never seen something of a catastrophe at that level. It was horrible." "But," he added, "at that moment it was just kind of do or die." He stayed up late with his family, taking shifts to check for spot fires and to put out embers that came too close to the house. Finally, at around 4 a.m., he went to sleep. When he woke up the next morning, all of the horrors from the day before came flooding back. "It's like, 'Oh yeah, that happened.'" he said. "It became more real at the time." The following weeks were filled with stress. He called and messaged one of his friends from school and got no answer for three weeks. Then, one day, his friend just "showed up..." 

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One Wet Week (Touch of Slush Later Today - Few Inches Saturday Night?)

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Saturday Soaker May End as Plowable Snow North/West of MSP