The Palestine Herald, Palestine, Texas

Community News Network

April 17, 2013

Everybody talks about the weather, but it's not easy to predict

(Continued)

When the almanacs risk testable predictions, they often fail. The Old Farmer's Almanac predicted that the Atlantic corridor would average 47.5 degrees for March 2013, off by nearly four degrees. That might seem like a reasonably good guess, except that anyone with access to historical averages — that is, anyone with an Internet connection — can usually get within a few degrees by sticking near the mean. The almanac's prediction for February was 29 degrees, nine degrees below the actual temperature, and the forecast for January was off by five degrees.

Critics of the almanacs are nearly as old as the almanacs themselves. A forecaster at the U.S. Weather Bureau complained about the almanacs' inaccuracy in 1905, and a Harvard professor did the same in a public address in 1926. But we simply can't let go of the dream of weather omniscience.

Generally speaking, forecasters who make predictions months in advance rely on analog techniques, which means they look for patterns in the current weather, then find similar patterns in prior years. Their predictions are based on what happened in the past. The problem is that this technique has never been shown to work particularly well. The atmosphere is a complicated place, and it's very difficult to say that a single past year, or even a combination of past years, is enough like this year to make accurate predictions.

The National Weather Service relies more on dynamic forecasting. The agency's experts observe the weather systems at work in the atmosphere, then use mathematical and physical models to calculate what will happen next. The technique is far more reliable, but it has its limits.

"We sustain higher accuracy out to two to three days in advance; then it starts dropping off faster at days six through eight," says Louis Uccellini, director of the National Weather Service.

Text Only
Community News Network
  • Sunburn isn't the only sign of summer that can leave you itchy and blistered

    You've got a rash. You quickly rule out the usual suspects: You haven't been gardening or hiking or even picnicking, so it's probably not a plant irritant such as poison ivy or wild parsnip; likewise, it's probably not chiggers or ticks carrying Lyme disease; and you haven't been swimming in a pond, which can harbor the parasite that causes swimmer's itch.

    July 30, 2014

  • Survey results in legislation to battle sexual assault on campus

    Missouri U.S. Sen. Claire McCaskill joined a bipartisan group of senators Wednesday to announce legislation that aims to reduce the number of sexual assaults on college campuses.

    July 30, 2014

  • An alarming threat to airlines that no one's talking about

    It's been an abysmal year for the flying public. Planes have crashed in bad weather, disappeared over the Indian Ocean and tragically crossed paths with anti-aircraft missiles over Ukraine.

    July 30, 2014

  • Sharknado.jpg Sharknado 2 set to attack viewers tonight

    In the face of another "Sharknado" TV movie (the even-more-inane "Sharknado 2: The Second One," premiering Wednesday night on Syfy), there isn't much for a critic to say except to echo what the characters themselves so frequently scream when confronted by a great white shark spinning toward them in a funnel cloud:
    "LOOK OUT!!"

    July 30, 2014 1 Photo

  • 20140729-AMX-GIVHAN292.jpg Spanx stretches into new territory with jeans, but promised magic is elusive

    The Spanx empire of stomach-flattening, thigh-slimming, jiggle-reducing foundation garments has expanded to include what the brand promises is the mother of all body-shaping miracles: Spanx jeans.

    July 29, 2014 1 Photo

  • Medical marijuana opponents' most powerful argument is at odds with a mountain of research

    Opponents of marijuana legalization are rapidly losing the battle for hearts and minds. Simply put, the public understands that however you measure the consequences of marijuana use, the drug is significantly less harmful to users and society than tobacco or alcohol.

    July 29, 2014

  • linda-ronstadt.jpg Obama had crush on First Lady of Rock

    Linda Ronstadt remained composed as she walked up to claim her National Medal of Arts at a White House ceremony Monday afternoon.

    July 29, 2014 1 Photo

  • Can black women have it all?

    In a powerful new essay for the National Journal, my friend Michel Martin makes a compelling case for why we need to continue the having-it-all conversation.

    July 29, 2014

  • Dangerous Darkies Logo.png Redskins not the only nickname to cause a stir

    Daniel Snyder has come under fire for refusing to change the mascot of his NFL team, the Washington Redskins. The Redskins, however, are far from being the only controversial mascot in sports history.  Here is a sampling of athletic teams from all areas of the sports world that were outside the norm.

    July 28, 2014 3 Photos

  • 'Rebel' mascot rising from the dead

    Students and alumni from a Richmond, Va.-area high school are seeking to revive the school's historic mascot, a Confederate soldier known as the "Rebel Man," spurring debate about the appropriateness of public school connections to the Civil War and its icons.

    July 28, 2014