Friday, August 14, 2009

10 things weather forecasters won't say

1. “Long-term forecast? Your guess is as good as ours.”

WEATHER FORECASTERS have gotten pretty good at nailing the outlook two to three days ahead. The problem is, “everyone wants to know what the weather is going to do next weekend,” says Paul Karpowicz, president of the Meredith Broadcasting Group, and forecasting the weather a week or more down the road isn’t so easy.

Eric Floehr, founder of ForecastAdvisor, which tracks the accuracy of predictions, looked at high-temperature forecasts from the National Weather Service, AccuWeather and other organizations for 2008 and compared their
numbers with actual temperatures. When predicting highs for the following day, they were off by about three degrees; when forecasting nine days out, they missed by nearly seven degrees. Doug Young, performance branch chief at the National Weather Service, says his organization’s precipitation forecast for seven days out is only 55 percent accurate. “You’re almost flipping a coin at that point,” he says. Ray Ban, consultant for The Weather Channel, says the best forecasters can do is try to convey the uncertainty of long-range predictions.

2. “We’re pretty accurate—as long as the sun is shining.”

ONE OF THE MOST important things forecasters can do is tell you when bad weather is on the way. Unfortunately, they’re not very good at predicting rain. That’s especially true in summer, when most rainfall comes from thunderstorms, which are small, unpredictable and hard to track. It’s often difficult to tell where they’re headed or whether they’ll produce any rain. Most models for forecasting weather divide the country into a grid of squares that cover about 55 square miles each, though some have smaller squares. Whatever the square’s size, rain, snow, sun and temperature are forecast as a whole for each one. Since most thunderstorms are smaller than the squares, it’s tough to predict exactly where it will rain. “Forecasters are terrible at telling you if rain is going to fall where you live tonight,” says William Gallus, a meteorology professor at Iowa State University.

(The author is a bit harsh in spots, but yes, we need to take our lumps, like any other profession. Then again, you have to be borderline insane to even contemplate wanting to predict the weather. The rest of the article from is here.)

Antarctic glacier "thinning fast"

David Shukman joined a team surveying Pine Island glacier in 2004

One of the largest glaciers in Antarctica is thinning four times faster than it was 10 years ago, according to research seen by the BBC.

A study of satellite measurements of Pine Island glacier in west Antarctica reveals the surface of the ice is now dropping at a rate of up to 16m a year.

Since 1994, the glacier has lowered by as much as 90m, which has serious implications for sea-level rise.

The work by British scientists appears in Geophysical Research Letters.

The team was led by Professor Duncan Wingham of University College London (UCL).

Calculations based on the rate of melting 15 years ago had suggested the glacier would last for 600 years. But the new data points to a lifespan for the vast ice stream of only another 100 years.

The BBC article is here.

The cold facts about melting glaciers

Host: Jessica Robertson

Most glaciers in Washington and Alaska are dramatically shrinking in response to a warming climate.

USGS scientist Edward Josberger discusses research from the past 50 years to measure changes in the mass (length and thickness) of three glaciers in Alaska and Washington. These are the longest such records in North America and among the longest in the world.

To hear the entire podcast - direct from the scientists who have been studying these key glaciers in Washington and Alaska (which respond to "climate", not day to day fluctuations in "weather") click here.

Sunday, August 9, 2009

America's National Parks: canaries in the climate change coal mine

"The house of America is founded upon our land and if we keep that whole, then the storm can rage, but the house will stand forever." – President Lyndon B. Johnson

Despite the easy association of American culture with prosperity and modernity, historically, it was America’s National parks that were seen as a reflection of national character, as well as national priorities.

Travel to America’s National Parks, and you are quickly reminded that it is not our wealth, not our cars, not our designer boutiques, our high rise buildings or our suburban homes that define America. Rather, as so many have said, it is these parks that are the crown jewels of our country.

I was reminded of this over the last two weeks as I hiked through the lunar landscape of Utah’s Capitol Reef National Park and the pine forests, streams and crystal blue lakes of California’s Yosemite National Park.

The rest of the article is here.