Think predicting the weather isn't important? At least one forecast changed the course of World War II. In the weeks before D day, Allied commander Dwight Eisenhower dragooned every meteorologist in Britain and ordered them to do two-day and three-day forecasts using the Allies' one great advantage---the network of weather stations in the Atlantic. The Nazis had already abandoned their Greenland weather station, their last observation post west of Europe. When a blustery, rain-heavy storm arrived on June 4, the German generals assumed they were safe from an amphibious assault. But Ike's meteorologists spotted a break---a low-pressure calm heading east from Scotland. "OK, we'll go," Ike announced with soldierly hope. Luckily for the British weathermen, the skies cleared on schedule on June 6.
Though many of us now get our forecasts from TV anchors who chatter like parakeets, prediction itself has improved. Weather balloons, satellites and computers have helped clear the crystal ball.
"It turns out the easier part of the job has been predicting tomorrow and the next day, for temperature and wind," says A.E. "Sandy" MacDonald, director of the Forecast Systems Laboratory of the National Oceanic and Atmospheric Administration, the Commerce Department agency that feeds its research to the National Weather Service. "The harder part of the job has been to get really good forecasts of precipitation."
The NWS' wind and temperature forecasts are correct 80 percent to 90 percent of the time, says MacDonald. But predictions of heavy rain, snow and hail are accurate only 25 percent of the time, he admits, thought he prefers the more attractive comparison to a batting average of .250.
"It's hard to hit a baseball," he points out. "It's also hard to predict an inch of rain tomorrow."
The reason: Temperature and wind patterns stretch over vast areas---across hundreds and even thousands of miles. But most weather systems that drop precipitation are so small that they often slip through the gridwork of balloons sent up twice daily every 400 to 500 miles across the country.
So what does that "50 percent chance of rain tomorrow" really mean? It means your local weatherperson has his or her hands on predictions from National Weather Service forecasters who have compared the next few days' weather pattern in your area to their database of similar past weather patterns at that time of year. And the feds' records have shown that five times out of ten, it rained.
1998's Weirdest Weather Moments
Portland, Oregon records its hottest April day ever---90 degrees.
Santa Barbara, California gets more rain In one month---21,74 inches---than in any month before.
Billings, Montana welcomes the New Year with a 60-degree temperature---the warmest January I in its history.
Tucson, Arizona sees its February rainfall total increase four times over normal.
Black Hills, South Dakota gets 102.4 inches of snow from one February snowstorm, twice the previous record.
Dallas, Texas endures 29 straight days of temperatures over 100 degrees in July.
Williston, North Dakota hits 26 degrees on June 4, its coldest temperature on record for June.
New York's Central Park gets 22.5 inches of snow on March 22. Nine days later, the mercury hits 86 degrees.
Lake Erie doesn't freeze during February, for the third time this century.
Florida suffers a terrible drought. In May and June, 80 percent of the state is at the same drought level as a desert. Devastating fires follow.
New England gets an early summer. Boston reaches 89 degrees in March. Portland, Maine hits 88.
Washington, D.C. doesn't dip below 60 degrees for eight straight days, despite the fact that it's January.
Hawaii, which had weathered five times the normal rainfall in 1996 and 1997, experiences a drought so severe it has to import drinking water.
