Nobody caught outside today needed the three-day forecasts on TV to feel the lid of that atmospheric box starting to close shut.

For instance, the Weather Channel provides a local three-day forecast that automatically updates each time the frame dials in.

Timing for the Son Tay Raid was advanced by 24 hours based on the three-day forecast.

When the authors started, their algorithm took a full day to perform a three-day forecast when using a grid with a 10km square resolution.

Forecasters say a five-day tracking forecast now has the same reliability as a three-day forecast 15 years ago.

"Our five-day forecast is now as accurate as the three-day forecast was seven years ago."

A new and more powerful computer producing a detailed 10-level numerical model of the Earth's atmosphere doubled the accuracy of the three-day forecast.

Federal officials said their five-day hurricane forecasts were now just as reliable as a three-day forecast was 15 years ago.

Within seconds, a three-day forecast appears.

The change came after two years of testing showed that the five-day forecasts were as accurate as three-day forecasts had been 15 years earlier.