For many people, the importance of weather and climate forecasts go no further than determining whether to wear shorts or galoshes tomorrow. But when a surprise storm rains out a backyard barbecue, or worse yet, a wedding, the need for accurate and more advance weather prediction hits home.

Now atmospheric scientists say they may soon be able to more accurately predict next week’s weather today, simply by looking at more of the Earth, with much more scrutiny, from space.

A NASA satellite called Aqua, expected to launch next month, should allow more lead time in predicting storms by collecting the most extensive observations of global weather systems ever. The satellite will concentrate on the air above the oceans, the primary source for most of the Earth’s rain, snow and other precipitation, according to researchers with the Jet Propulsion Laboratory.

The short-term weather forecasts that most people watch on the nightly news, as well as predictions of climate changes over weeks and months, all originate from reports and charts provided by the National Weather Service, a branch of the National Oceans and Atmospheric Administration (NOAA), which uses massively parallel computers to process raw atmospheric data. These supercomputers have led to significant forecasting improvements in the last decade, but ultimately rely on the data fed into them.

Ocean waters cover 75 percent of the globe and are breeding grounds for hurricanes, tropical storms and other tempests that hit coastal areas. But NOAA officials told SPACE.com that there is nowhere near enough data on weather systems over ocean waters. Weather stations and balloons, traditional methods of observation, can’t fully cover the vast seas. Buoys and ships can only monitor small parts of the ocean, and land- or air-based radar only detects incoming weather relatively close to coastlines.

So atmospheric scientists have since the 1960s relied on satellites for a better view.

The Aqua spacecraft will orbit the Earth, about 440 miles up (709 km), for six years. Its AIRS instrument will measure infrared radiation as it leaves the planet’s atmosphere, then translate those readings into precise atmospheric temperature, water vapor and cloud information. The satellite will cover an area of 31 miles (50 km) as it orbits the Earth, and it should detect the atmosphere’s moisture content better than any satellite in the sky today, Chahine says.

Equipment aboard AIRS will divide a vertical slice of the atmosphere into almost 2,400 points to measure moisture, compared to the 23 or 24 points used in most satellites today. But how much the increase in data points will increase observation accuracy can only be determined when AIRS measurements can be set alongside current ones.

"I believe, however, that the vertical resolution [which measures air moisture] is going to be much better than we have now, by at least a factor of two or three," said Bill Kuo, a senior scientist with Colorado’s National Center for Atmospheric Research who focuses on short-term weather prediction.

Weather observations describe the atmospheric condition of an area at any given time and usually yield short-term predictions, on the order of a 24 hours to five days, of expected temperatures, humidity and precipitation. Climate studies, on the other hand, take into account a location’s historical weather data and generate more generalized predictions of temperature and precipitation that can span weeks, months or even years.

AIRS researchers say the data from their instrument, combined with the observations of the others aboard Aqua to record humidity and temperature variations, could extend reliable short-term weather forecasts from three days to more than a week.

But most of them would be satisfied if the data allows meteorologists to predict the weather five days from now with the same accuracy they use for tomorrow. In general, Kuo said, weather forecasts beyond 24-hours are accurate about 85 percent of the time, but at five days it’s anyone’s guess, perhaps about 55 percent -- only marginally better than a 50-50 guess.

"At this time, we really have to wait and see, though not because our data won’t be good," said Chahine of Aqua’s impact on weather prediction. "It’s a question of the error in the computer models using our observations."

If a computer model has too much built-in error, inherent to how the model works, then even the most perfect weather data becomes useless after a seven or eight days, he added. And meteorologists believe that one of AIRS’ shining points, the massive amount of data it will gather, could fall flat if it can’t be incorporated into the current prediction models.

"The biggest problem facing satellite weather observation is data assimilation, to extract the most useful information about the current state of the atmosphere," Kuo said.

AIRS researchers said their device will pool its data with that of two other Aqua instruments, the Humidity Sounder for Brazil and the Advanced Microwave Sounder. The Aqua satellite is scheduled to launch no earlier than May 1 from Vandenberg Air Force Base in California and will also carry a separate pair of weather-watching devices to measure cloud properties and radiation from the Earth.