Sea-surface temperatures from NASA's Jason-1 satellite. Credit: NASA

While the start of summer mostly brings warm weather and sunny skies, it also marks the start of the Atlantic hurricane season, which officially begins June 1 and lasts until November 30. (For the Pacific Ocean, hurricane season starts on May 15.) This year, NASA is using, as it has in the past, its orbiting satellites to study and research tropical cyclones, and it will provide the data that the National Oceanic and Atmospheric Administration (NOAA) National Hurricane Center uses in advanced models and hurricane predictions.

So far, the news is good. The satellites, which measure such things as storm and surface winds, sea-surface heights and temperatures, rainfall intensity, lightning, water vapor, humidity, cloud development, and atmospheric pressure, indicate that sea-surface temperatures in the tropical Atlantic are below normal. Such lower-than-normal temperatures could "starve" developing hurricanes of their driving force--waters warmer than 80 °F--meaning fewer hurricanes.

Despite the good news, peak hurricane season is not until late summer and early fall, and NASA's William Patzert says that oceanic and atmospheric conditions can change dramatically. "You can be clobbered no matter what the expert outlook is today," he says. People need to remain prepared.

Hurricane Gustav moves along the southern side of Jamaica on August 29, 2008. The image was taken by the MODIS instrument on NASA's Aqua satellite. Credit: NASA

Hurricane Fay's wind speeds on August 19, 2008, taken using NASA's QuickSCAT satellite. Highest wind speeds, in purple, are over 46 miles per hour. Credit: NASA

A map of Hurricane Dolly's rainfall over the Gulf of Mexico and Texas from July 25 to 28, 2009, created using NASA's TRMM satellite. Red and orange are highest rainfall totals: over six inches. Credit: NASA