Weather Service, National, provides forecasts, watches, warnings, statements, observations, and records of the weather and certain water resources in the United States and its territories. It is a part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce. The National Weather Service issues watches and warnings for hurricanes, tornadoes, severe thunderstorms, flash floods, winter storms, and other dangerous conditions. It measures rainfall and river levels to forecast navigation, flood, and water-supply conditions, and issues special weather information for airplane pilots and mariners. The National Weather Service records the climate of the United States and other countries, and studies ways to improve weather forecasting.