Weather buoy tropical Pacific Ocean helped study the El Niño-Southern Oscillation. Moored weather buoys range from in diameter, while drifting buoys are smaller, with diameters of . Drifting buoys are the dominant form of weather buoy in sheer number, with 1250 located worldwide. Wind data from buoys has smaller error than that from ships. There are differences in the values of sea surface temperature measurements between the two platforms as well, relating to the depth of the measurement and whether or not the water is heated by the ship which measures the quantity. The first known proposal for surface weather observations at
Significant weather advisory Significant weather advisory A significant weather advisory (alternately termed as a "significant weather alert" or a "special weather statement", the terminology varies depending on the local National Weather Service Weather Forecast Office) is issued when Doppler radar indicates a strong thunderstorm is producing small hail or high winds whose strength does not reach the criteria to be designated a severe thunderstorm. It does not necessarily account for lightning or flooding. This alert product was created in the early 2000s, and is sometimes a precursor to a severe thunderstorm warning. Many versions of the First Warning weather alert system used by