The word "mesonet" is a combination of two separate words: mesoscale and network. As you probably know, a network is a connected group of items. For example, you have a network of friends. Another example is a network of power lines in a city. The word “mesoscale” is a meteorological term referring to the size of a weather element. Mesoscale elements are between 1 and 150 miles wide or long. Examples include thunderstorms, tornadoes, and hurricane eyewalls. Therefore, a mesonet is a network of weather stations that can be used to measure mesoscale weather elements. The mesoscale covers a large range (1 to 150km) of different weather systems, so how many we can actually measure with a mesonet depends on the spacing between the stations in the mesonet. If the stations are about 20 miles apart it will be hard to observe individual thunderstorms, unless one happens to pass directly over the top of a station. If the stations are 20 miles apart and a hurricane makes landfall directly over the mesonet, then many measurements can be taken in the hurricane eyewall as it moves over the stations in the mesonet. If the stations are 100 miles apart then the eyewall could move between them without any stations ever observing anything of the eyewall.
The University of South Alabama Mesonet has 26 stations, spaced between 4 and 25 miles with an average distance of about 20 miles. The network is located along the north-central Gulf coast. There are stations in 13 counties across Mississippi, Alabama, and Florida.
