Mesoscale meteorology
Mesoscale meteorology studies atmospheric processes and weather systems spanning roughly 2 to 2,000 kilometers and lasting minutes to about a day.
Convection: Vertical atmospheric motion driven by buoyancy, often when warm air rises through cooler air. Buoyant updrafts and downdrafts organize many mesoscale clouds and storms.
Thunderstorm: A storm that produces lightning and thunder, usually with convective clouds and precipitation. Individual thunderstorms are compact examples of mesoscale atmospheric organization.
Numerical weather prediction: The use of computer models that solve equations of atmospheric motion to forecast weather. Forecast models must represent mesoscale dynamics and resolve their evolving structures.
Microscale meteorology: The study of atmospheric processes on scales smaller than a few kilometers, including turbulence and local flows. Microscale processes are finer than the weather systems emphasized here.
Flash flood: A rapid flood caused by intense rainfall, sudden runoff, or dam failure, developing over minutes to hours. Slow-moving or training mesoscale storms can produce extreme rainfall in small areas.
Coriolis force: The apparent deflection of moving objects caused by Earth's rotation. It shapes larger mesoscale circulations, though it matters less at the smallest scales.
Squall line: A line of thunderstorms that often produces strong, gusty winds along its leading edge. Squall lines demonstrate how storms can organize into long-lived mesoscale bands.
Weather radar: A remote-sensing instrument that detects precipitation and estimates its location and motion using radio waves. Radar tracks storm structure and motion at the spatial and temporal scales central to this field.
Synoptic meteorology: The study of large-scale weather systems, such as fronts and cyclones, spanning thousands of kilometers and several days. Synoptic systems are broader and longer-lived than mesoscale phenomena.
Downburst: A strong downdraft that spreads outward after reaching the ground, producing damaging winds. Downbursts are compact storm hazards generated by mesoscale convective processes.