Squalls

A squall is a sudden, brief increase in surface wind speed, typically lasting from a few minutes up to about half an hour. It is usually associated with convective weather, most commonly thunderstorms, but can also occur along gust fronts from other storm systems or during the passage of a cold front. Squalls are often accompanied by heavy precipitation, reduced visibility, and sometimes thunder, hail, or snow.

Formation and characteristics can vary. In many cases a squall results from downdrafts and a gust front that distributes momentum from an organized storm to the surface, producing a sharp wind increase and sometimes a brief shift in wind direction. Non-convective environments can also generate squalls, but convective activity is the most typical cause. On ships and at coastal locations, squalls are a common hazard during stormy conditions at sea.

Impact and reporting. Squalls pose risks to aviation, maritime operations, and outdoor activities due to sudden changes in wind, rain or snow, and reduced visibility. In weather reporting, squalls are noted as rapid wind gusts associated with convective activity; forecasts may highlight the likelihood of squalls when thunderstorms are anticipated. The term is related to broader convective phenomena such as squall lines, which are long bands of thunderstorms that can produce multiple squalls along their path. Related concepts include gust fronts, microbursts, and derechos.