(SST)

– A thunderstorm with winds of 58 mph or more or hail 3/4-inch diameter or larger. Structural wind damage may imply the occurrence of a severe thunderstorm.

Long, wedge-shaped clouds associated with the gust front. Shelf clouds indicate the downdraft or outflow of a thunderstorm.

– a progressive wave in a horizontal air flow that leads to lower air pressure and possibly unsettled weather.

Precipitation that is intermittent, in space, time, or intensity and is falling from a cumuliform cloud.

– Solid grains of ice which form from the freezing of raindrops or the refreezing of melted snowflakes. These small, transparent ice pellets usually bounce when they hit a hard surface.

– In probability of precipitation statements, usually equivalent to a 20 percent chance.

– Pollution formed by the interaction of pollutants and sunlight (photochemical smog), usually restricting visibility, and occasionally hazardous to health.