Weather Glossary – S


SCATTERED CLOUDS – Sky condition when between 1/10 and 5/10 are covered.

SCATTERED SHOWERS – Showers covering 25 to 54 percent of an area.

SEA BREEZE – A wind that blows from a sea or ocean towards a land mass. Also known as an onshore breeze.

SEA SURFACE TEMPERATURE (SST) – Surface temperature data collected using IR satellite imagery, buoy and ship data.

SEVERE THUNDERSTORM – 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.

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

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

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

SLEET – 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.

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

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

SNOW – Unless qualified by such words as ” occasional” or ” intermittent” , a prediction of snow indicates a steady fall of a few hours or more.

SNOW ADVISORY – An advisory issued when snow is expected to create hazardous or restricted travel conditions, but not as severe as expected with a winter storm.

SNOW FLURRIES – Short duration of intermittent light snowfall with little if any accumulations.

SOO – Science and Operations Officer.

SOUTHERN OSCILLATION – A periodic reversal of the pressure pattern across the tropical Pacific Ocean during El Nino events.

SPC – Storm Prediction Center. Located in Norman, OK. This office is responsible for monitoring and forecasting severe convective weather in the continental U.S. This includes the issuance of Tornado and Severe Thunderstorm Watches.

SPS– Special Statement

SPRING TIDE – Semi-monthly tide of increased height due to the new or full moon.

SQUALL LINE – A line of thunderstorms or squalls extending over several hundred miles.

STABLE AIR – air with little or no tendency to rise, that is usually accompanied by clear dry weather.

STACKED– A pressure system which shows up in the same general location on every height analysis or forecast chart. This is an indication low pressure is weakening (filling) or a pressure system is stalling.

STATIONARY FRONT – A transition zone between airmasses, with neither advancing upon the other.

STRAIGHT LINE WINDS– Damaging thunderstorm winds produced as air rushes downward from a thunderstorm. Often called gust fronts, downburst, or microburst winds these winds originate from thunderstorm downdrafts and may produce damage similar to that of a tornado.

STRATOSPHERE– The layer of the atmosphere above the troposphere, where temperature increases with height.

STRATUS– Flat low level clouds.

SUBSIDENCE– Sinking air that is associated with warming air and little cloud formation.

SUBTROPICAL JET – The branch of the jet stream that is found in the lower latitudes.

SUPERCELL- A highly organized thunderstorm with a rotating updraft, known as a mesocyclone. It poses an inordinately high threat to life and property. Often produces large hail, strong winds, and tornadoes.

SUPERCOOLED WATER – water that stays in liquid form if undisturbed even though it has been cooled to a temperature below its normal freezing point.

SUSTAINED WINDS– The wind speed obtained by averaging the observed values over a one minute period.

SWELLS – Ocean waves of regular and longer duration than wind waves.