Weather terms starting with S

436 terms

Solar Cycle An approximately 11-year pattern in the number of sunspots, coronal mass ejections (CMEs), solar flares, and other solar activity.
Solar energy Electromagnetic energy transmitted from the sun (solar radiation). The amount that reaches the earth is equal to one billionth of total solar energy…
Solar Maximum The month(s) during the 11-year solar cycle when the number of Sunspots reaches a maximum.
Solar Minimum The month(s) during the 11-year solar cycle when the number of Sunspots is lowest.
Solar Noon The time of the day, at a specific location, when the sun reaches its highest, apparent point in the sky; equal to true or due, geographic south.
Solar Radiation A general term for the visible and near visible (ultraviolet and near-infrared) electromagnetic radiation that is emitted by the sun.
Solar Sector Boundary (SSB) In solar-terrestrial terms, the apparent solar origin, or base, of the interplanetary sector boundary marked by the larger-scale polarity inversion lines.
solar variability changes in the amount of radiation emitted by the sun due to the sun's internal dynamics.
Solar Wind A stream of plasma coming out of the Sun in all directions at very high speeds—an average of about 400 km/sec, or a million mph.
SOLN Solution
SOLNS solutions
Solstice The two times of the year when the sun is apparently farthest north and south of the earth's equator; usually occurring on or around June 21 (summer…
SOO Science and Operations Officer
sounding A set of data measuring the vertical structure of an atmospheric parameter (temperature, humidity, pressure, winds, etc.) at a given time.
Source Any place or object from which air pollutants are released. Sources that are fixed in space are stationary sources and sources that move are mobile…
Southern Great Plains (SGP) site The first of the ARM research sites, the SGP site is located in south Kansas and north Oklahoma.
Southern Oscillation (SO) - a "see-saw" in surface pressure in the tropical Pacific characterized by simultaneously opposite sea level pressure anomalies at Tahiti, in the…
Southern Oscillation Index A numerical index measuring the state of the Southern Oscillation. The SOI is based on the (atmospheric) pressure difference between Tahiti and Darwin…
Space Environment Center (SEC) - This center provides real-time monitoring and forecasting of solar and geophysical events, conducts research in solar-terrestrial physics, and…
SPC Storm Prediction Center
SPCLY Especially
SPD 1) Speed 2) On a buoy report, ten-minute average wind speed values in m/s.
Spearhead Echo A radar echo associated with a downburst with a pointed appendage extending toward the direction of the echo motion.
Special Avalanche Warning Issued by the National Weather Service when avalanches are imminent or occurring in the mountains. It is usually issued for a 24 hour period.
Special Fire Weather Meteorological services uniquely required by user agencies which cannot be provided at an NWS office during normal working hours.
Special Marine Warning (SMW) A warning product issued for potentially hazardous weather conditions usually of short duration (up to 2 hours) producing sustained marine…
Special naphtha All finished products within the naphtha boiling range that are used as paint thinners, cleaners, or solvents.
Special Tropical Disturbance Statement This statement issued by the National Hurricane Center furnishes information on strong and formative non-depression systems.
Specific Gravity The ratio of the mass of a body to an equal volume of water.
Specific Heat The amount of heat required to raise a unit mass of a substance through one degree, expressed as a ratio of the amount of heat required to raise an equal…
Specific Humidity The weight of water vapor, per unit weight of dry air.
Specific Yield The ratio of the water which will drain freely from the material to the total volume of the aquifer formation.
Spectral Density A radar term for the distribution of power by frequency.
Spectral Wave Density On a buoy report, energy in (meter*meter)/Hz, for each frequency bin (typically from 0.03 Hz to 0.40 Hz).
Spectral Wave Direction On a buoy report, mean wave direction, in degrees from true North, for each frequency bin.
spectral width A measure of the spread of the Doppler spectrum and consequently is sensitive to the spread in the particle size spectra.
Spectrum Width This WSR-88D radar product depicts a full 360 degree sweep of spectrum width data indicating a measure of velocity dispersion within the radar sample…
Spectrum Width Cross Section This WSR-88D radar product displays a vertical cross section of spectrum width on a grid with heights up to 70,000 feet on the vertical axis and distance…
Speed Shear The component of wind shear which is due to a change in wind speed with height, e.g.
speleothem a mineral deposit formed in caves. Two types of speleothems are stalagmites and stalactites.
SPENES NESDIS Satellite Precipitation Estimates
Sphere Calibration Reflectivity calibration of a radar by pointing the dish at a metal sphere of (theoretically) known reflectivity.
Spillway A passage for surplus water to flow over or around a dam.
Spillway Crest The lowest level at which water can flow over or through a spillway.
Spin-Up Slang for a small-scale vortex initiation, such as what may be seen when a gustnado, landspout, or suction vortex forms.
SPKL Sprinkle
Split Flow A flow pattern high in the atmosphere characterized by diverging winds. Storms moving along in this type of flow pattern usually weaken.
Splitting Storm A thunderstorm which splits into two storms which follow diverging paths (a left mover and a right mover).
SPLNS Southern Plains
Sporadic E In solar-terrestrial terms, a phenomenon occurring in the E region of the ionosphere, which significantly affects HF radiowave propagation.
SPOTNIL In solar-terrestrial terms, a spotless disk.
Spotting Outbreak of secondary fires as firebrands or other burning materials are carried ahead of the main fire line by winds.
Spray An ensemble of water droplets torn by the wind from an extensive body of water, generally from the crests of waves, and carried up into the air in such…
SPRD Spread
Spring The point at which the water table meets Earth's surface, causing water to flow from the ground.
Spring equinox Spring equinox See equinox.
Spring Tide A tide higher than normal which occurs around the time of the new and full moon.
SPS Severe Weather Potential Statement
SQLN Squall Line
Squall A strong wind characterized by a sudden onset in which the wind speed increases at least 16 knots and is sustained at 22 knots or more for at least one…
Squall Line A line of active thunderstorms, either continuous or with breaks, including contiguous precipitation areas resulting from the existence of the…
SRF (Surf Zone Forecast) - A National Weather Service routine or event driven forecast product geared toward non-boating marine users issued for an area…
SRH Storm-Relative Helicity
SRN Southern
SS Southshore
SSHS Saffir/Simpson Hurricane Scale
SST Sea Surface Temperature
ST Stratus
St Lawrence Freeze-Up Outlook A National Weather Service forecast product to keep mariners informed of the projected freeze-up date of ice the St. Lawrence River.
St. Elmo's Fire The glow on a masthead produced by an extreme buildup of electrical charge. Unprotected mariners should immediately move to shelter when this phenomena…
stability Tendency of systems, especially ecosystems, to persist, relatively unchanged, through time; also, persistence of a component of a system.
Stability Index The overall stability or instability of a sounding is sometimes conveniently expressed in the form of a single numerical value.
Stable Non-radioactive.
Stable air mass Stable air mass Air mass having static stability in its lower layers; it is free from convection, has a low degree of turbulence and may have stratiform…
Stable Boundary Layer The stably-stratified layer that forms at the surface and grows upward, usually at night or in winter, as heat is extracted from the atmosphere's base in…
Stable Core Post-sunrise, elevated remnant of the temperature inversion that has built up overnight within a valley.
stable isotope different species of an element that have the same atomic number, but different atomic mass, that are not affected by radioactive decay.
stable state a steady condition in which the recently observed behavior is expected to continue unchanged in the future.
Staccato Lightning A Cloud to Ground (CG) lightning discharge which appears as a single very bright, short-duration stroke, often with considerable branching.
Stage The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has…
Stair Stepping The process of continually updating river forecasts for the purpose of incorporating the effects rain that has fallen since the previous forecast was…
Standard Atmosphere A hypothetical vertical distribution of atmospheric temperature, pressure, and density that, by international agreement, is taken to be representative of…
Standard Synoptic Times The times of 0000, 0600, 1200, and 1800 UTC. Also known as the main synoptic times.
State Forecast Product This National Weather Service product is intended to give a good general picture of what weather may be expected in the state during the next 5 days.
State Weather Roundup This is a National Weather Service tabular product which provides routine hourly observations within the state through the National Weather Wire Service…
Station ID Five-digit WMO Station Identifier used by the Buoy Data Center since 1976. ID's can be reassigned to future deployments within the same 1 degree square.
Station Model A specified pattern for plotting, on a weather map, the meteorological symbols that represent the state of the weather at a particular observing station.
Station Pressure The absolute air pressure at a given reporting station. The air pressure is directly proportional to the combined weight of all air in the atmosphere…
Stationary Front A front between warm and cold air masses that is moving very slowly or not at all.
stationary pressure A front between warm and cold air masses that is moving very slowly or not at all.
STBL Stable
Steam Fog Fog formed when water vapor is added to air which is much colder than the source of the vapor.
Steepness In marine terms, on a buoy report, wave steepness is the ratio of wave height to wave length and is an indicator of wave stability.
Steering Currents Same as Steering Winds; a prevailing synoptic scale flow which governs the movement of smaller features embedded within it.
Steering flow Steering flow A basic fluid flow which exerts a strong influence upon the direction of movement of disturbances embedded in it.
Steering Winds Same as Steering Currents; A prevailing synoptic scale flow which governs the movement of smaller features embedded within it.
Steppe Habitat dominated by shrubs and grasses.
Stepped Leader A faint, negatively charged channel that emerges from the base of a thunderstorm and propagates toward the ground in a series of steps of about 1…
STFR Stratus Fractus
STG See Steam turbine generator