Fossil fuelSolid, liquid or gaseous fuels formed in the ground after millions of years by chemical and physical changes in plant and animal residues under high…
Fossil fuel combustionBurning of coal, oil (including gasoline), or natural gas. This burning, usually to generate energy, releases carbon dioxide, as well as combustion by…
FountainheadThe upper end of a confined-aquifer conduit, where it intersects the land surface.
FractocumulusA cumulus cloud presenting a ragged, shredded appearance, as if torn.
FractostratusA stratus cloud presenting a ragged, shredded appearance, as if torn. It differs from a fractocumulus cloud in having a smaller vertical extent and darker…
Fracture ZoneAn area which has a great number of fractures.
FracturingDeformation process whereby ice is permanently deformed, and fracture occurs.
FractusRagged, detached cloud fragments; same as scud.
Frazil IceFine spicules, plates, or discoids of ice suspended in water. In rivers and lakes, frazil is formed in supercooled, turbulent water.
Frazil SlushAn agglomerate of loosely packed frazil which floats or accumulates under the ice cover.
Freak WaveA wave of much greater height and steepness than other waves in the prevailing sea or swell system. See Rogue Wave.
Free AtmosphereThe part of the atmosphere that lies above the frictional influence of the earth's surface.
Free Ground WaterUnconfined ground water whose upper boundary is a free water table.
FreeboardPortion of the dam above spillway level to protect the dam against washout.
FreezeA freeze is when the surface air temperature is expected to be 32°F or below over a widespread area for a climatologically significant period of time.
Freeze WarningIssued during the growing season when surface temperatures are expected to drop below freezing over a large area for an extended period of time…
Freezeup dateDate on which the water body was first observed to be completely frozen over.
Freezing DrizzleA drizzle that falls as a liquid but freezes into glaze or rime upon contact with the cold ground or surface structures.
Freezing Drizzle AdvisoryIssued when freezing rain or freezing drizzle is forecast but a significant accumulation is not expected.
Freezing FogA suspension of numerous minute ice crystals in the air, or water droplets at temperatures below 0º Celsius, based at the Earth's surface, which…
Freezing LevelThe altitude at which the air temperature first drops below freezing.
Freezing RainRain that falls as a liquid but freezes into glaze upon contact with the ground.
Freezing Rain AdvisoryIssued when freezing rain or freezing drizzle is forecast but a significant accumulation is not expected.
Freezing SprayAn accumulation of freezing water droplets on a vessel caused by some appropriate combination of cold water, wind, cold air temperature, and vessel…
Freezing Spray AdvisoryAn advisory that may be issued within the Offshore Waters Forecast, the Coastal Waters Forecast, the Nearshore Marine Forecast, and the Open Lake Forecast…
Freezup jamIce jam formed as frazil ice accumulates and thickens.
French DrainA covered ditch containing a layer of fitted or loose stone or other pervious material.
FreonA registered trademark for a cholorfluorocarbon (CFC) gas that is highly stable and that has been historically used as a refrigerant.
Freshetthe annual spring rise of streams in cold climates as a result of snow melt; freshet also refers to a flood caused by rain or melting snow.
freshwaterA term referring to bodies of water that do not have salt.
FrictionResistance to motion when one body is sliding or tending to slide over another.
Friction HeadThe energy lost from the movement of a fluid in a conduit (pipe) due to the disturbances created by the contact of the moving fluid with the surfaces of…
Friction LayerSame as Planetary Boundary Layer; the layer within the atmosphere between the earth's surface and 1 km above the surface; this is the layer where friction…
friction velocityA measure of the surface stress reflecting the effects of surface roughness and wind velocity.
Frontal InversionA temperature inversion that develops aloft when warm air overruns the cold air behind a front.
Frontogenesis1. The initial formation of a front or frontal zone. 2. In general, an increase in the horizontal gradient of an airmass property, principally density…
Frost(Abbrev. FRST) - Frost describes the formation of thin ice crystals on the ground or other surfaces in the form of scales, needles, feathers, or fans.
Frost AdvisoryIssued during the growing season when widespread frost formation is expected over an extensive area.
FTPMAILAn Internet server application which provides access to Internet FTP server files via e-mail.
Fugitive DustThe dust released from any source other than a definable point source such as stack, chimney, or vent.
Fugitive emissionsUnintended gas leaks from the processing, transmission, and/or transportation of fossil fuels, CFCs from refrigeration leaks, SF6 from electrical power…
Fujita ScaleThe official classification system for tornado damage. The scale ranges from F0 (gale tornado, minor damage, winds up to 72 mph) to F5 (devastating…
Fujiwhara EffectA binary interaction where tropical cyclones within a certain distance (300-750 nm depending on the sizes of the cyclones) of each other begin to rotate…
Full-Physics Numerical ModelA computer model used to calculate air pollution concentrations. A full-physics numerical model uses a full set of equations describing the thermodynamic…
FumigationA pattern of plume dispersion produced when a convective boundary layer grows upward into a plume trapped in a stable layer.
Funnel CloudA condensation funnel extending from the base of a towering cumulus or Cb, associated with a rotating column of air that is not in contact with the ground…
FunnellingThe process whereby wind is forced to flow through a narrow opening between adjacent land areas, resulting in increased wind speed.
FusionThe combining of lighter elements into heavier ones. For lighter elements (e.g., hydrogen, helium) this process releases energy.
Gage(1) A device for indicating the magnitude or position of a thing in specific units, when such magnitude or position undergoes change, for example: The…
Gage DatumThe arbitrary zero datum elevation which all stage measurements are made from.
Gaging StationA particular site on a stream, canal, lake, or reservoir where systematic observations of hydrologic data are obtained.
GaleAn extratropical low or an area of sustained surface winds of 34 (39 mph) to 47 knots (54 mph).
Gale WarningA warning of sustained surface winds, or frequent gusts, in the range of 34 knots (39 mph) to 47 knots (54 mph) inclusive, either predicted or occurring…
GalleryA passageway within the body of a dam, its foundation, or abutments used for inspection, foundation grouting, and/or drainage.
GammaA unit of magnetic field intensity equal to 1 x 10.0-5 Gauss; also equal to 1 nanotelsa (nT).
Gamma RayA type of high-energy radiation that is different from an x-ray.
Gap WindsStrong winds channeled through gaps in the Pacific coastal ranges, blowing out into the Pacific Ocean or into the waterways of the Inside Passage.
Gas LawsThe thermodynamic laws pertaining to perfect gases, including Boyle's law, Charles' law, Dalton's law and the equation of state.
GasoholA registered trademark of an agency of the state of Nebraska, for an automotive fuel containing a blend of 10 percent ethanol and 90 percent gasoline.
gastropoda member of the class of mollusks that includes snails.
GateA device that controls the flow in a conduit, pipe, or tunnel without obstructing any portion of the waterway when in the fully open position.
GaugeAn instrument, usually mounted on the dashboard, used to monitor engine conditions such as fuel pressure, oil pressure and temperature, water pressure and…
GaussThe unit of magnetic field intensity equal to 1 dyne per unit pole.
Gaussian Plume ModelA computer model used to calculate air pollution concentrations. The model assumes that a pollutant plume is carried downwind from its emission source by…
Gaussian Puff ModelA model used to calculate air pollution concentrations. The model assumes that a continuously emitted plume or instantaneous cloud of pollutants can be…
GDROn a buoy report, direction, in degrees clockwise from true North, of the GSP, reported at the last hourly 10-minute segment.
General AviationThat portion of civil aviation, which encompasses all facets of aviation except air carriers.
General CirculationThe totality of large-scale organized motion for the entire global atmosphere.
General Circulation ModelGeneral circulation model (GCM) Numerical representation of the atmosphere and its phenomena over the entire Earth, using the equations of motion and…
General Circulation Model (GCM)A global, three-dimensional computer model of the climate system which can be used to simulate human-induced climate change.
General Circulation Models(GCMs) - These computer simulations reproduce the Earth's weather patterns and can be used to predict change in the weather and climate.
general measurement strategyAn approach to collecting useful information to help the Science Team fulfill the project mission.
General WindLand management agency term for winds produced by synoptic-scale pressure systems on which smaller-scale or local convective winds are superimposed.