Meteorology and atmospheric science terminology · MLC-0110

Meteorology and atmospheric science terms: F (180)

• F1) Fahrenheit- The standard scale used to measure temperature in the United States. On this scale, the...
• F CoronaIn solar-terrestrial terms, of the white-light corona (that is, the corona seen by the eye at a total solar...
• F ScaleAbbreviation for Fujita Scale, a system of rating the intensity of tornadoes; for detailed information, see...
• FAForecast Area
• FAAFederal Aviation Administration
• FaceIn hydrologic terms, the external surface of a structure, such as the surface of a dam.
• FaculaIn solar-terrestrial terms, a bright region of the photosphere seen in white light, seldom visible except...
• Fahrenheit(abbrev. F) The standard scale used to measure temperature in the United States. On this scale, the freezing...
• fairIt is usually used at night to describe less than 3/8 opaque clouds, no precipitation, no extremes of...
• Fallthe season of the year which is the transition period from summer to winter occurring as the sun approaches...
• Fall LineA skiing term, indicating the line of steepest descent of a slope.
• fall windA strong, cold, downslope wind.
• FallstreakSame as Virga; streaks or wisps of precipitation falling from a cloud but evaporating before reaching the...
• FANAVN MOS Guidance (older version)
• fanningA pattern of plume dispersion in a stable atmosphere, in which the plume fans out in the horizontal and...
• FASTSTFastest
• fathomUnit of water depth equal to 6 feet.
• FAWSFlight Advisory Weather Service
• FBO(Great Lakes Freeze-Up/Break-Up Outlook) - A National Weather Service product to keep mariners informed of...
• FCSTForecast
• Federal Snow SamplerIn hydrologic terms, a snow sampler consisting of five or more sections of sampling tubes, one which has a...
• Feeder BandsLines or bands of low-level clouds that move (feed) into the updraft region of a thunderstorm, usually from...
• FEMAFederal Emergency Management Agency. An agency of the federal government having responsibilities in hazard...
• Ferrel cellIn the general circulation of the atmosphere, the name given to the middle latitude cell marked by sinking...
• fetch1. The area in which ocean waves are generated by the wind. Also refers to the length of the fetch area...
• FewA National Weather Service convective precipitation descriptor for a 10 percent chance of measurable...
• Few CloudsAn official sky cover classification for aviation weather observations, descriptive of a sky cover of 1/8 to...
• FFGFlash Flood Guidance
• FG(Also abbrev. F) - Fog - water droplets suspended in the air at the Earth's surface. Fog is often hazardous...
• FibrilIn solar-terrestrial terms, a linear pattern in the H-alpha chromosphere of the sun, as seen through an...
• Field (Moisture) CapacityThe amount of water held in soil against the pull of gravity
• Field Moisture DeficiencyThe quantity of water, which would be required to restore the soil moisture to field moisture capacity.
• FilamentA mass of gas suspended over the photosphere by magnetic fields and seen as dark lines threaded over the...
• Filament ChannelA broad pattern of fibrils in the chromosphere, marking where a filament may soon form or where a filament...
• Fill DamIn hydrologic terms, any dam constructed of excavated natural materials or of industrial wastes
• fillingThe opposite of deepening. A general increase in the central pressure of a low pressure system.
• Fire WindA thermally driven wind blowing radially inward toward a fire, produced by horizontal temperature differences...
• FirebrandAny source of heat, natural or man made, capable of igniting wildland fuels; flaming or glowing fuel...
• firn lineIn hydrologic terms, the highest level to which the fresh snow on a glacier's surface retreats during the...
• Firn (Snow)In hydrologic terms, old snow on top of glaciers, granular and compact and not yet converted into ice. It is...
• first law of thermodynamicsThe law of physics that states that the heat absorbed by a system either raises the internal energy of the...
• flanking lineA line of cumulus or towering cumulus clouds connected to and extending outward from the most active part of...
• FlareIn solar-terrestrial terms, a sudden eruption of energy on the solar disk lasting minutes to hours, from...
• flashA sudden, brief illumination of a conductive channel associated with lightning, which may contain multiple...
• Flash floodA rapid and extreme flow of high water into a normally dry area, or a rapid water level rise in a stream or...
• Flash Flood Guidance(FFG) Forecast guidance produced by the River Forecast Centers, often model output, specific to the potential...
• Flash Flood Statement(FFS) In hydrologic terms, a statement by the NWS which provides follow-up information on flash flood watches...
• Flash Flood TableIn hydrologic terms, a table of pre-computed forecast crest stage values for small streams for a variety of...
• Flash Flood WarningIssued to inform the public, emergency management, and other cooperating agencies that flash flooding is in...
• Flash Flood WatchIssued to indicate current or developing hydrologic conditions that are favorable for flash flooding in and...
• Flash MultiplicityThe number of return strokes in a lightning flash.
• FlashboardsIn hydrologic terms, a length of timber, concrete, or steel placed on the crest of a spillway to raise the...
• FLGFalling
• Float Recording Precipitation gageIn hydrologic terms, a rain gage where the rise of a float within the instrument with increasing rainfall is...
• FlocA cluster of frazil particles
• floeIn hydrologic terms, an accumulation of frazil flocs (also known as a "pan") or a single piece of broken ice
• floodAny high flow, overflow, or inundation by water which causes or threatens damage.
• Flood CategoriesTerms defined for each forecast point which describe or categorize the severity of flood impacts in the...
• Flood Control StorageIn hydrologic terms, storage of water in reservoirs to abate flood damage
• Flood CrestMaximum height of a flood wave as it passes a certain location.
• Flood Frequency CurveIn hydrologic terms, (1) A graph showing the number of times per year on the average, plotted as abscissa...
• Flood Hazard OutlookA high Level graphical depiction and key messages highlighting the potential threat of inland flood hazards...
• Flood Inundation MappingIn the context of the National Water Model (NWM) FIM, the expected maximum inundation extent over a...
• Flood Loss Reduction MeasuresIn hydrologic terms, the strategy for reducing flood losses. There are four basic strategies. They are...
• Flood of RecordIn hydrologic terms, the highest observed river stage or discharge at a given location during the period of...
• flood plainIn hydrologic terms, the portion of a river valley that has been inundated by the river during historic...
• Flood Potential Outlook(ESF on AFOS) (FPO for Acronym): In hydrologic terms, An NWS outlook that is issued to alert the public of...
• Flood PreventionIn hydrologic terms, measures that are taken in order to keep flood problems from getting worse. Planning...
• Flood ProblemsIn hydrologic terms, problems and damages that occur during a flood as a result of human development and...
• Flood ProfileIn hydrologic terms, a graph of elevation of the water surface of a river in flood, plotted as ordinate...
• flood routingIn hydrologic terms, process of determining progressively the timing, shape, and amplitude of a flood wave as...
• flood stageAn established gage height for a given location above which a rise in water surface level begins to create a...
• Flood StatementIn hydrologic terms, a statement issued by the NWS to inform the public of flooding along major streams in...
• flood warning(FLW) In hydrologic terms, a release by the NWS to inform the public of flooding along larger streams in...
• flood watchIssued to inform the public and cooperating agencies that current and developing hydrometeorological...
• flood waveIn hydrologic terms, a rise in streamflow to a crest and its subsequent recession caused by precipitation...
• Flooded IceIn hydrologic terms, ice which has been flooded by melt water or river water and is heavily loaded by water...
• FloodproofingIn hydrologic terms, the process of protecting a building from flood damage on site. Floodproofing can be...
• FloodwallIn hydrologic terms, a long, narrow concrete, or masonry embankment usually built to protect land from...
• FloodwayIn hydrologic terms, (1) A part of the flood plain, otherwise leveed, reserved for emergency diversion of...
• Flow(abbrev. FLW) Wind. In meteorology, a qualitative reference of an air parcel(s) with respect to its direction...
• Flow Duration CurveIn hydrologic terms, a cumulative frequency curve that shows the percentage of time that specified discharges...
• Flow SeparationThe process by which a separation eddy forms on the windward or leeward sides of bluff objects or steeply...
• Flow SplittingThe splitting of a stable airflow around a mountain barrier, with branches going around the left and right...
• Flowing WellIn hydrologic terms, a well drilled into a confined aquifer with enough hydraulic pressure for the water to...
• FLRYFlurry
• FLSRiver Flood Statement
• FluenceTime integrated flux
• FluidMatter which flows; gas or liquid.
• FlurriesSnow flurries are an intermittent light snowfall of short duration (generally light snow showers) with no...
• fluxThe rate of transfer of fluids, particles or energy per unit area across a given surface (amount of flow per...
• FLWFollow (or) Flow- Wind
• FMFrom or Fathom
• fMinIn solar-terrestrial terms, the lowest radiowave frequency that can be reflected from the ionosphere.
• FNTFront
• FNTGNSFrontogenesis
• FNTLYSFrontolysis
• foehnA warm, dry wind on the lee side of a mountain range, the warmth and dryness of the air being due to...
• foehn pauseA temporary cessation of the foehn at the ground due to the formation or intrusion of a cold air layer which...
• foEsIn solar-terrestrial terms, the maximum ordinary mode radiowave frequency capable of reflec- tion from the...
• foF2In solar-terrestrial terms, the maximum ordinary mode radiowave frequency capable of reflection from the F2...
• Fog(abbrev. F) Fog is water droplets suspended in the air at the Earth's surface. Fog is often hazardous when...
• FogbowA rainbow that has a white band that appears in fog, and is fringed with red on the outside and blue on the...
• Forced ChannelingChanneling of upper winds along a valley's axis when upper winds are diverted by the underlying topography...
• ForebayIn hydrologic terms, the water behind (upstream) of the dam.
• ForecastA statement of prediction.
• Forecast CrestIn hydrologic terms, the highest elevation of river level, or stage, expected during a specified storm event.
• Forecast GuidanceComputer-generated forecast materials used to assist the preparation of a forecast, such as numerical...
• Forecast Issuance StageThe stage which, when reached by a rising stream, represents the level where RFCs need to begin issuing...
• Forecast PeriodsOfficial definitions for NWS products:
• Forecast PointA location along a river or stream for which hydrologic forecast and warning services are provided by a WFO...
• Forecast valid forThe period of time the forecast is in effect beginning at a given day, date and time, and ending at a given...
• ForesightIn hydrologic terms, a sighting on a point of unknown elevation from an instrument of known elevation. To...
• Forward Flank DowndraftThe main region of downdraft in the forward, or leading, part of a supercell, where most of the heavy...
• FountainheadIn hydrologic terms, the upper end of a confined-aquifer conduit, where it intersects the land surface.
• FOUSForecast Output United States
• FPOFlood Potential Outlook
• FPSFujita-Pearson Scale
• FQTFrequent
• 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...
• FractureIn hydrologic terms, any break or rupture formed in an ice cover or floe due to deformation.
• Fracture ZoneIn hydrologic terms, an area which has a great number of fractures.
• FracturingIn hydrologic terms, deformation process whereby ice is permanently deformed, and fracture occurs.
• fractusRagged, detached cloud fragments; same as scud.
• frazil iceIn hydrologic terms, fine spicules, plates, or discoids of ice suspended in water. In rivers and lakes...
• Frazil SlushIn hydrologic terms, an 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...
• free atmosphereThe part of the atmosphere that lies above the frictional influence of the earth's surface.
• Free Ground WaterIn hydrologic terms, unconfined ground water whose upper boundary is a free water table
• FreeboardIn hydrologic terms, the vertical distance between the normal maximum level of the water surface in a...
• freezeA freeze is when the surface air temperature is expected to be 32°F or below over a widespread area for a...
• Freeze WarningIssued during the growing season when surface temperatures are expected to drop below freezing over a large...
• Freeze WatchThis product is issued when there is potential for significant, widespread freezing temperatures, but the...
• Freezeup dateIn hydrologic terms, the date 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...
• Freezing Drizzle AdvisoryIssued when freezing rain or freezing drizzle is forecast but a significant accumulation is not expected...
• freezing fogA fog the droplets of which freeze upon contact with exposed objects and form a coating of rime and/or glaze.
• Freezing Fog AdvisoryThis product is issued when very light ice accumulations are expected from freezing fog.
• 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...
• Freezing Spray AdvisoryAn advisory for an accumulation of freezing water droplets on a vessel at a rate of less than 2 centimeters...
• Freezup jamIn hydrologic terms, ice jam formed as frazil ice accumulates and thickens
• F-regionIn solar-terrestrial terms, the upper layer of the ionosphere, approximately 120 to 1500 km in altitude. The...
• French DrainIn hydrologic terms, an underground passageway for water through the interstices among stones placed loosely...
• freshetthe annual spring rise of streams in cold climates as a result of snow melt; freshet also refers to a flood...
• frictionThe mechanical resistive force of one object on another object's relative movement when in contact with the...
• friction headIn hydrologic terms, the decrease in total head caused by friction
• friction layerSame as Planetary Boundary Layer; the layer within the atmosphere between the earth's surface and 1 km above...
• FRMGForming
• frontA boundary or transition zone between two air masses of different density, and thus (usually) of different...
• 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...
• fropaFrontal Passage
• FROSFCFrontal Surface
• frost(Abbrev. FRST) - Frost describes the formation of thin ice crystals on the ground or other surfaces in the...
• Frost AdvisoryIssued during the growing season when widespread frost formation is expected over an extensive area. Surface...
• Frost PointDew point below freezing.
• FrostbiteHuman tissue damage caused by exposure to intense cold.
• Frozen DewWhen liquid dew changes into tiny beads of ice. This occurs when dew forms and temperatures later drop below...
• FRSTFrost- Frost describes the formation of thin ice crystals on the ground or other surfaces in the form of...
• FRZFreeze
• FRZNFrozen
• FSCBGA specific aerial spray dispersion model. The acronym comes from the names of the sponsor and developers...
• FTFeet (or foot)
• FTHRFurther
• FTPMAILAn Internet server application which provides access to Internet FTP server files via e-mail. The National...
• Fugitive DustDust that is not emitted from definable point sources such as industrial smokestacks. Sources include open...
• Fujita scale(or F Scale) - A scale of tornado intensity in which wind speeds are inferred from an analysis of wind damage:
• Fujiwhara effectA binary interaction where tropical cyclones within a certain distance (300-750 nm depending on the sizes of...
• Full-Physics Numerical ModelA computer model used to calculate air pollution concentrations. A full-physics numerical model uses a full...
• fumigationA pattern of plume dispersion produced when a convective boundary layer grows upward into a plume trapped in...
• funnel cloudA condensation funnel extending from the base of a towering cumulus or Cb, associated with a rotating column...
• FunnellingThe process whereby wind is forced to flow through a narrow opening between adjacent land areas, resulting in...
• FVTForecast Verification Tool
• FWCNGM MOS Guidance
• FWDForward
• FZRAfreezing rain

180 of 3,164 terms in Meteorology and atmospheric science terminology (MLC-0110). Request the full dataset.