Weather terms starting with E

150 terms

E East
E REGION In solar-terrestrial terms, a daytime layer of the earth's ionosphere roughly between the altitudes of 85 and 140 km.
E-19, Report on River Gage Station A report to be completed every 5 - 10 years providing a complete history of a river station and all gages that have been used for public forecasts since…
E-19a, Abridged Report on River Gage Sta In hydrologic terms, an abridged version of an E-19, an E-19a updates the E-19 as additional information, or changes occur at the station during the…
E-3, Flood Stage Report A form that a Service Hydrologist/ Hydrology Focal Point completes to document the dates in which forecast points are above flood stage, as well as the…
E-5, Monthly Report of River and Flood c In hydrologic terms, a monthly narrative report covering flooding which occurred over the past month.
E-7, Flood Damage Report A report to be completed anytime there is reported flood damage or loss of life as a direct result of flooding.
Earth radiation Earth radiation (terrestrial radiation) The total infrared radiation emitted from the Earth's surface; to be carefully distinguished from effective…
Easterlies Any winds with components from the east.
Eastern North Pacific Basin The portion of the North Pacific Ocean east of 140W. The National Hurricane Center in Miami, Florida is responsible for tracking tropical cyclones in this…
Ebb Current The movement of a tidal current away form the coast or down an estuary.
EBND Eastbound
EBS Emergency Broadcast System
Eccentricity A dimensionless quantity describing the elliptical shape of a planet's orbit.
Echo Energy back scattered from a target (precipitation, clouds, etc.) and received by and displayed on a radar screen.
Echo Tops The height above ground of the center of the radar beam using the tilt, or scan, that contains the highest elevation where reflectivities greater than 18…
ECMF European Center for Meteorology Forecast model.
ECMWF European Center for Medium-Range Weather Forecasts. Operational references in forecast discussions typically refer to the ECMWF's medium-range numerical…
Economy The way a country manages its money and resources (such as workers and land) to produce, buy, and sell goods and services.
Ecosystem A complex ecological community or environment forming a functioning whole.
Eddy Circular current of water moving against the main current. See recirculation zone.
EDT Eastern Daylight Time
EFCT Effect
effective emissivity A correction factor, dependent on the radiational characteristics of the earth-atmosphere system, that permits application of black body radiation laws to…
Effective Porosity The ratio of the volume of a soil or rock mass that can be drained by gravity to the total volume of the mass.
Effective Precipitation 1) That part of the precipitation that produces runoff. 2) A weighted average of current and antecedent precipitation that is "effective" in correlating…
Effective Terrestrial Radiation The difference between upwelling infrared or terrestrial radiation emitted from the earth and the downwelling infrared radiation from the atmosphere
Effective Topography The topography as seen by an approaching flow, which may include not only the actual terrain but also cold air masses trapped within or adjacent to the…
Effluent Seepage Diffuse discharge of ground water to the ground surface.
Effluent Stream Any watercourse in which all, or a portion of the water volume came from the Phreatic zone, or zone of saturation by way of groundwater flow, or baseflow.
El Niño A warming of the ocean current along the coasts of Peru and Ecuador that is generally associated with dramatic changes in the weather patterns of the…
El NiÃ¯Â¿Â½ A climatic phenomenon occurring irregularly, but generally every 3 to 5 years. El NiÃ¯Â¿Â½s often first become evident during the Christmas season…
El NiÃ¯Â¿Â½ - Southern Oscillation (ENSO) El NiÃ¯Â¿Â½, in its original sense, is a warm water current that periodically flows along the coast of Ecuador and Peru, disrupting the local…
Electrons Tiny particle moving around outside the nucleus of an atom. Each electron has one unit of negative charge (-) and almost no mass.
element (EH-leh-ment) A basic part of a whole. In chemistry, refers to a simple substance that cannot be broken down into smaller parts or changed into another…
ELEV Elevation
Elevated Convection Convection occurring within an elevated layer, i.e., a layer in which the lowest portion is based above the earth's surface.
ELSW Elsewhere
ELY Easterly
Embankment An earth structure the top of which is higher than the adjoining surface. A shaped earth or rockfill dam.
EMBDD Embedded
EMC Environmental Modeling Center
Emergency Action Plan A predetermined plan of action to be taken to reduce the potential for property damage and loss of lives in an area affected by a dam break or excessive…
Emergency Services Evaluation of an emergency medical condition and treatment to keep the condition from getting worse.
Emerging Flux Region (EFR) In solar-terrestrial terms, an area on the sun where new magnetic flux is erupting.
Emission inventory A list of air pollutants emitted into a community's, state's, nation's, or the Earth's atmosphere in amounts per some unit time (e.g.
Emissions Waste substances released into the air or water.
Emissions coefficient/factor A unique value for scaling emissions to activity data in terms of a standard rate of emissions per unit of activity (e.g.
Emissions Factor A unique value for scaling emissions to activity data in terms of a standard rate of emissions per unit of activity (e.g.
Emissivity The ratio of the radiant energy (heat) leaving (being emitted by) a surface to that of a black body at the same temperature and with the same area…
emittance The rate at which a black body radiates energy across all wavelengths.
EML Elevated Mixed Layer
Endemic Where disease occurs on a consistent basis.
ENDG Ending
Energy The capability of doing work; different forms of energy can be converted to other forms, but the total amount of energy remains the same.
Energy conservation Reduction or elimination of unnecessary energy use and waste. See energy-efficiency.
Energy Dissipator A device constructed in a waterway to reduce the kinetic energy of fast flowing water. See stilling basin.
Energy Efficiency Using less energy to achieve the same outcome. For example, better insulation would enable a home to stay warm utilizing less energy.
Energy Helicity Index An index that incorporates vertical shear and instability, designed for the purpose of forecasting supercell thunderstorms
Energy Intensity The relative extent that energy is required for a process.
Energy quality Ability of a form of energy to do useful work. High-temperature heat and the chemical energy in fossil fuels and nuclear fuels are concentrated high…
Engineer's Level A telescope which is attached to a spirit-tube level, all revolving around a vertical axis and is mounted on a tripod.
Engineering Change Order (ECO) An engineering task or project directly resulting from an Engineering Change Request.
Engineering Change Request (ECR) A method of formally requesting that a change be made to the infrastructure. This change can be to a particular instrument, data system, data process…
Engineering Work Request (EWR) Used to request engineering resources, as soon as possible, when operational, science, or engineering needs require a quick engineering response where no…
Enhanced Greenhouse Effect The concept that the natural greenhouse effect has been enhanced by anthropogenic emissions of greenhouse gases.
Enhanced oil recovery Removal of some of the heavy oil left in an oil well after primary and secondary recovery. See primary oil recovery, secondary oil recovery.
Enhanced V A pattern seen on satellite infrared photographs of thunderstorms, in which a thunderstorm anvil exhibits a V-shaped region of colder cloud tops extending…
Enhanced Wording 1. An option used by the SPC in tornado and severe thunderstorm watches when the potential for strong/violent tornadoes, or unusually widespread damaging…
ENHNCD Enhanced
ENSEMBLE A collection of numerical model results that show slightly different possible outcomes.
Ensemble Forecast Multiple predictions from an ensemble of slightly different initial conditions and/or various versions of models.
Ensemble Hydrologic Forecasting A process whereby a continuous hydrologic model is successively executed several times for the same forecast period by use of varied data input scenarios…
Ensembles Reference to a set of computer models run under the concept of Ensemble Forecasting: multiple predictions from an ensemble of models with slightly…
ENSO Abbreviation for El Niño-Southern Oscillation, a reference to the state of the Southern Oscillation.
ENSO Diagnostic Discussion The CPC issues the ENSO Diagnostic Discussion around the middle of the month. The discussion addresses the current oceanic and atmospheric conditions in…
Enteric fermentation A digestive process by which carbohydrates are broken down by microorganisms into simple molecules for absorption into the bloodstream of an animal.
ENTR Entire
Entrainment The incorporation of fish, eggs, larvae, and other plankton with intake water flow entering and passing through a cooling water intake structure and into…
Entrainment Zone A shallow region at the top of a convective boundary layer where fluid is entrained into the growing boundary layer from the overlying fluid by the…
Entrance Region The region upstream from a wind speed maximum in a jet stream (jet max), in which air is approaching (entering) the region of maximum winds, and therefore…
Entropy A measure of the unavailable or unusable energy in a system; energy that cannot be converted to another form.
Environment All the natural and living things around us. The earth, air, weather, plants, and animals all make up our environment.
Environment Canada The Canadian federal government department responsible for issuing weather forecasts and weather warnings in Canada.
Environmental Lapse Rate The rate of decrease of air temperature with height, usually measured with a radiosonde.
Environmental Temperature Sounding An instantaneous or near-instantaneous sounding of temperature as a function of height.
EPA See Environmental Protection Agency.
EPCTG Expecting
EPV Equivalent Potential Vorticity
Equi-Potential Line A line, in a field of flow, such that the total head is the same for all points on the line, and therefore the direction of flow is perpendicular to the…
Equilibrium Drawdown The ultimate, constant drawdown for a steady rate of pumped discharge.
Equilibrium Level (EL) - On a sounding, the level above the level of free convection (LFC) at which the temperature of a rising air parcel again equals the temperature of…
Equilibrium Surface Discharge The steady rate of surface discharge which results from a long-continued, steady rate of net rainfall, with discharge rate equal to net rainfall rate.
Equilibrium Time The time when flow conditions become substantially equal to those corresponding to equilibrium discharge or equilibrium drawdown.
equilibrium vapor pressure The necessary vapor pressure around liquid water that allows the water to remain in equilibrium with its environment.
Equinox The two times of the year when the sun crosses the equator and night and day are of equal length; usually occurs on March 21st (spring equinox) and…
Equivalent Potential Temperature The equivalent potential temperature is the temperature a parcel at a specific pressure level and temperature would have if it were raised to 0 mb…
ERLY Early
ERN Eastern
Erosion The wearing away of land surface by wind or water, intensified by land-clearing practices related to farming, residential or industrial development, road…