alertsliner.blogg.se

AOB At or below ASB Aviation Support Branch Atmospheric Boundary Layer Same as Boundary Layer - in general, a layer of air adjacent to a bounding surface. ANBURS Alphanumeric Backup Replacement System Aneroid Barometer An instrument for measuring atmospheric pressure in which a needle, attached to the top of an evacuated box, is deflected as changes in atmospheric pressure cause the top of the box to bend in or out.Īnnual Exceedance Probability (AEP) The probability that a stream reach will have a flow of a certain magnitude in any given year. Anabranch A diverging branch of a river which re-enters the main stream. Ambient Of the surrounding area or environment. Another variation of the same system is called a "Saskatchewan Screamer". This low pressure area is usually accompanied by light snow, strong winds, and colder temperatures.

Alberta Clipper A fast moving low pressure system that moves southeast out of Canadian Province of Alberta (southwest Canada) through the Plains, Midwest, and Great Lakes region usually during the winter. Albedo Reflectivity the fraction of radiation striking a surface that is reflected by that surface. Airborne Snow Survey Program In hydrologic terms, Center (NOHRSC) program that makes airborne snow water equivalent and soil moisture measurements over large areas of the country that are subject to severe and chronic snowmelt flooding. Air Transportable Mobile Unit A modularized transportable unit containing communications and observational equipment necessary to support a meteorologist preparing on-site forecasts at a wildfire or other incident. The term may be applied to a short stretch of stream or conduit, or to a pond or reservoir. AFB Air Force Base Afterbay In hydrologic terms, the tail race of a hydroelectric power plant at the outlet of the turbines. Advanced Baseline Imager (ABI) A moderate resolution imaging system on the GOES and Himawari family of satellites. Adiabatic Process A process which occurs with no exchange of heat between a system and its environment. For parcels that remain unsaturated during lifting, the (dry adiabatic) lapse rate is 9.8☌ per kilometer. Adiabatic Lapse Rate The rate of decrease of temperature experienced by a parcel of air when it is lifted in the atmosphere under the restriction that it cannot exchange heat with its environment. Adiabatic Changes in temperature caused by the expansion (cooling) or compression (warming) of a body of air as it rises or descends in the atmosphere, with no exchange of heat with the surrounding air. Adiabat A line on a thermodynamic chart relating the pressure and temperature of a substance (such as air) that is undergoing a transformation in which no heat is exchanged with its environment. Such data may be generated at either a centralized location or locally at the WSR-88D unit. These data may consist of meteorological or hydrological parameters or of geographic boundaries, political boundaries, system configuration, telephone numbers (auto dial), or other like data. ABV Above ADAPTATION (ADAPTABLE) PARAMETER Generally, data related to a specific WSR-88D unit. Abutment Seeping Reservoir water that moves through seams or pores in the natural abutment material and exits as seepage. Right and left abutments are those on respective sides of an observer looking downstream. ABT About Abutment The part of a valley or canyon wall against which a dam is constructed. Absorption The process in which incident radiant energy is retained by a substance by conversion to some other form of energy. ABNDT Abundant Absolutely Stable Air An atmospheric condition that exists when the environmental lapse rate is less than the moist adiabatic lapse rate.Ībsolutely Unstable Air An atmospheric condition that exists when the environmental lapse rate is greater than the dry adiabatic lapse rate. Ablation Depletion of snow and ice by melting and evaporation.

This area is important for understanding surface weather, upper air storms tend to be steered in the direction of the winds at this level and are highly correlated with surface weather. Level of the atmosphere at which half the mass of the atmosphere lies above and half below, as measured in pressure units.

NOAA's National Weather Service - Glossary 500 mb Pressure surface (geopotential height) in the troposphere equivalent to about 18,000 feet above sea level.