Generally, data related to a specific 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. Such data may be generated at either a centralized location or locally at the WSR-88D unit.
Airman's Meteorological advisory (WA)
An instrument that indicates the altitude of an object above a fixed level. Pressure altimeters use an aneroid barometer with a scale graduated in altitude instead of pressure.
Altimeter Setting
A correction of the station pressure to sea level used by aviation. This correction takes into account the standard variation of pressure with height and the influence of temperature variation with height on the pressure. The temperatures used correspond to the standard atmosphere temperatures between the surface and sea level.
An instrument used for measuring the speed of the wind.
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.
API Method
In hydrologic terms, a statistical method to estimate the amount of surface runoff which will occur from a basin from a given rainstorm based on the antecedent precipitation index, physical characteristics of the basin, time of year, storm duration, rainfall amount, and rainfall intensity.
An instrument that measures atmospheric pressure.
Barometric Pressure
The pressure of the atmosphere as indicated by a barometer.
The science of measuring depths of the oceans, lakes, seas, etc.
A device using a laser or other light source to determine the height of a cloud base. An optical ceilometer uses triangulation to determine the height of a spot of light projected onto the base of the cloud; a laser ceilometer determines the height by measuring the time required for a pulse of light to be scattered back from the cloud base.
Centimeter Burst
A solar radio burst in the centimeter wavelength range.
An instrument that measures angles of inclination; used to measure cloud ceiling heights.
Current Meter
In hydrologic terms, device used to measure the water velocity or current in a river.
Equipment that measures and records the size distribution of raindrops.
In hydrologic terms, an instrument which measures the evaporation rate of water into the atmosphere.
An inter­disci­plinary science involving the study and analysis of the inter­relation­ships between the atmo­spheric and land phases of water as it moves through the hydro­logic cycle.
A particle of condensed water (liquid, snow, ice, graupel, hail) in the atmosphere.
In hydrologic terms, individuals who have the combined knowledge in the fields of both meteorology and hydrology which enables them to study and solve hydrologic problems where meteorology is a factor.
An inter­disci­plinary science involving the study and analysis of the inter­relation­ships between the atmo­spheric and land phases of water as it moves through the hydro­logic cycle.
An instrument which measures the humidity of the air.
Atmospheric phenomena which affect the state of the atmosphere. They constitute dry particles that hang suspended in the atmosphere, such as dust, smoke, sand, and haze.
In hydrologic terms, a device to measure the quantity or rate of downward water movement through a block of soil usually undisturbed, or to collect such percolated water for analysis as to quality
Mercury Barometer
An instrument for measuring atmospheric pressure. The instrument contains an evacuated and graduated glass tube in which mercury rises or falls as the pressure of the atmosphere increases or decreases.
1) Meteorological

2) MOS (Model Output Statistics) guidance based on Environmental Modeling Centers ETA model
An international code (Aviation Routine Weather Report) used for reporting, recording and transmitting weather observations.
A graphical depiction of trends in meteorological variables such as temperature, dew point, wind speed and direction, pressure, etc. The time series meteogram can be constructed using observed data or forecast data.
Meteoric Water
Water derived from precipitation.
Meteorological Model Ensemble River Forecast (MMEFS)
An automated short-term hydrologic ensemble forecast system which utilizes temperature and precipitation output from the National Centers for Environmental Prediction (NCEP) GEFS and NAEFS meteorological models as inputs to River Forecast Center hydrologic models.
A person who studies meteorology. There are many different paths within the field of meteorology. For example, one could be a research meteorologist, radar meteorologist, climatologist, or operational meteorologist.
The science dealing with the atmosphere and its phenomena. A distinction can be drawn between meteorology and climatology, the latter being primarily concerned with average, not actual, weather conditions.
Navigation Methods
In hydrologic terms, there are three basic methods of providing and managing inland waterways -
1) Run-of-the-River: no provision of upstream storage;
2) Slack-Water: locks and dams provide slack water or pools with adequate depth for the draft of heavy barges and area to prevent excessive velocities;
3) Canalization: in lieu of a series of dams on the river a canal with locks adjoins the river.
A subset of the group of evaluations that constitute each element of an observation.
In hydrologic terms, a laboratory instrument for determining permeability by measuring the discharge through a sample of the material when a known hydraulic head is applied.
In hydrologic terms, an instrument used to measure pressure head in a conduit, tank, soil, etc. They are used in dams to measure the level of saturation.
Pressure Altimeter
An aneroid barometer calibrated to indicate altitude in feet instead of units of pressure. It is read accurately only in a standard atmosphere and when the correct altimeter setting is used.
An instrument used to measure the water vapor content of the air; a hygrometer consisting essentially of two similar thermometers with the bulb of one being kept wet so that the cooling that results from evaporation makes it register a lower temperature than the dry one and with the difference between the readings constituting a measure of the dryness of the atmosphere
Radar Meteorology
Branch of meteorology that uses radars for weather observations and forecasts.
(Relative Ionospheric Opacity meter). A specially designed radio receiver for continuous monitoring of cosmic noise. The absorption of cosmic noise in the polar regions is very sensitive to the solar low-energy cosmic ray flux
Significant Meteorological Advisory
Sling Psychrometer
An instrument used to measure the water vapor content of the atmosphere in which wet and dry bulb thermometers are mounted on a frame connected to a handle at one end by means of a bearing or a length of chain. The psychrometer is whirled by hand to provide the necessary ventilation to evaporate water from the wet bulb.
Symmetric Double Eye
A concentrated ring of convection that develops outside the eye wall in symmetric, mature hurricanes. The ring then propagates inward and leads to a double-eye. Eventually, the inner eye wall dissipates while the outer intensifies and moves inward.
An instrument for measuring air temperature.
A medium-range (3 to 7 day) numerical weather prediction model operated by the United Kingdom METeorological Agency. It has a resolution of 75 kilometers and covers the entire northern hemisphere. Forecasters use this model along with the ECMWF and GFS in making their extended forecasts (3 to 7 days).
Visible Infra-Red Imaging Radiometer (VIIRS)
A medium-resolution sensor flown aboard the NOAA-20 and Suomi-NP satellites.

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