Wind with a speed between 41 and 47 knots (47 and 54 mph); Beaufort scale number 9.

A type of pressure-plate anemometer in which the plate, restrained by a stiff spring, is held perpendicular to the wind. The wind-activated motion of the plate is measured electrically. The natural frequency of this system can be made high enough so that ...

A systematic summary of the terms (inflow, outflow, and storage) of the storage equation as applied to the computation of soil-moisture changes, ground-water changes, etc. An evaluation of the hydrologic balance of an area. Also called basin accounting, w ...

Same as water year.

See foehn.

Instrument for measuring the intensity of radiant energy. Its principle is based on the variation of electrical resistance, with the incoming radiation, of one or both the metallic strips which the instrument comprises.

Forecasting weather by the use of numerical models, run on high speed computers. Most of the NWP for the National Weather Service is done at the National Centers for Environmental Prediction (NCEP).

A device which converts energy from one form into another, i.e. an ac generator transducer which converts the mechanical motion of anemometer cups into an electrical signal.

Same as atmometer.

Same as humidity strip.

Wind with a speed between 4 and 27 knots (4 and 31 mph); Beaufort scale numbers 2 through 6.

A hygrometer which determines the amount of precipitable moisture in a given region of the atmosphere by measuring attenuation of radiant energy caused by the absorption bands of water vapor.

A graphical representation of stage or discharge at a point on a stream as a function of time.

Contraction for pilot balloon observation.

Same as instrument shelter.

The limiting values of ceiling, visibility, and wind, or runway visual range, established as safety minimum for aircraft landings and take-offs.

See photometer.

Any and all forms of water particles, liquid or solid, that fall from the atmosphere and reach the ground.

An instrument for the measurement of the rate of ice accretion on an unheated body.

Precipitation composed of liquid water drops more than 0.5 mm in diameter, failing in relatively straight, but not necessarily vertical, paths. Compare to drizzle.