Abbreviation for precipitation effectiveness index.

The elevation of the water surface in a stream as measured by a river gauge with reference to some arbitrarily selected zero datum.

Based upon damage patterns, classifies twisters into six categories of wind speed (F0 thru F5), ranging from 40 to 318 mph estimated wind speed.

The distance or length of flow of the air past a point during a given interval of time.

As used by the U.S. Army Corps of Engineers, the departure (in

Part of a computer word that has meaning in itself, often, a byte.

An instrument used to measure changes in the level of the water in an evaporation pan. The gauge is normally placed in a Stillwell and adjusted so that the point of the hook just breaks the water surface. The change in water level is read on the attached ...

See evaporation pan.

A pressure-operated switching device used in a radiosonde. In operation, the expansion of an aneroid capsule causes an electrical contact to scan a radiosonde commutator composed of conductors separated by insulators.

A unit measure of electrical conduction. The facility with which a substance conducts electricity, as represented by the current density per unit electrical-potential gradient in the direction of flow. Electrical conductivity is the reciprocal of electric ...

Liquid water at temperatures colder than freezing.

Same as instrument shelter.

A hydrometeor consisting of a visible aggregate of minute water droplets suspended in the atmosphere near the earth's surface. Fog differs from cloud only in that the base of fog is at the earth's surface while clouds are above the surface.

An instrument for the measurement of the net flux of downward and upward total (solar and terrestrial) radiation through a horizontal surface.

A common unit used in measurement of atmospheric pressure. Defined as that pressure exerted by a one-inch column of mercury at standard gravity and a temperature of 0'C.

Generally, an instrument designed to measure or estimate the blueness of the sky. See Linke-scale.

A thermometer with a muslin-covered bulb which is moistened. used to measure wet-bulb temperature.

That horizontal wind velocity at which the Coriolis acceleration exactly balances the horizontal pressure force. It is directed along contour lines or isobars.

The amount of precipitation captured by a rain gauge.

The difference between the air temperature and the dew-point. Also called dew-point deficit, dew-point depression.