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.

A synoptic code approved by the World Meteorological Organization in which the observable meteorological elements are encoded and transmitted in "words" of five numerical digits length. Often abbreviated synoptic code.

Programmable Read-Only Memory. Read-only memory which can be programmed by the user using a special hardware programmer.

In Jeffreys' classification, a wind for which the pressure force exactly balances the viscous force, in which the vertical transfers of momentum predominate.

A type of cooling-power anemometer based upon the principle that the time constant of a thermometer is a function of its ventilation.

A device used to hold liquid-in-glass maximum and minimum thermometers in the proper recording position inside an instrument shelter, and to permit them to be read and reset. See Townsend support.

American Standard Code for Information Interchange. A standard code used to represent data using 8 bits (7 data bits and I parity bit) per character.

A spring which is designed to achieve a fixed spring constant over a wide temperature range. Usually, this involves an alloy with high nickel content such as Ni-Span C. It is common for these springs to be stress relieved at elevated temperature after for ...

Wind with a speed between 34 and 40 knots (39 and 46 mph); Beaufort scale number 8.

In folklore, a name for wind.

A hypothetical body which absorbs some constant fraction, between zero and one, of all electromagnetic radiation incident upon it, which fraction is the absorptivity and is independent of wavelength. Compare to black body, white body.

The level at which ice crystals and snowflakes melt as they descend through the atmosphere.

An inert gas. A colorless, monatomic element which is found to occur in dry air to the extent of only 0.000524 percent by volume. Helium is very light, having a molecular weight of only 4.003 and specific gravity referred to air of 0.138. Because helium i ...

A rainbow seen in the spray of the ocean. It is optically the same phenomenon as the ordinary rainbow.

Amount of water, expressed as a depth or as a mass, which would be obtained if all the water vapor in a specified column of the atmosphere were condensed and precipitated.

A recording hair hygrometer.

A series of Nansen-bottle water samples and associated temperature observations resulting from one release of a messenger.

Sustained winds greater than or equal to 40 mph or gust greater than or equal to 58 mph.

A generic term for any machine that enables a human being to communicate with a computer.

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