Name given to the unit of pressure in the International System of Units (SI). Equal to 1 newton/meter2 or 0.01 millibar.

A basic equation in daytime visual range theory, relating the apparent luminance of a distant black object, the apparent luminance of the background sky above the horizon, and the extinction coefficient of the atmosphere, or the air layer near the ground. ...

Same as instrument shelter.

A local variation of the wind vector or any of its components in a given direction.

A colorless and odorless gaseous element. The lightest and apparently the most abundant chemical element in the universe. However, it is found only in trace quantities in the observable portion of our atmosphere, only about 0.00005 percent by volume of dr ...

Similar to the spectroheliograph, but used for visual instead of photographic purposes.

Snow shower, particularly of a very light and brief nature.

Same as parhelion.

A pressure tube anemometer, consisting of a pitot tube mounted on the windward end of a wind vane and a suitable manometer to measure the developed pressure and calibrated in units of wind.

An instrument for measuring differences of electric potential.

United Kingdom forecast model. (Available via AccuWeather.com Professional.)

An instrument which measures the instantaneous rate at which rain is falling on a given surface. Also called a rate-of-rainfall gauge.

Balance of the water resources of a region, comparing precipitation and inflow with outflow, evaporation, and accumulation.

An air-launched balloon designed to be released in the eye of a tropical cyclone, float within the eye at predetermined levels, and transmit radio signals for RDF positioning.

A general term for atmospheric water in any of its forms, i.e. clouds, fog, hail, ice crystals, rain.

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.

A relatively small-scale, upward moving current of air.

The minimum temperature shown by a minimum thermometer exposed in an open situation with its bulb at the level of the tops of the grass blades of short turf.

A rainbow of angular radius of about 50

An instrument used to measure the water vapor content of the air.