The indicating part of an instrument. For example, the hand of a watch or the meniscus of a mercury column.

pattern barometer-Mercurial barometer with a fixed scale and cistern and which therefore requires only one adjustment before each reading.

Same as luminous intensity.

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.

Diffuse solar radiation which has the same intensity in all directions.

Integrated Flood Observing and Warning System. National Weather Service flood warning program.

A plastic molding component formed by the reaction of phenol and formaldehyde. It can be heavily reinforced or "filled" with glass fibers or other materials. Phenolics are known for their high impact strength, excellent wear characteristics, and dimension ...

The measuring, transmitting, receiving, and indicating apparatus for obtaining the value of a quantity at a distance.

Same as wave pole.

A rainbow of angular radius of about 50

A thermometer used in aircraft which automatically corrects for adiabatic and frictional temperature rises by imparting a rotary motion to the air passing the thermal sensing element.

Thermodynamic change of state of a system in which there is transfer of heat across the boundaries of the system. Compare to adiabatic process.

Name applied to a class of instruments which measure the liquid content of the atmosphere.

An elongated area of relatively high pressure. Usually associated with and most clearly identified as an area of maximum anticyclonic curvature of the wind flow. The opposite of a trough.

The wind speed and direction at various levels in the atmosphere above the level reached by surface weather observations.

Closed, curved, flexible tube of elliptic cross section which is deformed, according to type, by variations of atmosphere spheric pressure or temperature and so provides a measurement of the particular parameter.

Clouds which cover between 6/10 and 9/10 of the sky. See Sky Terminology.

Temperature assumed by an unsaturated air parcel when brought adiabatically to a standard pressure (1,000 mb).

An instrument, located at the surface observing station, which is used to record the data presented by a radiosonde aloft.

A defective maximum thermometer of the liquid-inglass type in which the mercury flows too freely through the constriction. Such a thermometer will indicate a maximum temperature that is too low.