See foehn.

Generally, the relative states of inflow, outflow, and storage of moisture over a given area of earth's surface.

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.

National Centers for Environmental Prediction. Central computer and communications facility of the National Weather Service; located in Washington, DC.

An optical instrument which consists of a sighting telescope mounted so that it is free to rotate around horizontal and vertical axes, with graduated scales so that the angles of rotation may be measured. Used to observe the motion of a pilot balloon.

Technically, the temperature registered by the dry-bulb thermometer of a psychrometer. However, it is identical with the temperature of the air and may also be used in that sense.

The record obtained from a bolometer.

Contraction for pilot balloon observation.

The difference between the solar radiation directed downward and upward; net flux of solar radiation.

Same as geostrophic wind level.

A radar term for a single pulse of radio energy.

One of several constant-pressure levels in the atmosphere for which a complete evaluation of data derived from upper air observations is required.

NEXt Generation RADar. A NWS network of about 140 Doppler radars operating nationwide.

A modification of the dew cell used in radiosonde equipment.

The distance that an observer can see vertically into a surface-based obscuring phenomenon such as fog, rain, or snow. The distance estimate must be based upon ceiling balloon ascensions or ceiling light projector measurements.

A rain gauge which automatically records the amount of precipitation collected, as a function of time.

A form of psychrometer with wet-bulb and dry-bulb thermometers mounted on opposite sides of a specialty designed graph of the psychrometric tables. It is so arranged that the intersections of two curves determined by the wet-bulb and dry-bulb readings -yi ...

The direction, with respect to true north, from which the wind is blowing. Distinguish from magnetic wind direction. In all standard upper-air and surface weather observations, it is true wind direction that is reported.

Apparatus consisting of (a) standard radiosonde and radiosonde ground equipment to obtain upper-air data on pressure, temperature, and humidity, and (b) a self-tracking radio direction-finder to provide the elevation and azimuth angles of the radiosonde s ...

A recording weight barometer.