Pertaining to rain, or more broadly, to precipitation.

Instrument for measuring the depth to which the soil is frozen.

A thermometer consisting of a clock mechanism the speed of which is a function of temperature.

Water condensed onto objects at or near the ground, due to the fact that their temperatures have fallen below the dew point temperature of the surrounding air, but not below freezing.

In radiometry, a measure of the intrinsic radiant intensity emitted by a radiator in a given direction.

Ice crystal deposits formed by sublimation (conversion of water vapor directly to ice) when temperature and dew point are below freezing.

An instrument which measures the intensity of radiation by determining the amount of chemical change( or fluorescence produced by that radiation.

In folklore, a name for rain.

Forecasting weather by the use of numerical models, run on high speed computers. Most of the NWP for the National Weather Service is done at the National Centers for Environmental Prediction (NCEP).

Ragged low clouds, usually stratus fractus. Most often applied when such clouds are moving rapidly beneath a layer of nimbostratus.

That portion of the atmosphere which is above the lower troposphere. Generally applied to levels above 850 mb.

Of equal or constant pressure, with respect to either space or time.

A measure of the intensity of gusts given by the ratio of the total range of wind speed between gusts and the intermediate periods of lighter wind to the mean wind speed, averaged over both gusts and lulls.

A white disk 12" or more in diameter which is lowered into the sea to estimate transparency of the water. The depths are noted at which it first disappears when lowered and reappears when raised.

See instrument error, observational error. random error, standard error, systematic error.

A severe weather condition characterized by low temperatures and strong winds bearing a great amount of snow, either falling or picked up from the ground.

The statement that the viscosity of air is independent of the density of air.

Thermometer used for measuring the lowest temperature attained during a given interval of time, for example, a day.

In a radiosonde observation, a level (other than a standard level) for which values of pressure, temperature, and humidity are reported because temperature and/or humidity data at that level is sufficiently important or unusual to warrant the attention of ...

A component of the wind (often using Cartesian coordinates. i.e. X and Y wind vectors). Also, an arrow representing wind velocity, drawn to point in the direction of the wind and with a length proportional to wind speed.