Definitions
Wind vane
a device that measure wind direction
Cirrus
Cloud type that appears feathery or wispy, “curl of hair”, form in very high altitudes and made of ice crystals
Air pressure
the force exerted onto a surface by the weight of the air.
Barometer
an instrument measuring atmospheric pressure
Stratus
Cloud type that forms in flat layers when air cools over a large area, “spread out”, tend to produce steady, light precipitation
Jet stream
- a narrow, variable band of very strong, predominantly westerly air currents encircling the globe several miles above the earth.
Cumulus
Cloud type that appears as puffy masses and often look like cotton balls, “heap” or “pile”, usually appear in the daytime in fair weather but if they keep growing taller can produce rain showers and thunderstorms
Cold front
The forward edge of an advancing mass of cold air that pushes under a mass of warm air. Cold fronts often cause heavy precipitation and/or thunderstorms.
Nimbus
Clouds that produce precipitation; example: stratonimbus or cumulonimbus
Radar (Doppler)
a radar tracking system using the Doppler effect to determine the location and velocity of a storm, clouds, precipitation
Coriolis (force) effect
- The rotation of the Earth causes winds to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
Warm front
The forward edge of an advancing mass of warm air that rises over and replaces a retreating mass of cooler air. Warm fronts often cause steady precipitation.
Convection
the movement caused within a fluid (like air) by warmer, less dense material to rise, and colder, denser material to sink, resulting in heat transfer
Psychrometer
an instrument used to measure humidity