Weather Words - Z | Weather | WGNTV.com | WGN TV

Weather Words - Z

-- Z --

Zenith: That spot in the sky, elevated 90° from all points on the observer's horizon, that lies directly above him.

Zeolite: In water terminology, ion-exchange materials used to soften water; natural or synthesized zeolites are silica compounds that remove calcium and magnesium from hard water and replace them with sodium.

Zephyr: A soft, gentle breeze. The name derives from Zephyros, the ancient Greek name for the west wind, a wind that is usually light and beneficial in Greece.

Zeus: In Greek mythology, the chief deity of the pantheon, a sky and weather god who was identical with the Roman god Jupiter. Zeus was regarded as the sender of thunder and lightning, rain and winds, and his traditional weapon was the thunderbolt.

Zigzag lightning: Lightning that appears to have a single channel (as opposed to a forked or branched structure), but the lightning channel is very irregular.

Zodiac: The strip of the sky about 9 degrees on either side of the ecliptic (the plane defined by the orbit of the Earth around the sun); the collection of constellations that lies within the zodiac band.

Zonal flow: The movement of upper winds along a latitude circle. In the United States, the term refers to a weather situation in which upper westerly winds blow from coast to coast with little or no deviation.

Zonda: In Argentina, a hot wind applied to a hot, dry, often dusty wind that blows down the slopes of the Andes Mountains; also, a hot, humid north wind in the pampas region.

Zone of aeration: The comparatively dry soil or rock located between the ground surface and the top of the water table; the unsaturated zone of rock and soil above the water table.

Zone of maximum precipitation: In a mountainous region, the elevation at which annual precipitation is greatest. Precipitation increases with height up to a level above which moisture and cloudiness decrease, usually 3,500-7,000 feet.

Zone of saturation: The soil or rock below the water table. Pore spaces in the zone of saturation are filled with water, in contrast to the pore spaces above the water table which contain considerable air.

Zulu (Z) time: The colloquial identifier for Greenwich (England) Mean Time, the time zone designated as the prime meridian. To obtain Greenwich Mean Time (GMT), add five hours to Central Daylight Time and six hours to Central Standard Time. To convert GMT to CST, subtract six hours from GMT and to convert GMT to CDT, subtract five hours from GMT. Z time is also known as Universal Time (UT).