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

Weather Words - N

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Nadir: The point of the celestial sphere that lies directly beneath the observer and diametrically opposite to the zenith, which is directly above.

Names for hurricanes: The custom of applying girls' names to tropical cyclones started in World War II, apparently suggested by George Stewart's novel "Storm" in which meteorologists at the San Francisco Weather Bureau office whimsically applied girls' names to storms in the Pacific.

National Climatic Data Center: The federal organization whose function is to store, publish and disseminate to the public all weather data gathered in the United States. It is located in Asheville, North Carolina. Telephone (704) 271-4800; web address: www.ncdc.noaa.gov

National Hurricane Center: (1) The National Hurricane Center, a unit of the Tropical Prediction Center located in Miami, Fla,. estimates that hurricane preparations cost more than $500,000 per mile of U.S. coastline put under a hurricane warning. (2) A unit in the National Weather Service whose mission is to save lives, mitigate property loss and improve economic efficiency by forecasting and warning of hazardous tropical weather.

National Weather Service: The federal agency within the U.S. Department of Commerce that provides weather, hydrologic, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy.

Naulu: In Hawaii, an intense shower.

Neon: A colorless, odorless, inert gaseous element that is a trace constituent of the atmosphere, amounting to only 0.0018 percent by volume of dry air.

Nephelococcygia: The tendency to see or to be reminded of familiar objects within the shape of a cloud.

Nephology: The study of clouds; the branch of meteorology that is concerned with cloud types, their formation, development and dissipation.

Neumann, John von: (1903-1957) Pioneering researcher who, with his team at the Institute for Advanced Study at Princeton, New Jersey, made the first computer weather forecast in 1950, thereby initiating the era of numerical weather prediction.

New Orleans: Nicknamed "The Big Easy". The U.S. city considered to be most at risk to hurricane storm surge. Much of the city lies below sea level behind levees and is kept dry only by pumping.

Nexrad: "NEXt generation weather RADar", a nationwide network of 120 Doppler radars being used by National Weather Service meteorologists to detect precipitation, to measure atmospheric motions and to issue warnings of severe weather.

NFL Championship Game lowest temperature: -13?F at gametime in Green Bay, Wisc., on Dec. 31, 1967. The Packers defeated the Dallas Cowboys 21-17 as 50,861 fans watched in Lambeau Field. The Packers went on to win the Super Bowl.

Niagara Falls: On March 30, 1848, the Niagara River and the falls ran dry. Ice floes in Lake Erie effectively dammed the river and stopped up the falls. By April 1, the river and falls had returned to normal.

Nighttime visibility: The greatest distance at which it is just possible to identify with the unaided eye a moderately intense unfocused light.

Nimbostratus: A low (usually less than 1,000 feet), uniformly gray, feebly-illuminated layer of clouds from which steady precipitation falls. Nimbostratus covers the entire sky and usually looks "wet".

Nimbostratus clouds: A low (usually less than 1,000 feet), uniformly gray, feebly-illuminated layer of clouds from which steady precipitation falls. Nimbostratus usually looks "wet", covers the entire sky.

Nimbus: A name for clouds that are producing precipitation. Because many different kinds of clouds produce precipitation, the term is no longer used in international cloud classification schemes.

Niphablepsia: The medical name for snow blindness (impaired vision or temporary blindness caused by sunlight reflected from snow surfaces). Symptoms of niphablepsia are a gritty sensation under the eyelids, excessive watering, double vision.

Nitrogen: A colorless, tasteless, gaseous element and the most abundant constituent of the atmosphere, amounting to 78.09 percent by volume of dry air.

NOAA: Acronym for the National Oceanic and Atmospheric Administration, an agency within the Commerce Department of the United States federal government and the parent agency of the National Weather Service.

NOAA Weather Radio: A network of 480-plus radio stations across the United States broadcasting continuous weather and hydrologic information from local forecast offices of the National Weather Service. Weather radio for metropolitan Chicago: KWO39 broadcasting on 162.55 MHz.

Noctilucent clouds: The highest of all clouds; ice-crystal clouds occurring at elevations of about 40-60 miles above the earth's surface. They can be seen after sunset when, because of their great height, they are still illuminated by sunlight.

Noctiphobia: The irrational or morbid fear of the night.

Nocturnal: Pertaining to the nighttime; occurring at night.

Nor'easter: A powerful low pressure system that moves north along the Atlantic Coast, so called because coastal winds are from the northeast, sometimes of gale force. Heavy rain and snow and high surf often occur.

Nor'easter: (1) Along the Atlantic coast, the name given to strong, steady winds from the northeast that are accompanied by inclement weather. It often occurs when a storm system moves up the U.S. Atlantic seaboard. (2) A powerful low pressure system that moves northward along the Atlantic Coast, so called because the winds along the coast are from the northeast, sometimes of gale force. Heavy rain and snow often occur.

Normal: The name given to the average value over a period of years (ideally, 30 years) of a variable such as temperature, pressure, rainfall or duration of sunshine at a location. The current 30-year period used for U.S. normals is 1961-1990.

Norte: A strong, cold wind that blows from the northeast in Mexico and on the shores of the Gulf of Mexico. It results from a wintertime outbreak of cold air from the north.

North America's lowest temperature: On Monday, February 3, 1947, the temperature at Snag, Yukon Territory, Canada, plunged to -81?F, establishing the lowest temperature ever recorded in North America.

Norther: In the southern U.S., especially Texas, a strong cold wind from the northwest, north or northeast. It is the cold outbreak associated with the southward movement of a frigid air mass.

Northern Hemisphere cold pole: The location in the Northern Hemisphere that has the hemisphere's lowest average annual temperature. It is usually placed at Verkhoiansk, Siberia, with an average annual temperature of +3 degrees F. Chicago's average annual temperature is 49 degrees.

Northern Hemisphere's coldest place: Verkhoiansk, Siberia, with an average annual temperature of +3 degrees (ranging from -59 degrees in January, +60 degrees in July). Chicago's average annual temperature is 49 degrees.

Northern lights: The aurora of the Northern Hemisphere (aurora borealis), a luminous phenomenon in the night sky consisting of overlapping curtains of green, white, red and blue light.

Northern lights frequency: Greatest around the autumnal equinox, but the aurora borealis can occur on 10-20 percent of nights each year in northern Minnesota and along the Canadian border.

November: The 11th month of the year and the last month of meteorological autumn. It is Chicago's fifth coldest and sixth driest month. Months that are colder: January, February, December, March.

November 23: In 1982, Hurricane Iwa struck the Hawaiian Islands with wind gusts above 130 m.p.h., including 81 m.p.h. at Honolulu.; in 1912, the freighter Rouse Simmons, "The Christmas Tree Ship," ferrying trees to Chicago, sank in a gale off Two Rivers, Wisc., claiming 17 lives.

November U.S. temperature extremes (U.S): A range of 158 degrees; highest: 105 degrees at Craftonville, Calif., on November 12, 1906; lowest: -53 degrees at Lincoln, Mont., on November 16, 1959.

November, 1870: The first month that U.S. weather observations were taken by the Weather Bureau (later the National Weather Service) and transmitted to Washington, D.C., for plotting on a national map.

Nuclear exoatmospheric burst: A nuclear explosion that occurs at an altitude high enough to be effectively outside the Earth's atmosphere. At this altitude, generally above 65 miles, the effects of the explosion on the Earth are minimal.

Nuclear winter: Possible severe global cooling following a nuclear war. The scenario envisions a chilled Earth enshrouded for months in smoke, dust and toxic fog. The term was coined by Richard Turco in 1983 in an article authored by Turco, Thomas Ackerman, James Pollard, Carl Sagan and Owen Toon.

Number of major U.S. hurricanes: Since 1900 (as of 2003), the United States coast from Texas to Maine has been struck by 66 major hurricanes (storms containing winds of at least 111 m.p.h.). That is an average of less than one (0.7) major hurricane per year.

Numerical weather prediction: Forecasting the future state of the atmosphere by the solution of governing sets of equations that describe atmospheric behavior, based on observed or assumed initial conditions. Many different numerical models of the atmosphere exist.

Nyctophobia: The irrational or morbid fear of darkness or the night.