Subj : Wx Terms (N)(3) To : All From : Daryl Stout Date : Sat Jul 15 2017 12:07 am Non-Uniform Sky Condition A localized sky condition which varies from that reported in the body of the report. Non-Uniform Visibility A localized visibility which varies from that reported in the body of the report. Nonattainment Area An area that does not meet ambient air quality standards. Normal The long-term average value of a meteorological paramater (i.e., temperature, humidity, etc.) for a certain area. For example, "temperatures are normal for this time of year" means that temperatures are at or near the average climatological value for the given date. Normals are usually taken from data averaged over a 30-year period (e.g., 1971-2000 average), and are concerned with the distribution of data within limits of common occurrence. Normal Water Surface Elevation In hydrologic terms, the lowest crest level of overflow on a reservoir with a fixed overflow level (spillway crest elevation). For a reservoir whose outflow is controlled wholly or partly by movable gates, siphons, or other means, it is the maximum level to which water may rise under normal operating conditions, exclusive of any provision for flood surcharge. Normal Year A year during which the precipitation or stream flow approximates the average for a long period of record. North Atlantic Oscillation (Abbrev. NAO) - the NAO is a large-scale fluctuation in atmospheric pressure between the subtropical high pressure system located near the Azores in the Atlantic Ocean and the sub-polar low pressure system near Iceland and is quantified in the NAO Index. The surface pressure drives surface winds and wintertime storms from west to east across the North Atlantic affecting climate from New England to western Europe as far eastward as central Siberia and eastern Mediterranean and southward to West Africa. North Pacific High A semi-permanent, subtropical area of high pressure in the North Pacific Ocean. It is strongest in the Northern Hemispheric summer and is displaced towards the equator during the winter when the Aleutian Low becomes more dominate. Comparable systems are the Azores High and the Bermuda High. North Wall The north side boundary of the Gulf Stream generally extending northeast from Cape Hatteras where the Gulf Stream turns northeast. Northern Lights Common name for Aurora Borealis; the luminous, radiant emission from the upper atmosphere over middle and high latitudes, and centred around the earth's magnetic poles. These silent fireworks are often seen on clear winter nights in a variety of shapes and colours. Nor'easter A strong low pressure system that affects the Mid Atlantic and New England States. It can form over land or over the coastal waters. These winter weather events are notorious for producing heavy snow, rain, and tremendous waves that crash onto Atlantic beaches, often causing beach erosion and structural damage. Wind gusts associated with these storms can exceed hurricane force in intensity. A nor'easter gets its name from the continuously strong northeasterly winds blowing in from the ocean ahead of the storm and over the coastal areas. Nowcast A short-term weather forecast, generally out to six hours or less. This is also called a Short Term Forecast. NR Near NRN Northern NRW Narrow NS Nimbostratus- A cloud of the class characterized by a formless layer that is almost uniformly dark gray; a rain cloud of the layer type, of low altitude, usually below 8000 ft (2400 m). NSSFC National Severe Storm Forecast Center NSSL National Severe Storms Laboratory - this is one of NOAA's internationally known Environmental Research Laboratories, leading the way in investigations of all aspects of severe weather. Headquartered in Norman OK with staff in Colorado, Nevada, Washington, Utah, and Wisconsin, the people of NSSL, in partnership with the National Weather Service, are dedicated to improving severe weather warnings and forecasts in order to save lives and reduce property damage. Numerical Forecasting A computer forecast or prediction based on equations governing the motions and the forces affecting motion of fluids. The equations are based, or initialized, on specified weather or climate conditions at a certain place and time. Numerical Weather Prediction Same as Numerical Forecasting; a computer forecast or prediction based on equations governing the motions and the forces affecting motion of fluids. The equations are based, or initialized, on specified weather or climate conditions at a certain place and time. Numerous A National Weather Service convective precipitation descriptor for a 60 or 70 percent chance of measurable precipitation (0.01 inch). NVA Negative Vorticity Advection - the advection of lower values of vorticity into an area. NW Northwest NWD Northward NWLY Northwesterly NWP Numerical Weather Prediction NWR NOAA Weather Radio - "the voice of the National Weather Service" - NOAA Weather Radio broadcasts National Weather Service warnings, watches, forecasts and other hazard information 24 hours a day. It is provided as a public service by NOAA. The NOAA Weather Radio network has more than 480 stations in the 50 states and near adjacent coastal waters, Puerto Rico, the U.S. Virgin Islands and U.S. Pacific Territories. It is found from 162.40 to 162.55 Megahertz on the Public Service Band. NWRD Northwestward NWRN Northwestern NWS National Weather Service. An agency of the Federal Government within the Department of Commerce, National Oceanic and Atmospheric Administration, which is responsible for providing observations, forecasts and warnings of meteorological and hydrological events in the interest of national safety and economy. NWSH National Weather Service Headquarters NWSO National Weather Service Office NXT Next --- þ Synchronet þ The Thunderbolt BBS - wx1der.dyndns.org .