Weather Glossary - N
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Nacreous cloudClouds that have a soft, pearly lustre and form at altitudes of around 25-30 km. Also called mother-of-pearl clouds. |
Nautical mileThe distance of 1 minute of latitude. 1 nautical mile equals 1.85km. |
NCEPNational Centres for Environmental Prediction; the modernized version of NMC. |
Negative tilt troughAn upper level system which is tilted to the east with increasing latitude (i.e., with an axis from southeast to northwest). A negative-tilt trough often is a sign of a developing or intensifying system. |
NEXRADNEXt-Generation Weather RADar. Technologically-advanced weather radar being deployed to replace WSR-57 and WSR-74 units in the US. NEXRAD is a high-resolution Doppler radar with increased emphasis on automation, including use of algorithms and automated volume scan. NEXRAD units are known as WSR-88D. |
NGMNested Grid Model; one of the operational forecast models run at NCEP. The NGM is run twice daily, with forecast output out to 48 hours. |
NGP(NOGAPS) Operational forecast model run by the Fleet Numerical Meteorology and Oceanography Centre. Forecast output to 144 hours. The NOGAPS model is run primarily for operational use by the US Navy. |
Nimbostratus(Ns) Latin "nimbus" - violent rain, "stratus" - layer |
NitrogenThe most abundant gas in air, comprising 78% by volume. It is colourless and odourless. |
NMCNational Meteorological Centre (U.S.). |
NMOCNational Meteorological Operations Centre (Aus). Responsible for the operation of the Australian weather service, issuing real-time analysis and prediction products, maintaining a nation-wide weather watch and support the operational communications and computing infrastructure. |
NOAANational Oceanographic and Atmospheric Administration (U.S.). |
Noctilucent cloudsWavy, thin clouds that are seen at twilight in polar regions. They form at altitudes of 80-90 km and are made visible by sunlight reflecting off the underside of the cloud. |
NocturnalRelated to night-time, or occurring at night. |
NOGAPSSee NGP |
NowcastA short-term weather forecast, generally out to six hours or less. |
NSSLNational Severe Storms Laboratory, in Norman OK, USA. (Sometimes pronounced NES-sel.) |
NWPNumerical Weather Prediction. NWP uses simplified mathematical equations of motion to simulate various processes in the atmosphere. |
NWSNational Weather Service (U.S.). |
Weather News
Tropical cyclone watch declared for Gulf communities, system expected to strengthen
18:13 EDT
A cyclone watch is in place for Gulf of Carpentaria communities between Aurukun and Karumba, including Mornington Island, as a tropical low moves slowly towards the Queensland coast.
Unseasonal rain in South Australia
14:58 EDT
Several towns in SA saw on Monday their wettest day in months and the best January rainfall in decades.