The Nested Grid Model (usually known as NGM for short) was a numerical weather prediction model run by the National Centers for Environmental Prediction, a division of the National Weather Service, in the United States. The NGM was, as its name suggested, derived from two levels of grids: a hemispheric-scale grid and a synoptic-scale grid, the latter of which had a resolution of approximately 90 kilometers. Its most notable feature was that it assumed the hydrostatic equation.NCEP Nested Grid Model Overview
National Weather Service Southern Region Headquarters. Retrieved 2010-05-15. The NGM debuted in 1987, directly replacing the limited-area fine mesh (LFM) model, which was immediately halted upon the NGM's debut. The NGM was also used to create

model output statistics In weather forecasting, model output statistics (MOS) is a multiple linear regression technique in which predictands, often near-surface quantities (such as two-meter-above-ground-level air temperature, horizontal visibility, and wind directio ...

.Explanation of Current NGM MOS
National Weather Service Meteorological Development Lab (1999). Retrieved 2010-05-15. Development of the model stopped in 1993. By 2000, the model was seen as obsolete, particularly for mesoscale features that were not hydrostatic, and was scheduled to be superseded by the Global Forecast System (GFS) in 2001. However, though the NGM ceased widespread use in the early 2000s due to the GFS and improvements in the

Eta model Eta (uppercase , lowercase ; grc, ἦτα ''ē̂ta'' or ell, ήτα ''ita'' ) is the seventh letter of the Greek alphabet, representing the close front unrounded vowel . Originally denoting the voiceless glottal fricative in most dialects, ...

(later the North American Mesoscale Model), and the NGM's short-range LAMP products were phased out in 2006, NGM MOS products continued to be in significant general use (alongside the Eta/NAM and GFS) until March 3, 2009, when the NGM MOS products were discontinued.

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National Weather Service numerical models {{climate-stub