NCEP FNL Operational Model Global Tropospheric Analyses, July 1976 to April 1997

FNLs are analyses that are produced after the model has completed the forecast cycle, and they include the most complete set of observations available for a given cycle. The FNL from a given cycle, which is the best available analysis, is then used in the initialization of the next cycle.

FNL Data are available on pairs of 2.5-degree hemispheric grids (North and South) at the Earth's surface, twelve vertical levels from 1000 millibars up to 50 millibars, the tropopause, boundary and some sigma layers, and a few other levels. Parameters include surface pressure, sea level pressure, geopotential height, temperature, sea surface temperature, potential temperature, relative humidity, snow depth (weekly, Northern Hemisphere only) precipitable water, u- and v- winds, and vertical motion.