What Is GFS MOS?

GFS MOS is a suite of text-bulletin and graphical products developed and supported by MDL. Both product types include meteorolgical guidance for a suite of variables (Temperature, Dewpoint, Precipitation Amount, etc.). Station-based MOS provides guidance at meteorolgcial station locations (such as airports), while gridded MOS prodvides these products on a grid. Values are based on outputs of the Global Forecast System (GFS) numerical model, and then calibrated using the MOS technique, which was developed at MDL. The MOS equations relating model output to observations have been developed using over 1600 meteorological stations' observations.

Full suites of products are produced for short-range (6-72 hours in advance) and extended-range (24-192 hours in advance) forecasts for meteorological stations in the Continental United States, Alaska, Hawaii, Puerto Rico, the U.S. Virgin Islands, and a limited number of islands in the Pacific Ocean. These products are produced four (short-range) or two (extended-range) times each day. Additionally, limited suites of GFS MOS products are produced for River Forecast Centers, marine meteorological stations, and select stations in Canada.

MOS Ensemble forecast guidance was previously produced using perturbed runs of the GEFS. GEFS MOS was discontinued in April 2019. Users of this product should use NBM instead. 

For more detailed information on individual products, please see product pages.