Global Forecast System

The Global Forecast System (GFS) is global numerical weather prediction computer model run by NOAA. This mathematical model is run four times a day and produces forecasts up 16 days in advance, but with decreasing spatial and temporal resolution over time (it is widely accepted that beyond 7 days the forecast is little better than guesswork).

The model is run in two parts: the first part has a higher resolution and goes out to 180 hours (7 days) in the future, the second part runs from 180 to 384 hours (16 days) at a lower resolution. The resolution of the model varies in each part of the model: horizontally, it divides the surface of the earth into 35 or 70 kilometre grid squares; vertically, it divides the atmosphere into 64 layers and temporally, it produces a forecast for every 3rd hour for the first 180 hours, after that they are produced for every 12th hour.

This is the only global model for which all output is [http://www.arl.noaa.gov/ready/cmet.html available] , for free, over the internet (as a result of U.S. law), and as such is the basis for most web based forecast services, e.g., Weather Underground, AccuWeather, The Weather Channel, [http://www.metcheck.com MetCheck] , [http://expert.weatheronline.co.uk/ Weatheronline] , [http://www.theweatheroutlook.com TheWeatherOutlook.] and [http://www.weather.com.au Weather.com.au]

External links

* [http://www.emc.ncep.noaa.gov/modelinfo/ GFS Model Info]