<p>From this page: <a href="https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gfs.php" rel="nofollow noreferrer">https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gfs.php</a></p>
<p>As I understand, The Global Data Assimilation System (GDAS) is just that, an assimilation system. It takes in real-world data from sensors across the globe and bins it into a regular grid. It is used then as an input or starting guess to the Global Forecast System (GFS). Because it is using real-world data, it only works going up to the current time.</p>
<p>The GFS takes the GDAS as a starting point, and then using physics equations and other methods it forecasts what conditions will be like hours or days from the starting point.</p>

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2024-05-17T18:20:33.100Z
2024-05-17T18:20:33.100Z
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<p>What is the exact difference between GFS 0.25 and GDAS 0.25 data which is available in <a href="http://nomads.ncep.noaa.gov/" rel="nofollow noreferrer">http://nomads.ncep.noaa.gov/</a>.</p>

<p>And are the GFS 0.5 and 1 degree data available in the above url and <a href="https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs" rel="nofollow noreferrer">here</a> the same?</p>

<meteorology><models><weather-forecasting><gfs>
Difference between GDAS and GFS data
Dry Fish
# Difference between GDAS and GFS data

(Asked by: username_0 on 2018-11-05)

What is the exact difference between GFS 0.25 and GDAS 0.25 data which is available in <http://nomads.ncep.noaa.gov/>.

And are the GFS 0.5 and 1 degree data available in the above url and [here](https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs) the same?

**Tags:** meteorology, models, weather-forecasting, gfs


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## 1 answers

### Answer by username_1 on 2024-05-17. Score: 1

From this page: <https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gfs.php>

As I understand, The Global Data Assimilation System (GDAS) is just that, an assimilation system. It takes in real-world data from sensors across the globe and bins it into a regular grid. It is used then as an input or starting guess to the Global Forecast System (GFS). Because it is using real-world data, it only works going up to the current time.

The GFS takes the GDAS as a starting point, and then using physics equations and other methods it forecasts what conditions will be like hours or days from the starting point.


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