GFS meteorological Forecast 

Last update: May 2020

Introduction

The Global Forecast System (GFS) is a weather forecast model produced by the National Centers for Environmental Prediction (NCEP).

Dozens of atmospheric and land-soil variables are available worldwide, among which we selected a few parameters as listed in "output variables". This service delivers 0,25° spatial resolution. The data availability is from about a month ago up to day+3. GFS meteorological archives are available upon demand from 2019 up to day+3 in automatic access.

The manual access via the web service interface is free.

We provide an automatic access to the data. Please contact us for a quotation.

Inputs

  • Latitude and longitude: Enter the values in decimal degrees (3 or 4 digits after comma) or directly click on the map to select your point, or you can also use the "Search Address" tool on the top of the map.
  • Start date and End date: Format yyyy-mm-dd.
    Please pay attention to ask for complete months when asking for monthly values. If incomplete, the given monthly value results from an interpolation based on the selected days.
  • Time step: "1 min", "5 min", "10 min", "15 min", "30 min", "hour", "day", "week", or "month". NB: "1 min" and "5 min" time steps are limited to one month of data per delivery.
  • Output format: CSV only

 

Outputs

The output file format is CSV. When pushing the "process" button, wait a while and right-click on the appeared link to retrieve your file. Here is the output column content:

  • Temperature (K): Temperature at 2 m above ground in Kelvins (K)
  • Relative humidity (%): Relative humidity at 2 m above ground in percent (%)
  • Pressure (hPa): Pressure at ground level in hPa
  • Wind speed (m/s): Wind speed at 10 m above ground in m/s
  • Wind direction (deg): Wind direction at 10 m above ground in degrees (0 means from North, 90 from East...)
  • Rainfall (kg/m2): Rainfall (= rain depth in mm)
  • Snowfall (kg/m2): Snowfall
  • Snow depth (m): Snow depth in meters
  • Short-wave irradiation (wh/m2): Surface downward short-wave irradiation (broadband=GHI)

Correction of the temperature with the altitude

By default, the temperature is given for the altitude of GFS ( 0,25° spatial resolution), available in the 6th headerline entitled: "# Site altitude" in the retrieved output CSV file. It is possible to modulate the temperature with the actual altitude of the selected point with for instance the altitude contained in the Digital Elevation Model SRTM (approx. 100 m of spatial resolution) to take into account the decrease of temperature with height.

Here is the equation (Wikipedia): Temperature_corrected (C°) = Temperature (K) - 272.15 - 0.65*(Altitude_GFS - Altitude_SRTM)/100