World Area Forecast System (WAFS) help


The NWS Display of WAFS Grids for turbulence, icing, cumulonimbus, cloud, and wind speed is a graphical representation of the grids issued jointly by the World Area Forecast Centers (WAFCs) in the United States and United Kingdom. These grids are sanctioned by the International Civil Aviation Organization (ICAO) and the Federal Aviation Administration (FAA) for use in flight planning. They are available for various levels from forecast hours 6 to 36, in three hourly time steps, in GRIB2 format. This product provides users a way to display the grids at all levels and time steps via a web page with an interactive GIS display. Users are able to overlay multiple levels and forecast parameters and loop through the time range.

For more guidance on the grids themselves, use the Met Office information for the New WAFS data sets.


The purpose of the display is to provide a rudimentary way to visualize the WAFS Grids of turbulence, icing, cumulonimbus, cloud, and wind. This visualization is intended for users who need to check that their own display software is correctly decoding the GRIB2 files and properly displaying the gridded data in graphical format. It is also intended to serve as a common reference point for the NWS and its customers when discussing the WAFS forecast data.

The intended users are software vendors that design flight planning software, plus airline dispatchers and air traffic managers. The display will be available 24/7. It will be updated 4 times per day, following the completion of each GFS model run. It is also intended to serve as a common reference point for the NWS and its customers when discussing the WAFS forecast data.

The WAFS data display is a visualization of the WAFS aviation grids that allows users to view the fields on a global display. The gridded data is displayed as a multicolored image with a color coded legend to relate the colors to numerical values. The images are provided for each time step and level in the WAFS Grids displayed on a map background depicting the world’s countries and oceans. Additionally a map background of Flight Information Regions can be toggled on in the map options. The grids include:

  • Clear Air Turbulence (CAT) at 200, 250, 300, 350, and 400 mb. CAT values run frrom 0 to about 35. Vaues above 5 are visualized.
  • In-Cloud Turbulence (InCldTurb) at 400, 500, 600, and 700 mb. InCldTurb values run from 0 to ~.035. Values above .005 are visualized.
  • Icing at 500,600, 700, and 800 mb. Icing values run from 0 to about 1. Values above .7 are visualized.
  • Cumulonimbus (CB) horizontal extent and tops. CB horizontal extent values run from 0 to ~1 and reflect the amount of grid cell covered by CB. Values above .3 are visualized.
    CB tops values run from 0 to about 60,000 feet and show max tops of CBs. Values above 30,000 feet are visualized.
  • Wind Speed at 300, 400, 500, and 600 mb. Wind speed values run from 0 to about 170 knots. Values above 60 knots are visualized.

Select which layers are visible on the map with the layer selector button on the top right corner of the map. Change which parameters are displayed in the map options, and select Looping to automate scrolling through the 36 hour forecast. The time slider on the bottom displays what time the forecast is valid and product labels on the top left corner display what is visible on the graphic.

World Area Forecast Internet File System (WIFS)

WIFS is the World Area Forecast System (WAFS) Internet File Service, a service provided by the United States to support international flight operations. An account is required to use WIFS. For more information, including Eligibility Requirements, go to the Description section and review the WIFS Users Guide (Section 4) located in the Documents section.

Approved access is required to access WIFS data. If you have an account, access WIFS data here.


What has changed recently?

The entire site has been redesigned so almost everything is new. For information about the most recent updates, please see the change log.

How often do you update the website?

We fix critical bugs as soon as possible, and we deploy functional upgrades regularly. Please let us know if you find something that isn’t working.

Why is my URL link not working?

As part of the upgrade to the site, some pages were consolidated and some URL's have changed. Check out the link conversions to find what you are looking for. If you are still unable to find the information you are looking for, submit a question using the envelope in the top right.

Why can't I log in to my account?

Most features of do not require an account. If you are a pilot that previously had an to submit PIREPs, please log in with your old username and password and you will be asked to reset your password the first time you log in. If you recently signed up for a new account, please check your email (including spam folders) for a confirmation email and follow the steps listed in the email. If you are still unable to log in after following the steps in the confirmation email, please contact us for additional information.

Where is the METAR page?

The interactive Graphical Forecasts for Aviation observation tab displays METARs along with other current data including surface fronts and radar imagery. To view METARs alone, click on the Layers button at the top left corner of the map and deselect items you do not wish to view. Decoded METARs can be displayed by enabling the "decoded METARs" option in the Map Options under the gear icon on GFA.

Raw METAR data can be displayed by selecting the Products dropdown and selecting METAR data.

Where is the Satellite/Radar page?

Satellite and radar imagery are available on the observations tab of the interactive Graphical Forecasts for Aviation, that displays surface observations, imagery, fronts, and more in one place. Satellite imagery is an optional layer available from the layer selector in the upper right corner of the map. To display satellite or radr imagery alone, deselect items on the layer selector to simplify the display.

How do I submit PIREPs?

Please use the operational to submit PIREPs — this site is experimental. More information can be found found on the request page.

How do I access the Flight Path Tool?

The flight path tool is now embedded into the interactive Graphical Forecasts for Aviation map. Click on the route button along the right side of the map to open the display. Enter the airports to navigate, and select the product you wish to display from the dropdown. Watch a video on how to use the cross sections here.

Where is the HEMS (Helicopter Emergency Medical Services) tool?

The HEMS tool has been integrated into the interactive Graphical Forecasts for Aviation. Click on the helicopter button in the upper right part of the map to switch GFA from general aviation mode into low-altitude mode, which offers similar features as the HEMS tool.

What will happen to ADDS with this update

The ADDS static graphics are being phased out and replaced with the Graphical Forecasts for Aviation, which offers greater flexibility and configurability; some static graphics continue to be available for decision support. The ADDS Text Data Server has been succeeded by the Data API. Please let us know if you need assistance with the migration.

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