The Offshore App is designed for boats heading offshore with a need to download forecast GRIB files on a Iridium Go, Satellite, SSB or email connection.
To download GRIB files, weather routing and departure planning using a PC / Mac computer you need to use the PredictWind Offshore App which can be downloaded from here
- Move your green start waypoint, and your red destination waypoint to your desired locations.
- Anytime you adjust the route, the high resolution GRIB areas are automatically selected for that route. If desired, you can manually override this by deselecting or selecting these areas. Please note that the large 8km areas are only available in the Standard Package, and the smaller 1km areas in the Professional package.
- In addition, the GRIB offshore areas are also automatically set up when adjusting the route. Again you can manually override this area by dragging the corner of the GRIB box.
- Click on the download button.
- Select GRIB high resolution to download the high resolution GRIB files. You have the choice of just getting wind data, or all weather variables for a larger download. High resolution GRIB files are generally too large for downloading over a satellite link. You are best to get this detailed weather data using the weather routing tool in this situation.
- Select GRIB offshore to download a GRIB area for your Offshore passage. When downloading over a Satellite connection we recommend using All Models, 24 hour timestep, 5 days, 100km resolution, wind, rain and pressure. For more detailed data use the weather routing tool. Wave data is a large file, and takes time to extract so please be aware of this when downloading over a Satellite connection.
- Then Click Next , then Download All and then wait for your file to download.
- While the download is in progress you can click on the hide button, and view detailed weather routing data. Here we have Graphs, wind, summary, route, wave and current.
- Once the entire download is complete you will be able to view all the GRIB data that you have requested.
- Previous data that you have downloaded will be removed from the display, so that you are only viewing the most current forecast.
- The wind can be displayed in 3 formats - arrows with pressure contours lines, Wind Barbs with pressure contours including wind shading , and directional arrows with pressure contour lines including wind shading. All 3 formats show the same data, so you can choose your favorite format.
- To animate the GRIB file use the play button. You can also use the left/right arrows to manually animate the weather at your own pace. The date/time is shown in the timezone of your laptop next to the legend. In addition you can click on the animation time slider to jump to a specific day. For example Monday.
- You can switch between the forecast models by clicking on PWG/PWE/GFS/ECMWF to get a comparison of the top 4 weather models.
- In addition you can view rain/cloud/air temp/wave. If you have not downloaded air temperature as in this example the feature will be greyed out and not available.
- To view the high resolution GRIB areas click on GRIB high resolution. Only 1 high resolution GRIB area can be viewed at a time. Select this area by clicking on the yellow square. Please note that you can only view high resolution areas that you have downloaded, the yellow squares. The high resolution areas contain more data and therefore take a fraction longer to display.
Additional Weather Routing Tips
The weather routing is the best tool for updating your forecast along your passage. The file size is very small (only 6KB) so very quick to download. You should update the weather routing forecast every 12 hours when the forecast updates.
• You do not need to download any GRIB files for the weather routing to be calculated, as the processing is done on the PredictWind servers.
• Please note, the forecast will run for a maximum of 14 days. Beyond 14 days, the model forecast is not accurate.