Weather
Sources of weather and oceanographic data
The data referenced below is available from Saildocs, Great Circle or Expedition. These are the main sources of data used by the sailing community and are all available in Expedition. In addition, much data is feely available on the internet.
Data available includes:
GFS, UM, ICON, ECMWF HRES & Ensemble, GDPS, Arpège, NBM,
Arome, HRRR, ICON-EU, ICON-DE,
Copernicus Mercator, OFS.
Expedition also supports several other services and has links to freely available observation and model data (MyGrib and MyImage).
Saildocs is a free source of grib data designed to satisfy Rule 41(c) and can be used to retrieve other information.
Great Circle - Squid is a complete weather service with satellite images, observations and model data
Offical supplier to the Volvo Ocean Race.
Important note
Whilst racing, services such as routing or weather data that is not free of charge or easily available to all boats are not allowed by Rule 41(c) (outside help) of the RRS. See Case 120 in the Case book.
Case 120 clarifies that rule 41c may be changed for any particular race by the notice of race and sailing instructions.
Weather maps and observations
Weather maps, satellite and radar imagery are available from many sources, including MyImage in Expedition, Rainviewer and Squid.
Weather observations are available from many sources, including BOM, NOAA NDBC and SailFlow in Expedition.
Global Rainviewer radar data
Integrated into Expedition
Rainviewer is a free service, so we encourage people to support them with Patreon
SailFlow is a source of weather observation data
Integrated into Expedition
Flowx is a very nice app and includes Expedition WRF data
Windy may be the best of the online weather viewers
Ensemble forecasts
Ensemble forecasts are used to help understand uncertainty in forecasts
Ensemble forecasts consist of an unperturbed control run and a set of perturbed members, in which the initial conditions and model physics are perturbed from the control run.
On average, each of the perturbed members will have lower skill than the control or deterministic forecast, although any individual forecast might show a higher skill.
Grib data
Data and sources we have found useful over many years of racing:
Global models
From experience, 0.25° is a good compromise for global model data offshore
0.5° is usually too coarse, but is an option for slow connections.
1/8°-1/10° data may be more useful, but file sizes will be larger. Doubling the resolution will increase file size by about a factor of 4
The Expedition server update status can be queried from within Expedition.
| 00z | 06z | 12z | 18z | |
|---|---|---|---|---|
| ICON | 0310 | 0910 | 1510 | 2110 |
| GFS | 0410 | 1010 | 1610 | 2210 |
| Arpège | 0400 | 1045 | 1530 | 2245 |
| GDPS | 0430 | 1630 | ||
| UM | 0450 | 1050 | 1650 | 2250 |
| ECMWF | 0710 | 1310 | 1910 | 0110 |
| ECMWF Ensemble | 0810 | 1410 | 2010 | 0210 |
| NBM | 0150 | 0850 | 1350 | 2050 |
| Mercator | 1000 |
Available 4x daily at 1/9° or 1/4° resolution to 384 hours
13km resolution and 127 levels
GEFS is the GFS ensemble forecast system
NOAA USA
Available 4x daily at about 1/10° resolution
00 & 12z runs are available to 168 hours, 06 & 18z runs to 60 hours
10km resolution and 70 levels
UK Met Office - Powered by Met Office Data
Available 4x daily at 1/4° or 1/8° resolution
00 & 12z runs are available to 180 hours, 06 & 18z runs to 120 hours
13km resolution and 90 levels
ICON data is generally available earlier than GFS and UM
DWD Germany
Licence and copyright
Available 4x daily at 0.4° resolution
00 & 12z runs are available to 240 hours, 06 & 18z runs to 90 hours
9km resolution and 137 levels
The ECMWF Ensemble forecast consists of a control and 50 perturbed members.
Licence and copyright
- Copyright statement: Copyright "© European Centre for Medium-Range Weather Forecasts (ECMWF)".
- Source www.ecmwf.int
- Licence Statement: This data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0). https://creativecommons.org/licenses/by/4.0/
- Disclaimer: ECMWF does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use.
- Where applicable, an indication if the material has been modified and an indication of previous modifications.
Available twice daily at 0.15° resolution to 240 hours
15 km resolution and 84 levels
Environment and Climate Change Canada, licence terms
Available 4x daily at 1/2° resolution globally and 1/10° for Europe
Available to 60, 72, 102 or 114 hours depending on run
7.5-37km resolution and 105 levels,
Meteo France
Licence
T681 (about 20km) and 60 levels
US Navy
Available 4x daily at about 10km resolution (NBM Oceanic)
NOAA USA
National Blend of Models - a blend of many models
Currently disabled as I don't believe it adds value
Regional models
Local government high resolution models are generally very good and are usually the default choice
Expedition also provides WRF simulations for areas where high resolution data is not available or hard to obtain. They can be also useful as a second forecast for comparison.
Oceanography
Copernicus Marine Environment Monitoring Service (CMEMS)
Global ocean currents available at 1/12° resolution
Higher resolution data available for north west Europe and the Mediterranean
Licence and attribution
Ocean currents and sea temperature, available at 1/12° resolution
NOAA USA
Wave model
NOAA USA
BSH Baltic & North Sea tidal currents
Tidetech is a source of current and tide data
Reanalysis
Copernicus
Copernicus ERA5 hourly data on single levels from 1979 to present
ECMWF