Sources of weather and oceanographic data
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.
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, Rainviewer and Squid in Expedition.
Weather observations are available from many sources, including BOM, NOAA NDBC and SailFlow in Expedition.
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.
ENS is available from Expedition and GEFS is available from Great Circle.
Data we have found useful over many years of racing:
From experience, 0.25° is often a good compromise for global model data offshore
0.5° is usually too coarse, but is an option for slow connections,
0.1° data may be more useful, but file sizes will be larger,
Doubling the resolution will increase file size by about a factor of 4.
Most model data is available 3-4 hours after the main synoptic hours.
ICON is generally available first, followed by GFS, UM and the others.
See the approximate availability table below.
The Expedition server update status can be queried from within Expedition.
Local government high resolution models are generally very good and are usually the default choice.
Expedition also provides WRF simulations, mainly for sailing venues where high resolution forecast data is not available.
WRF, Cook Islands
Copernicus Marine Environment Monitoring Service (CMEMS)
Global ocean currents available at 1/12° resolution
Higher resolution data available for north west Europe, Mediterranean and Iberia to Ireland
Licence and attribution
Ocean currents and sea temperature, available at 1/12° resolution
BSH Baltic & North Sea tidal currents
Barotropic is a source of current and tide data for France
Current Lab is a source of current and tide data
Tidetech is a source of current and tide data
SHOM tidal currents for France
Licences and copyright