Yachtmaster Offshore Standard: Weather Evidence and Action

The RYA theory scope includes taking and interpreting forecasts, plotting weather systems and making weather predictions with a barometer; the practical examination may assess meteorology as part of skippering. Written revision can rehearse the evidence and decision structure, but it cannot demonstrate live observation, vessel handling, crew leadership or command competence.

Start with an evidence ledger: source, warning status, issue time, valid period, forecast area, expected sequence and limits. Add observations at stated times — calibrated pressure, wind, cloud, visibility, temperature and sea state — and distinguish a measured fact from an interpretation. An app icon or remembered phrase without its issue and validity is not a defensible forecast record.

Compare expected and observed sequences. A front, trough or local effect may be consistent with several cues, but one pressure change, cloud type or wind shift does not prove the diagnosis. Pressure tendency and wind timing do not by themselves prove which system is present. When sources or observations disagree, name the conflict and act for the safer credible case while obtaining a fresh official forecast or warning.

Translate the weather into passage consequences: lee shore, wind against tide, harbour exposure, pilotage workload, speed loss, daylight, crew fatigue and refuge access. Set triggers before the exposed leg, such as a pressure tendency, wind or sea state, visibility, crew state, latest diversion time or minimum arrival margin. The trigger exists to create action, not merely another note in the log.

Close the loop with a short brief: facts, uncertainty, action now, roles, fallback and the exact evidence that can reopen the original route. The MCA advises checking the weather before departure, obtaining regular updates on longer trips and considering refuge if conditions deteriorate. All values below are fictional revision data; use current official and local information and the vessel's procedures for a real passage.