Module 13 - Meteorology
Shipping Forecast Terminology
The Met Office issues the Shipping Forecast four times daily for 31 sea areas around and approaching the British Isles. Each issue gives any gale warnings, a general synopsis and area forecasts. Read the printed issue time and valid period before interpreting the compressed wording; a recording or cached page can otherwise sound current when it is not.
Wind direction names where the wind comes from. Veering is a clockwise change, such as southwest to west; backing is anticlockwise. Force numbers describe the forecast wind range. ‘Imminent’ means within six hours of issue, ‘soon’ means six to 12 hours from issue, and ‘later’ means more than 12 hours from issue within the forecast period.
The visibility categories are very poor below 1,000 metres, poor from 1,000 metres to 2 nautical miles, moderate from 2 to 5 nautical miles, and good above 5 nautical miles. ‘Fog’ may appear as a weather description, but the official visibility category below 1,000 metres is ‘very poor’. Sea-state words also have ranges: smooth is below 0.5 m, moderate is 1.25–2.5 m and rough is 2.5–4 m.
| Term | Defined meaning | Decision cue |
|---|---|---|
| Veering / backing | Clockwise / anticlockwise wind-direction change | Work out the new exposure and point of sail |
| Imminent | Within 6 hours of issue | May affect the early passage |
| Soon | 6–12 hours after issue | Compare with the route timetable |
| Later | More than 12 hours after issue | Check whether the vessel will still be exposed |
| Very poor | Visibility below 1,000 m | Plan for restricted visibility and greater navigation workload |
| Poor / moderate / good | 1,000 m–2 M / 2–5 M / above 5 M | Relate the range to lookout, pilotage and traffic |
| Smooth / moderate / rough sea | Below 0.5 m / 1.25–2.5 m / 2.5–4 m | Apply vessel, tide, fetch and route context |
Optional quick check
Section 3 of 6
A forecast issued at 0500 UTC says conditions will change ‘soon’. Which window does that mean?
Sources and factual review
Reviewed 19 August 2026 - Day Skipper Revision.
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