Module 13 - Meteorology
Sources of Weather Information
What you will learn
Build a resilient source chain for coastal and offshore passages, choosing products by area and purpose while retaining a route to updates if one channel fails.
No single app or broadcast covers every need. Use the relevant marine forecast and warnings, then add independent delivery and onboard observation.
The Inshore Waters Forecast covers UK coastal waters out to 12 nautical miles; the Shipping Forecast covers larger named sea areas. Their different scales mean neither is automatically ‘better’: choose the product that covers the route, and consult both when a passage crosses their boundaries.
MCA Maritime Safety Information can be delivered by NAVTEX, VHF and other services. International NAVTEX on 518 kHz carries English-language MSI; the UK national 490 kHz service includes inshore forecasts and coastal observations. Receiver set-up, message categories, range and local schedules still need checking.
BBC broadcast schedules and platforms can change: the dedicated long-wave service ended in 2024, leaving fewer FM broadcasts. Verify the current broadcaster or Met Office schedule rather than memorising an old timetable. For resilience, brief how the yacht will receive warnings and updates if mobile data, one app or one receiver fails.
| Source | Best use | Boundary to check |
|---|---|---|
| Inshore Waters Forecast | UK coast out to 12 M | Area, valid period and local exposure |
| Shipping Forecast | Named sea-area overview | Broad area may hide coastal detail |
| NAVTEX/MSI | Warnings and text information at sea | Frequency, categories, station and schedule |
| Online chart or imagery | Synoptic and observed corroboration | Source, issue/valid time and connectivity |
| Onboard observations | Detecting actual local trend | Instrument and observation limits |
Build a source chain that survives one failure
A passage starts within 12 miles of the coast, crosses an exposed sea-area boundary and ends beyond reliable mobile data.
1. Before departure
Obtain current Inshore Waters and relevant Shipping Forecast information with warnings and valid times.
2. Choose delivery
Confirm NAVTEX or other MSI reception and the local VHF or broadcaster schedule.
3. Cross-check
Use a current chart or imagery product and onboard pressure, wind, cloud and visibility.
4. Plan failure
Name the backup if mobile data, one app or one receiver becomes unavailable.
Sense check: Three apps fed by the same model or internet connection are not three independent sources.
Common mistake or limitation
- Choosing the Inshore Waters or Shipping Forecast by habit rather than route coverage.
- Treating several displays of the same data chain as independent confirmation.
- Memorising a broadcast time without checking whether the platform and schedule are current.
Recap
- Choose each product by route coverage and purpose.
- Use an independent delivery path and onboard observations.
- Verify current schedules; do not rely on obsolete long-wave timings.
Optional quick check
Section 13 of 15
Which source plan is most resilient for an exposed coastal passage?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Practice weather decisions
The meteorology module links forecasts, Beaufort force, pressure systems, fronts, and practical passage choices.