Navigational Warnings are provided by the NAVAREA ONE co-ordinator at the UK Hydrographic Office, Taunton. The primary means of disseminating this information is by NAVTEX and INMARSAT SAFETYNET. However, WZ navigational warnings are also broadcast on VHF and MF on selected aerials, on receipt and at four hourly intervals (see broadcast schedules). Negative Tidal Surge Warnings are issued as a WZ on receipt, and at hourly intervals until absorbed into the next regular broadcast.
International Code of Signals - WZ = What are the forecast sea conditions in my area (or area around lat ... long...)?
This is usually answered with XA = true direction of sea (in tens of degrees) is expected to be ... and then XB = The sea state is expected to be ... followed by a number between 0 (calm, glossy) and 9 (Phenomenal, over 14m high).