8.3 Warnings
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1310 – Revised Joint IMO/IHO/WMO Manual on Maritime Safety Information (MSI) – (8 June 2009) - Annex - 8 – Meteorological Warnings and Forecasts - 8.3 Warnings

8.3 Warnings

  8.3.1 Warnings shall be given for gales (Beaufort force 8 or 9) and storms (Beaufort force 10 or over), and for tropical cyclones (hurricanes in the North Atlantic and eastern North Pacific, typhoons in the Western Pacific, cyclones in the Indian Ocean and cyclones of similar nature in other regions).

  8.3.2 The issue of warnings for near gales (Beaufort force 7) is optional.

  8.3.3 Warnings for gales, storms and tropical cyclones should have the following content and order of items:

  • .1 type of warning;

  • .2 date and time of reference in UTC,

  • .3 type of disturbance (e.g., low, hurricane, etc.) with a statement of central pressure in hectopascals;

  • .4 location of disturbance in terms of latitude and longitude or with reference to well-known landmarks;

  • .5 direction and speed of movement of disturbance;

  • .6 extent of affected area;

  • .7 wind speed or force and direction in the affected areas;

  • .8 sea and swell conditions in the affected area; and

  • .9 other appropriate information such as future positions of disturbance.

Sub-items .1, .2, .4, .6, and .7 listed above shall always be included in the warnings.

  8.3.4 When warnings are included for more than one pressure disturbance or system, the systems shall be described in a descending order of threat.

  8.3.5 Warnings shall be as brief as possible and, at the same time, clear and complete.

  8.3.6 The time of the last location of each tropical cyclone or extra-tropical storm shall be indicated in the warning.

  8.3.7 A warning shall be issued immediately the need becomes apparent and broadcasted immediately on receipt, followed by a repeat after six minutes, when issued as an unscheduled broadcast.

  8.3.8 When no warnings for gales, storms or tropical cyclones are to be issued, that fact shall be positively stated in part I of each weather and sea bulletin.

  8.3.9 Warnings shall be updated whenever necessary and then issued immediately.

  8.3.10 Warnings shall remain in force until amended or cancelled.

  8.3.11 Warnings issued as part I of a scheduled bulletin do not need to be repeated after 6 minutes.

  8.3.12 Warnings for other severe conditions such as poor visibility, severe sea states (such as high swell, risk of abnormal waves, etc.), ice accretion, etc., shall also be issued, as necessary.

Parent topic: 8 – Meteorological Warnings and Forecasts
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