Offshore Physical Environmental Guidelines
Appendix F - Marine Weather Reporting Notes
The following information is provided to assist with the implementation of the FM13 code.
Installations are particularly encouraged to include the maximum number of data groups in Section 2 of FM13.
Particular attention should be paid to code groups 1PwaPwaHwaHwa and 70HwaHwaHwa. These code groups are to be used when instrumental wave data is available. Code group 70HwaHwaHwa is to be used as well when instrumental wave data is available to an accuracy of 0.1 m.
Code group 2PwPwHwHw is only to be used when non-instrumented wind wave information is being reported.
These wave encode parameters may be found in code 3155 in WMO Publication 306 Volume 1 page I.1c-95.
Specific information on encoding important wave data is available in WMO Publication 306 Volume 1, page I.1-A-17.
Special Phenomena - Hurricane and Squall Winds
See also WMO Publication 306 Manual on Codes Volume II page II-4-A.1-2 section 4/12.14.2. The following group should be included by all stations when appropriate.
When, due to a hurricane or tropical storm, the maximum one-minute average wind speed between two times of observation exceeds 34 knots, the value of this maximum one-minute average wind speed should be included, together with the time of its occurrence, in the following form, added at the end of Section 3 of the synoptic report: ONE-MINUTE MAXIMUM . . . KNOTS AT . . . (hour, minute) UTC. A maximum two-minute average wind speed is acceptable providing the remark clearly indicates TWO-MINUTE MAXIMUM.
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