Thanks for digging out that info. I looked at it and right on page 1 in bold type it says:
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Note: The United States does not report remarks in the same manner as the WMO standard.
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Why on earth not?
The page in question is misleading. There is no "WMO standard" for remarks, and in fact there's no obligation to transmit remarks internationally. The idea of a RMK is that it can be plain language -- some groups may have particular ways of structuring remarks, in the same way that there are conventions for how to structure comments in computer programs. But that doesn't make it incorrect, or even unhelpful, to use different conventions.