AMC1 MET.OR.200(b)
Meteorological reports and other information
ED Decision 2022/004/R
SPECI
Where required, SPECI should be issued whenever changes when the following criteria are met:
(a) when the mean surface wind direction has changed by 60° or more from that given in the latest report, the mean speed before and/or after the change being 10 kt or more;
(b) when the mean surface wind speed has changed by 10 kt or more from that given in the latest local report;
(c) when the variation from the mean surface wind speed (gusts) has changed by 10 kt or more from that at the time of the latest local report, the mean speed before and/or after the change being 15 kt or more;
(d) when the onset, cessation or change in intensity of any of the following weather phenomena occurs:
(1) freezing precipitation;
(2) moderate or heavy precipitation, including showers thereof; and
(3) thunderstorm, with precipitation;
(e) when the onset or cessation of any of the following weather phenomena occurs:
(1) freezing fog;
(2) thunderstorm, without precipitation;
(f) when the amount of a cloud layer below 1 500 ft (450 m) changes:
(1) from scattered (SCT) or less to broken (BKN) or overcast (OVC); or
(2) from BKN or OVC to SCT or less.
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