0 0 No change
1 1 Marked wind shift
2 2 Beginning or ending of marked turbulence
3 3 Marked temperature change (not with altitude)
4 4 Precipitation begins or ends
5 5 Change in cloud forms
6 6 For or ice fog bank begins or ends
7 7 Warm front
8 8 Cold front
9 9 Front, type not specified
15 15 Missing value
