Table 2. Cloud and Weather Type Definitions Used
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Shorthand Extended
Level notation Meaning Synoptic codes codes#
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Tcc total cloud cover N = 0-9 0-8
Clr completely clear sky N = 0
Ppt precipitation ww= 50-75,77,79,80-99
D drizzle 50-59
R rain 60-69
S snow 70-75,77,79
Ts thunderstorm,shower 80-99
Low CL=
Fg sky obscured by fog / with N=9 and ww=F* 11
St stratus 6,7
Sc stratocumulus 4,5,8
Cu cumulus 1,2
Cb cumulonimbus 3,9,
or N=9 with ww=Ts 10
Mid CM=
Ns nimbostratus 2,7, or N=9, with ww=DRS 12,11,10
/ with ww=DRS and CL=0,7 10
/ with ww= RS and CL=4-8 10
As altostratus 1; 2 if not DRS
Ac altocumulus 3,4,5,6,8,9; 7
High CH=
Cs cirrostratus 5,6,7,8
Cic cirrus, cirrocumulus 1,4,9
Cid dense cirrus 2,3
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# Extended codes shown where they differ from synoptic codes. In the extended code the
value "-1", rather than "/", is used to signify missing information.
* F represents the fog codes ww=10-12,40-49.