How do I determine the layers of forecast clouds?
KBLV 051151Z 0512/0612 14005KT 8000 BR FEW030
WS010/18040KT QNH2960INS
TEMPO 0514/0516 21015G30KT 1600 TSRA BKN008CB OVC020
BECMG 0520/0521 30008KT 9999 SKC QNH2950INS T08/0518Z
TM01/0611Z
Cloud height is forecasted in hundreds of feet. Add two zeros to the end of
the value given. In this example, FEW030, BKN008CB, OVC020, and
SKC represent the values 3,000 few, 800 broken cumulonimbus, 2,000
overcast, and sky clear. Overseas locations may use the contraction
CAVOK (ceiling and visibility OK) when there is no significant weather,
the visibility is 10 km or greater, and the ceilings are greater than 5,000 ft.
In place of cloud layers, vertical visibility in hundreds of feet will appear
in a TAF cloud group when the sky is forecast to be totally obscured. For
example, VV002 represents a vertical visibility of 200 feet. Vertical
visibility in a TAF represents the forecast ceiling.
When a surface-based partial obscuration is forecasted, it will be encoded
as FEW000, SCT000, or BKN000 in the cloud layer area. A remark will
appear after the altimeter that will describe the phenomena responsible.
For example, FG SCT000 would indicate the weather element causing the
obscuration is caused by fog and the layer amount is SCT. Surface-based
partial obscurations will not be considered a ceiling.
Sky coverage (eighths):
* The lowest layer reported as broken or overcast constitutes a ―ceiling‖
A similar table can be found in Section C, ―METAR and TAF Code‖, of
the Flight Information Handbook.
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