Page 61 - AFMAN 15-111, 12 MAR 2019

AFMAN15-111 12 MARCH 2019 61

11.5. Manual Observing Methods. The legacy Qualification Training Package Observing –
Trainer’s Guide, found on the AFWKC and the WMO-No. 407 International Cloud Atlas, Volume
II both contain references and photographs for identifying the various cloud forms and can be used
as a resource when determining significant cloud types and amounts. Sky condition will be
evaluated in all METAR and SPECI observations. (T-1).

11.5.1. All layers visible from the point of observation are considered in sky cover reports. A
maximum of six layers may be reported. When more than six layers are present, use Table
11.2 to determine reporting priority.
11.5.2. When observed, significant cloud types will be reported in the observation using the
following guidance. (T-1).

11.5.2.1. When observed and within 10nm, cloud layers with cumulonimbus (CB) or
towering cumulus (TCU) are identified by appending the contractions CB and/or TCU to
the layer height and are further described in column 13 remarks. Note: Only one
contraction is appended to each layer in the body of the observation; CB has priority if both
are observed at the same layer height.
11.5.2.2. When observed and beyond 10nm, CB and TCU are not appended to the cloud
layer report. In this case, only a column 13 remark is used (e.g., CB 14NW-20NNE MOV
SE AND TCU DSNT S).
11.5.2.3. All other significant cloud features are reported in column 13 as remarks
following guidance in Attachment 3.
11.5.3. To determine total layer coverage and total sky cover, from a location that affords the
maximum view of the celestial dome, mentally divide the sky into halves, quarters and/or
eighths and estimate the layer coverage amount starting with the lowest layer. Using the
summation principle, add each successive layer amount in eighths estimated. See Figure 11.1
for sky cover example.

11.5.3.1. When evaluating interconnected layers formed by the horizontal extension of
cumulus, a layer will only be treated as separate if the base appears horizontal and at a
different height than the parent cloud. Otherwise, the entire cloud is regarded as a single
layer and is annotated with the height of the base of the parent cloud (i.e. a well-developed
anvil from a CB may be treated as its own separate layer).

11.5.3.2. Determine total layer and sky cover amount based on what is actually seen, to
include the bases and sides of clouds or obscuring phenomenon. Do not reduce coverage
estimation to compensate for the packing effect that is commonly seen with cumuliform
clouds. The packing effect is observed as an increased sky coverage amount due to the
viewing angle of the sides of clouds when looking to the horizon. See Figure 11.2 for an
example of the packing effect.