Training Guide in Surface Weather Observations - Multiple Choices

phenomenon causing the obscuration, a space, then the layer amount and height. For example, the
Remark “HZ SCT000” indicates that haze at the surface is hiding 3/8 to 4/8 of the sky.
8.2.1.5 Significant Cloud Types
Certain types of clouds are of particular importance to pilots. You are expected to be able to recognize
them. The direction of movement is the direction toward which the clouds are moving.
1. Cumulonimbus (CB) with or without an anvil. These are large cumulus-type clouds with dark
bases and are threatening in appearance. Report CB followed by direction from station, and if
known, the movement of the cloud with each entry separated by a space. For example, a CB up
to 10 statute miles southeast of the station moving toward the north would be coded “CB VC SE
MOV N.” A CB more than 10 statute miles east of the station would be coded “CB DSNT E.”
2. Cumulonimbus Mamma (CBMAM). This is a dark cloud with rounded protuberances hanging
downward from its base. Report CBMAM followed by the direction from the station, and if
known, the direction of movement of the cloud; e.g., “CBMAM ALQDS MOV N.” Append CB
to the cloud layer in the body of the report.
3. Towering Cumulus (TCU). This cloud is similar to “fair weather cumulus” but has a distinctly
shaded, often dark base, and strong vertical development. Report TCU followed by the direction
from the station; e.g., “TCU NW” or, if a towering cumulus cloud is more than 10 statute miles
west of the station, you would code “TCU DSNT W.”
4. Altocumulus Castellanus (ACC). These clouds are similar to cumulus clouds but are at a higher
level and are usually smaller. Report ACC followed by the direction from the station. For
example, an altocumulus cloud 5 to 10 statute miles northeast of the station would be coded
“ACC VC NE.”
5. Standing Lenticular, stratocumulus (SCSL), altocumulus (ACSL), or cirrocumulus (CCSL).
These clouds usually form in patches in the shape of plates, saucers, lenses, etc. They typically
form on the lee side of mountains or ridges and are often observed at several levels. Report the
cloud type followed by the direction from the station; entries shall be separated by a space. For
example, stratocumulus standing lenticular clouds observed east through south of the station
would be coded “SCSL E-S,” and altocumulus standing lenticular clouds over the station would
be coded “ACSL OHD.”
6. Rotor Clouds. These clouds form on the lee side of mountains or ridges. Report ROTOR CLD
followed by the direction from the station. For example, an apparent rotor cloud 5 to 10 statute
miles northwest of the station would be coded “APRNT ROTOR CLD VC NW.”
8.2.2 Additive Data Remarks
8.2.2.1 3- and 6-Hourly Precipitation Amount
The amount of precipitation (water equivalent) accumulated in the past 3 hours is reported in the 3hourly
report, and the amount accumulated in the past 6 hours is reported in the 6-hourly report. The
amount of precipitation is coded in the group 6RRRR, using the tens, units, tenths, and hundredths of
inches. For example, 0.15 inches of precipitation would be coded 60015. If an indeterminable amount
of precipitation occurred during the observing period, 6//// is coded. A trace is coded 60000. If no
precipitation occurred during the observing period, the group is omitted.
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