AIM

8/15/19

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Meteorology

(j) Significant clouds.

When significant

clouds are observed, they are shown in remarks,
along with the specified information as shown below:

(1)

Cumulonimbus (CB), or Cumulonim-

bus Mammatus (CBMAM), distance (if known),
direction from the station, and direction of
movement, if known. If the clouds are beyond
10 miles from the airport, DSNT will indicate
distance.

EXAMPLE

−

CB W MOV E

“cumulonimbus west moving

. . . . . . .

east”

CBMAM DSNT S

“cumulonimbus mammatus 

. . . .

distant south”

(2)

Towering Cumulus (TCU), location, (if

known), or direction from the station.

EXAMPLE

−

TCU OHD

“towering cumulus overhead”

. . . . . . . . .

TCU W

“towering cumulus west”

. . . . . . . . . . . .

(3)

Altocumulus Castellanus (ACC), Stra-

tocumulus Standing Lenticular (SCSL),
Altocumulus Standing Lenticular (ACSL), Cirrocu-
mulus Standing Lenticular (CCSL) or rotor clouds,
describing the clouds (if needed) and the direction
from the station.

EXAMPLE

−

ACC W

“altocumulus castellanus  west”

. . . . . . . . . . . . .

ACSL SW

−

S

“standing lenticular 

. . . . . . . . .

altocumulus southwest
through south”

APRNT ROTOR CLD S “apparent rotor cloud south”
CCSL OVR MT E

“standing lenticular 

. . . . .

cirrocumulus over the 
mountains east”

10. Temperature/Dew Point.

Temperature

and dew point are reported in two, two-digit groups
in degrees Celsius, separated by a solidus (“/”).
Temperatures below zero are prefixed with an “M.”
If the temperature is available but the dew point is
missing, the temperature is shown followed by a
solidus. If the temperature is missing, the group is
omitted from the report.

EXAMPLE

−

15/08 

“temperature one five, 

. . . . . . . . . . . . . .

dew point 8”

00/M02 “temperature 

zero,

. . . . . . . . . . . .

dew point minus 2”

M05/

“temperature minus five, 

. . . . . . . . . . . . . . .

dew point missing”

11. Altimeter.

Altimeter settings are reported

in a four-digit format in inches of mercury prefixed
with an “A” to denote the units of pressure.

EXAMPLE

−

A2995 

−

 “Altimeter two niner niner five”

12. Remarks.

Remarks will be included in all

observations, when appropriate. The contraction
“RMK” denotes the start of the remarks section of a
METAR report.

Except for precipitation, phenomena located within
5 statute miles of the point of observation will be
reported as at the station. Phenomena between 5 and
10 statute miles will be reported in the vicinity, “VC.”
Precipitation not occurring at the point of observation
but within 10 statute miles is also reported as in the
vicinity, “VC.” Phenomena beyond 10 statute miles
will be shown as distant, “DSNT.” Distances are in
statute miles except for automated lightning remarks
which are in nautical miles. Movement of clouds or
weather will be indicated by the direction toward
which the phenomena is moving.

(a)

There are two categories of remarks:

(1)

Automated, manual, and plain lan-

guage.

(2)

Additive and automated maintenance

data.

(b) Automated, Manual, and Plain Lan-

guage.

This group of remarks may be generated

from either manual or automated weather reporting
stations and generally elaborate on parameters
reported in the body of the report. (Plain language
remarks are only provided by manual stations).

(1)

Volcanic eruptions.

(2)

Tornado, Funnel Cloud, Waterspout.

(3)

Station Type (AO1 or AO2).

(4)

PK WND.

(5)

WSHFT (FROPA).

(6)

TWR VIS or SFC VIS.

(7)

VRB VIS.

(8)

Sector VIS.

(9)

VIS 

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