3 or 4 alphanumeric characters (usually airport identifier).
SA = Scheduled record (hourly) observation.
SP = Special observation indicating a significant change
in one or more of the observed elements.
RS = SA that also qualifies as an SP.
USP = Urgent special observation to report tornado.
Coordinated Universal Time (UTC or Z)
using 24-hr clock.
AO2 = Unattended (no observer) ASOS.
AO2A = Attended (observer present) ASOS.
CONDITION AND CEILING BELOW 12,000' AGL:
Sky condition contractions are for each layer in ascending
order. Numbers preceding contractions are base height in
hundreds of feet above ground level (AGL).
CLR BLO 120 = Less than 0.1 sky cover below 12,000'
SCT = Scattered: 0.1 to 0.5 sky cover.
BKN = Broken: 0.6 to 0.9 sky cover.
OVC = Overcast: More than 0.9 sky cover.
A letter preceding the height of a base identifies a ceiling
layer and indicates how ceiling height was determined.
M = Measured W= Indefinite
E = Estimated X = Obscured sky
The letter V is added immediately following the height of a
base to indicate a variable ceiling: see Remarks.
in statute miles and fractions from 1/4 through 10+.
V = variable:see Remarks.
TORNADO (when augmented).
T = Thunder(when augmented): see Status Remarks.
R = Liquid precipitation that does not freeze (e.g., rain).
P- = Light precipitation in unknown form.
ZR = Liquid precipitation that freezes on impact
(e.g., freezing rain): see Status Remarks.
A = Hail (when augmented).
S = Frozen precipitation other than hail (e.g., snow).
+ = Heavy. No sign = Moderate. - = Light.
Reported only when visibility is less
than 7 statute miles.
F = Fog H = Haze
VOLCANIC ASH (when augmented).
Tenths of Hectopascals (millibars).
Shown as last 3 digits
only without decimal point (e.g., 950 = 995.0).
AND DEW POINT:
DIRECTION, SPEED AND CHARACTER:
Direction in tens of degrees from true north. Voice broadcast
in degrees from magnetic. Speed in knots.
0000 = calm. E = estimated. G = gusts. Q = squalls.
Variable wind, peak wind, wind shift: see Remarks.
Hundredths of inches of mercury. Shown as last 3 digits
only without decimal point (e.g., 005 = 30.05 inches).
DATA: Reported as M.
ALTITUDE: Included on voice broadcast only when 1000
or more feet above airport elevation.
RVR (Runway Visual Range), VOLCANIC ASH, VIRGA,
TWR VSBY (Tower visibility), SFC VSBY (Surface visibility),
VSBY V (Variable visibility), CIG V (Variable ceiling),
WSHFT (Windshift), PK WND (Peak wind), WND V (Variable
wind direction), PCPN (Precipitation amount),
PRESRR (Pressure rising rapidly), PRESFR (Pressure falling
rapidly), PRJMP (Pressure jump), B (Time weather began),
E (Time weather ended).
PWINO = Present weather information not available.
ZRNO = Freezing rain information not available.
TNO = Thunderstorm information not available.
$ = Maintenance check indicator.