- LOCATION IDENTIFIER:
- 3 or 4 alphanumeric characters (usually airport identifier).
- TYPE OF REPORT:
- 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.
- TIME OF REPORT:
- Coordinated Universal Time (UTC or Z) using 24-hr. clock.
- STATION TYPE:
- AO2 = Unattended
(no observer) ASOS.
- AO2A = Attended
(observer present) ASOS.
- SKY 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
- E = Estimated
X = Obscured sky
- The letter V is added immediately following
the height of a base to indicate a variable ceiling: see Remarks.
- Reported 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
- S = Frozen precipitation
other than hail (e.g., snow).
- + = Heavy. No sign
= Moderate. -- = Light.
- OBSTRUCTIONS TO VISION:
- Reported only when visibility is less than 7 statute
- F = Fog H
- VOLCANIC ASH (when
- SEA-LEVEL PRESSURE:
- Tenths of Hectopascals (millibars). Shown as last 3 digits
only without decimal point (e.g., 950 - 995.0).
- TEMPERATURE AND DEW POINT:
- Degrees Fahrenheit.
- WIND 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.
- ALTIMETER SETTING:
- Hundredths of inches of mercury. Shown as last 3 digits
only without decimal point (e.g., 005 = 30.05 inches).
- MISSING DATA: Reported
- DENSITY ALTITUDE:
Included on voice broadcast only when 1000 more feet above airport elevation.
- REMARKS: Can Include:
- 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
- STATUS REMARKS:
- PWINO = Present weather information
- ZRNO = Freezing rain information
- TNO - Thunderstorm information
- $ = Maintenance check indicator.
- DECODED REPORT: Hometown
Municipal Airport, record special observation at 1755 UTC. ASOS with observer.
Measured ceiling 1900 feet variable, overcast. Visibility 1 mile, light
rain, fog. Sea-level pressure 1012.5 hectopascals, temperature 36°F,
dew point 34°F, wind from 210° true at 16 knots gusting to 24 knots,
altimeter 29.90 inches. Runway 29L visual range 1000 variable to 5000 feet.
Ceiling 1600 variable to 2200 feet, tower visibility 2 miles, peak wind
200° true at 32 knots at 1732 UTC< pressure falling rapidly. Freezing
rain information not available, maintenance check indicator.
- NOTE: Refer to
ASOS Guide for Pilots and the Airman's Information Manual
for more information. Refer to the Airport/Facility Directory,
aeronautical charts, and related publications for broadcast, telephone
and location data. Check Notices to Airmen for ASOS system status.