This is a coded observation of the current weather, which is mainly used for aviation. Each section has a definite format.
Example: YMML is Melbourne, Australia.
Example 302200Z 22:00Z on the 30th of the month.
ddd - the wind direction. 90 degrees is encoded 090.
kk - the wind speed in knots.
Gkk - if the wind is gusting, the gust speed in knots is added. (as in theis example).
dddVddd - If the wind direction is variable and the wind speed is greater than 6 knots, give the direction range. e.g. 23013KT 210V250
VRBkk - If the wind speed is variable and less than 6 knots, use VRB05KT.
Example: 36023G33KT 360 degrees heading, 23 kts speed with gusts to 33 kts.
vvvvv - visibility in statute miles. Visibility in fractional miles is encoded with a space, i.e. 2 1/4SM. Automated systems with visibilities less then 1/4 of a mile is encoded M1/4SM.
9999 - Visibility greater than maximum recorded value (e.g. 30 miles) is written as 9999
|- Light||MI Shallow||DZ Drizzle||BR Mist||PO Well developed dust / sand whirls|
|Moderate||PR Partial||RA Rain||FG Fog||SQ Squalls|
|+ Heavy||BC Patches||SN Snow||FU Smoke||FC Funnel clouds inc tornadoes or waterspouts|
|VC Vicinity||DR Low drifting||SG Snow grains||VA Volcanic ash||SS Sandstorm|
|BL Blowing||IC Ice crystals||DU Widespread dust||DS Duststorm|
|SH Showers||PL Ice pellets||SA Sand|
|TS Thunderstorm||GR Hail||HZ Haze|
|FZ Freezing||GS Small hail||PY Spray|
e.g. -SHRA - Light showers of rain
TSRA - Thunderstorms and rain.
nnn - Sky condition.
|BKN||(5/8, 6/8, 7/8)|
|VV||(8/8) - vertical visibility.|
hhh - cloud height in flight level (100 feet units)
FEW018 Few clouds at 1800 ft,
SCT030 Scattered clouds at 3000 ft,
BKN120 Broken clouds at 12,000 ft.
tt - Temperature in degrees celcius.
dd - Dewpoint in degrees celcius.
M - indicates a negative temperature or dewpoint.
Example 22/17 Temperature 22 degrees C, dewpoint 17 degrees C.
Qpppp - Pressure in hPa (or mb)
Ahhhh - Pressure in inches of Hg multiplied by 100 (29.95 inHg is encoded as A2995).
Example Q1001 is an atmospheric pressure of 1001 hPa, 1001 millibars, which is equivalent to 29.56 inHg.
Includes: Name of the volcano, Lat and Long or the direction and distance, date and time of the erruption, size, description of an ash cloud.
|Type -||Type of funnel clound. Can be one of|
B(hh)mm - Begining time (can also specify E(hh)mm for ending time). hh is the hour of the sighting, which is removed if redundant. mm is the minute of the sighting.
LOC - Location or direction of movement.
Example, TORNADO B24 3 SW indicates a tornado sighted at 24 minutes past the hour, 3 miles SW of the station.
AO1 - station without a precipitation descriminator.
AO2 - station with a precipitation descriminator.
ddd - wind direction
ff(f) - wind speed in kts
(hh)mm - time at which wind speed occurred.
Example: PK WND 32024/45 means a peak wind of 24 kts at 320 degrees occurred at 45 mins past the hour.
(hh)mm - The time the wind shift occurred.
FROPA - If the wind shift was the result of a frontal passage.
|Format:||TWR VIS vvvvv|
|SFC VIS vvvvv|
|VIS [DIR] vvvvv|
|VIS vvvvv [LOC]|
TWR VIS - Tower visibility
SFC VIS - Surface visibility
VIS [DIR] - Sector visibility with additional direction (e.g. VIS NE 2 - 2 miles visibility in the NE).
VIS vvvvv [LOC] - Visibility at a second location.
vvvvv - Visibility in statute miles.
VIS lllllVuuuuu - Variable visibility.
Frequency can be one of:
| ||OCNL||Occasional, less than 1 flash per min|
|FRQ||Frequent, 1 to 6 flashes per min|
|CONS||Continuous, more than 6 flashes per min|
LTG(type) can by one of:
[LOC] - location, can be either a station, or VC, DSNT for vicinity or distant.
Example, FRQ LTGICCC VC, which indicates frequent in-clound and cloud-cloud ligntning in the vicinity.
ww - weather phenomonon (eg RA).
(hh)mm - begining or ending time.
LOC - location
DIR - direction
Example, TS NW MOV NE Thunderstorms from the NW are moving to the NE.
size - size of the hailstones in inches.
DIR - direction.
hhh - Ceiling height in feet.
ww - weather phenomenon
[nnn] - amount of obscuration, if applicable (e.g. FEW, SCT, OVC)
hhh - height of obscuration.
Examples, FG FEW000, would be fog covering up to 2/8 of the sky at ground level.
nnn amount of obscuration (FEW, OVC etc)
hhh height of obscuration if applicable.
Type - one of,
|CLD||Standing lenticular or rotor clouds|
dir - Direction of cloud (N, NW, etc.)
mov - Movement of cloud if appropriate.
hhh - Height of ceiling in flight level units (100 feet).
[LOC] - Location of ceiling if appropriate.
ppp - pressure in hPa. If no pressure measurement is available, then NO is recorded.
iiiii - Increase in snow level in inches per hour.
ggggg - Snow level on the ground in inches.
YMML 302100Z 36027G37KT 9999 VCSH FEW045 SCT050 BKN120 21/17 Q1001
RERA INTER 2100/2400 3000 TSRA BKN010 FEW040CB FM2100 MOD/SEV TURB BLW 5000FT
YMML 302200Z 36023G33KT 9999 FEW018 SCT030 BKN120 22/17 Q1001
RMK RF00.0/000.4 INTER 2200/0100 3000 TSRA BKN010 FEW040CB
FM2200 MOD/SEV TURB BLW 5000FT
YMML 302300Z 01016KT 9999 -SHRA FEWSCT025 BKN035 20/18 Q1001
RERA RMK RF00.0/000.0 INTER 2300/0200 6000 SHRA BKN012
FM2300 MOD/SEV TURB BLW 5000FT
YMML 310000Z 02018KT 9999 -RA FEW018 SCT025 OVC140 20/19 Q0999
RERA RMK RF00.2/000.6 INTER 0000/0300 6000 SHRA BKN012
FM0000 MOD/SEV TURB BLW 5000FT
YMML 310100Z 36017KT 9999 VCSH FEW016 BKN025 OVC140 22/20 Q0999
RERA RMK RF00.0/000.8 INTER 0100/0400 6000 SHRA BKN012 FM0100 MOD/SEV TURB BLW 5000FT
YMML 310126Z 36021G34KT 9999 VCSH BKN025 23/19 Q0999
INTER 0126/0426 6000 SHRA BKN012 FM0126 MOD/SEV TURB BLW 5000FT
YMML 310153Z 36027G37KT 9999 -SHRA FEW018 BKN025 BKN035 23/18 Q0999
RERA INTER 0153/0453 6000 SHRA BKN012 FM0153 MOD/SEV TURB BLW 5000FT
YMML 310214Z 35022G33KT 4000 SHRA FEW016 BKN025 BKN035 20/17 Q1000
RERA FM0214 35025G40KT 9999 SHRA SCT015 BKN030 INTER 0214/0514
6000 SHRA BKN012 FM0214 MOD/SEV TURB BLW 5000FT
Last Updated: 17 February 2003. Richard Ogley