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METARs and TAFs have been around since before the high-speed internet made data transmission instantaneous so they use a somewhat cryptic method for encoding weather data. However, once you learn how to decode them they aren’t many surprises. Occasionally you see something different. This post is my list of unusual reports. For help in decoding, I use the ASOS Guide for Pilots and the Alaska Flight Services Group SA – METAR page. Even though you can get the decoded information on-line, it’s still a good idea to learn the abbreviations because sometime the information isn’t translated. Also, XM weather is displayed on the Garmin GPS Map in coded form, so knowing the codes makes it easier to see what’s ahead.

KSBP 091256Z COR 26003KT 4SM BR OVC007 08/07 A2994 RMK AO2 CIG 005V009 SLP138 T00830072 TSNO $

This is the first time I saw the COR notation. COR indicates a correction to a previously disseminated report.. In the remarks that the ceiling (CIG) is 500′ with a vertical visibility of 900′ (005V009). Note the $ at the end of the METAR. The symbol $ will appear if the ASOS detects that a preventative maintenance check is needed.

KRIV 271355Z AUTO 00000KT 10SM CLR 16/10 A2998 RMK AO2 SLP148 T01580101
KRIV 271212 VRB06KT 9999 SKC QNH2989INS WND 30012KT AFT 20 T35/23Z T13/13Z

KNFG 262321 24012G18KT 9999 FEW005 FEW120 QNH2984INS
KVBG 271414 VRB06KT 0400 FG VV001 QNH2995INS

This is the METAR and TAF for March AFB and the TAF for Camp Pendleton. Military airfields are the only places I’ve seen QNH forecast. QNH is the pressure at mean sea level. If reported in inches—as above—it is the setting on your pressure altimeter that yields field elevation. The first two digits of 9999 are the visibility in kilometers. The notation 99 means greater than 6 miles. In the Vandenberg AFB example visibility is 0400—.4 km. I don’t know what the last two digits are. I also have no idea what the information in the KRIV TAF from AFT on is.

KLAX 271453Z 00000KT 1/4SM R25R/3500VP6000FT FG VV001 17/16 A2996 RMK AO2 SLP142 T01670161 51014

If you fly out of smaller airports, you probably don’t see runway visual range data. R25R/3500VP6000FT is decoded as: R—RVR, 25R—for runway 25 right, 3500V—3500 varying to, P6000—greater than 6000, FT—measured in FT (RVR can also be reported in statute miles).

KMNN 080015Z AUTO 02018KT 8SM UP OVC013 M04/M07 A2993 RMK AO2 P0000

This is an automated report and the sensor detects precipitation but doesn’t know what kind, hence UP—Unknown Precipitation. Since the temperature is minus 4 °C it could be snow or freezing rain.

KSBP 250356Z AUTO 32006KT 8SM FU CLR 12/09 A2995 RMK AO2 SLP142 T01220094 TSNO

The code FU was fairly common this summer when much of California was on fire. It means smoke.

FM0000 36027G47KT 2SM RA BR OVC008
FM2200 01030G48KT 1SM +RA BR OVC008

Nothing hard to decode about this TAF for Providence, RI. There is a storm on the way with winds from 360 at 27 kts gusting to 47 kts. The winds shifts slightly and gets worse later in the day.

This entry was posted on Saturday, September 27th, 2008 at 8:56 am and is filed under Weather. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.