wishboneash Posted January 23, 2015 Report Share Posted January 23, 2015 This is new to me KMOD 231718Z 14004KT M1/4SM FG VV001 05/04 A3039 RMK AO2 T00500044 Is the M in front of 1/4SM indicate "measured" visibility? I have seen other METARs without the M in front. Thanks. Quote Link to comment Share on other sites More sharing options...
mooniac15u Posted January 23, 2015 Report Share Posted January 23, 2015 The "M" is used to indicate "less than" so M1/4SM is less than 1/4 statute miles visibility. It is the opposite of a "P" prefix for "greater than" as in P6SM. Quote Link to comment Share on other sites More sharing options...
wishboneash Posted January 23, 2015 Author Report Share Posted January 23, 2015 The "M" is used to indicate "less than" so M1/4SM is less than 1/4 statute miles visibility. It is the opposite of a "P" prefix for "greater than" as in P6SM. Thanks. I wonder where they came up with P and M (plus & minus, perhaps?). Quote Link to comment Share on other sites More sharing options...
mooniac15u Posted January 23, 2015 Report Share Posted January 23, 2015 I think you are probably right. That's what I use to remember how to decode them. Quote Link to comment Share on other sites More sharing options...
M20F Posted January 23, 2015 Report Share Posted January 23, 2015 METARS are derived from French is my understanding (which is why BR is mist) so would think the P/M tie to some French word other than plus/minus. Just a guess though. Quote Link to comment Share on other sites More sharing options...
mooniac15u Posted January 23, 2015 Report Share Posted January 23, 2015 Only a few of them are from French. Most are from the English words. Codes like RA=Rain and TS=Thunderstorm don't make sense from the French "pluie" and "orage." Quote Link to comment Share on other sites More sharing options...
ChrisH Posted January 24, 2015 Report Share Posted January 24, 2015 what? and here I thought BR=Baby Rain 1 Quote Link to comment Share on other sites More sharing options...
Dave Marten Posted January 25, 2015 Report Share Posted January 25, 2015 METARS are derived from French is my understanding (which is why BR is mist) so would think the P/M tie to some French word other than plus/minus. Just a guess though. The only +/- in the METAR/TAF code are used as qualifiers for intensity (+RA / -RA). For visibility M = Minus (less than) P = Plus (more than) As for the French, yes the French word for mist is brume. http://dictionary.reverso.net/english-french/mist. Hence mist = BR. Although I too prefer BR=Baby Rain http://www.aviationweather.gov/static/help/taf-decode.php Quote Link to comment Share on other sites More sharing options...
Hank Posted January 25, 2015 Report Share Posted January 25, 2015 I've gotten lazy using the NOAA Aviation Weather App, which offers "translated" and "raw" METARs. Guess someone wisely decided not to use "MI" or "MT" for mist, and needed something else. Thankfully fog is still "FG," although "line up and wait" makes me think of joining the conga line to taxi and not pulling onto the runway. Quote Link to comment Share on other sites More sharing options...
BorealOne Posted January 28, 2015 Report Share Posted January 28, 2015 This is new to me KMOD 231718Z 14004KT M1/4SM FG VV001 05/04 A3039 RMK AO2 T00500044 . Pretty sure that means "Hope you have an alternate" Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
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