wishboneash Posted January 23, 2015 Report 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
mooniac15u Posted January 23, 2015 Report 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
wishboneash Posted January 23, 2015 Author Report 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
mooniac15u Posted January 23, 2015 Report Posted January 23, 2015 I think you are probably right. That's what I use to remember how to decode them. Quote
M20F Posted January 23, 2015 Report 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
mooniac15u Posted January 23, 2015 Report 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
ChrisH Posted January 24, 2015 Report Posted January 24, 2015 what? and here I thought BR=Baby Rain 1 Quote
Dave Marten Posted January 25, 2015 Report 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
Hank Posted January 25, 2015 Report 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
BorealOne Posted January 28, 2015 Report 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
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