When decoding a METAR, how does sea level pressure (SLP) work?

The METAR for my area states in the remarks section "SLP147=". I'm not sure whether to put a 10 in front or a 9. I also don't get what the equals sign is there for.

2 Answers

  • 2 weeks ago
    Best Answer

    Well, sea level pressure usually ranges from around 950.0mb to 1040.0mb (though the records are 870 and 1080.  So basically if the SLP value is above 500 (50.0) you put a 9 in front and if it is below 400 (40.0) you put a 10.

    = means the end.

  • 2 weeks ago

    If it's 947 you may wish to get your aircraft under cover.

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