Announcement

Collapse
No announcement yet.

How to read a Terminal Area Forecast (TAF)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • How to read a Terminal Area Forecast (TAF)

    In one of the other threads, it was requested that somebody make a post in here about how to read a TAF. So as requested, here it is. If you have any other questions, or if something doesn't make sense, just post and I'll try to explain it a little better.

    First off, I've found that the best aviation weather source is http://adds.aviationweather.gov That is where I reccomend you go if you are looking for a TAF. Just click on the TAF tab at the top and type in the airport code (works for airports all over the world if I remember correctly). Hit submit and you'll be all set.

    The best way to learn something in my opinion is through application. So what instead of just saying what each section and abreviation stands for, I'm going to post a real one from a place that is having interesting weather, and then we'll dissect

    First off, A TAF is a product put out by the national weather service to describe the expected weather conditions over a 24 hour period. The only downside is that it only covers a 5 mile radius around the airport. that's not exactly a big area, but unless you're having some strange weather, it should work pretty well for the surrounding area too, just not always. Another thing to point out is that not every airport has a TAF, its only selected airports, usually the larger/more frequently used ones in a given area. TAFS are issued 4 times a day at 0000 0600 1200 and 1800 Zulu (GMT).

    I have no idea where STS is, other than that its in California, but this is the TAF we're gonna look at.

    KSTS 110541Z 110606 VRB03KT P6SM SKC
    FM1200 00000KT 1/4SM FG VV001
    FM1700 VRB03KT 5SM BR SCT006
    FM1800 16007KT P6SM SKC
    FM0500 VRB03KT P6SM SKC

    Top Line-Gives you some general info about the TAF

    KSTS-Airport Identifier

    110541Z-Date and Time the forecast was issued. In this case it was issued on the 11th day of the month at 0541Z. All times in a TAF are Zulu (GMT)

    110606- This is the time which the forecast is valid. Again, the first number is the day of the month (the 11th) from 06Z until 06Z the following day. They leave out the date because its understood that with the forecast being valid for 24 hours, its probably going to expire on a different day than it was issued.

    VRB03KT P6SM SKC -The last part of the top line is the expected conditions for the forecast.

    Body-Obviously, in 24 hours the weather can change quite a bit from what is first forecast. The body of the TAF lists what the expected changes in weather are, as well as the estimated times that the change will occur.

    FM1200 00000KT 1/4SM FG VV001-So from 6Z on, you can expect the weather to be what it says in the upper line. But looking at the first line of the body, it says From 1200Z (FM1200) the wind will be calm. (00000KT ). Usually the first 3 numbers is the direction the wind is coming from, and the following two, the speed. But when the wind is calm, 00 is the default direction. Visibility will be 1/4th of a Statute mile (1/4SM ) in fog (FG). Vertical Visiblity, or how far you can see if you looked straight up, is 100ft (VV001). The number following VV is in hundreds of feet, so 010 would be 1,000 feet. You will only see VV included in the TAF when visibility is restricted by something such as fog.

    The rest of the TAF is set up just like the first line. There are a couple things things you may see different in other TAFs. It would take forever to cover them all in depth, so I'll try to give a quick overview of what they might be and feel free to ask if you have any specific questions about something I didn't cover.

    One of these things is different weather phenomenon (which I'll list a bunch of commonly used ones at the bottom of the post). In this TAF you see fog. Other things that might be in there are rain, snow, sleet, hail, mist, etc. There may be qualifiers in front of these. Such as +RA means heavy rain -RA means light rain, and if its just RA it is moderate.

    If you're wondering what P6SM means, its +6 miles. 6 miles is the most you'll see forecasted in a TAF. Visibility could be well more than 6 miles, but they feel that if it gets to 6, its good enough.

    Another thing you may see different is that instead of FM1200 at the beginning of a line, you'll see TEMPO 1214. That means whatever they are forecasting in that line is going to be temporary from 12z to 14z. After 14Z weather is expected to go back to whatever it was before the change.

    TAFs are fairly uniform throughout the world with a few minor differences. One of the more obvious ones is that visibility will be reported in meters. The max forecasted visibility then is usualy 9999 meters. US military bases also report their visibility in meters because their pilots are flying all over the world, so they feel its a help to keep their pilots from needing to do conversions.

    Some other countries will report winds in meters per second, though I believe most of them use Knots.

    That's about all I can think of for right now. I know its a lot of stuff at once, and it wasn't exactly organized the best, but definately let me know if you need me (or anyone else) to clarify anything, or if you find something I didn't cover.

    Here's a list of commonly used abreviations found in TAFs for weather phenomenon, (some of them make sense, some of them dont even come close):

    Precipitation
    DZ-Drizzle RA-Rain SN-Snow SG-Snow Grains IC-Ice pellets
    PL-Ice Pellets GR-Hail GS-Small Hail or Snow Pellets UP-Unknown Precip

    Obscuration
    BR-Mist FG-Fog DU-Dust HZ-Haze PY-Spray VA-Volcanic Ash FU-Smoke

    Other
    PO-Dust/Sand whirls SQ-Squalls FC-Funnel Cloud +FC Tornado/Waterspoout
    SS-Sandstorm DS-Dust Storm

  • #2
    Someone's practicing.....

    Excellent work!!
    Anybody can fly a round airplane....

    Comment


    • #3
      Originally posted by N9103M
      Someone's practicing.....

      Excellent work!!
      now I just need some completion standards and review questions

      Comment


      • #4
        Excellent explanation Joe .

        Comment


        • #5
          Fantastic, so let me see if i get this correct...

          KLAS 111202Z 111212 31011KT P6SM SCT060 BKN110
          TEMPO 1416 BKN060
          FM1600 22008KT P6SM SCT060 BKN110
          FM1900 VRB05KT P6SM SCT060
          FM0200 23006KT P6SM SKC

          Is the TAF...
          So on the 11th @ 1212z it was issued and is valid from 12z to 12z tomorrow. Winds 310 degrees at 11kts. 6 Miles Visibility. Scattered Clouds at 6000ft and Broken at 11,000ft then temporarily from 14z to 16z the clounds will be Broken at 6000ft.

          etc etc

          ?

          Comment


          • #6
            great explaination Joe! Thanks.
            Christian Vlček Sullivan | Through The Fence Photography
            Forever New Frontiers

            Comment


            • #7
              Outstanding.

              You're hired. (That means you'll never speak to me again.)
              Bite me Airways.....

              Comment


              • #8
                Great explanation Joe!
                sigpic
                http://www.jetphotos.net/showphotos.php?userid=170

                Comment


                • #9
                  Originally posted by Myriad
                  Fantastic, so let me see if i get this correct...

                  KLAS 111202Z 111212 31011KT P6SM SCT060 BKN110
                  TEMPO 1416 BKN060
                  FM1600 22008KT P6SM SCT060 BKN110
                  FM1900 VRB05KT P6SM SCT060
                  FM0200 23006KT P6SM SKC

                  Is the TAF...
                  So on the 11th @ 1212z it was issued and is valid from 12z to 12z tomorrow. Winds 310 degrees at 11kts. 6 Miles Visibility. Scattered Clouds at 6000ft and Broken at 11,000ft then temporarily from 14z to 16z the clounds will be Broken at 6000ft.

                  etc etc

                  ?

                  That is correct. Glad everybody seemed to understand it. Feel free to let me know if there are any other subjects you want me to cover. Preferably related to general aviation aircraft as that is what I have all my experience in.

                  Comment


                  • #10
                    I saw this the other day on a digital ATIS. Not a clue what it meant but it was FBL SH. Now, SH is showers, and BL I believe is blowing.....but FBL? The captain didn't have a clue and I have since asked a few crew none of which know. Frequent Blowing showers?
                    Have a look at my photos, including Kai Tak crazy landings!http://www.jetphotos.net/showphotos.php?userid=460

                    Comment


                    • #11
                      Here's a question for you guys. Who knows what the bold part in the line below means? I saw this in DAY's TAF last night. It's not on the current one anymore, so I copied a line from it & put the line next to it.

                      FM1800 23018G35KT P6SM BKN035 WS020 24045KT

                      I looked it up last night & know what it means, I wanted to see if anybody else could figure it out. I had never seen it until then.

                      Originally posted by screaming_emu
                      Here's a list of commonly used abreviations found in TAFs for weather phenomenon, (some of them make sense, some of them dont even come close):

                      Obscuration
                      BR-Mist
                      My instructor had no idea why they did BR for mist either, but he gave me a good way of remembering it. He told me to think of Mist as BR- "Baby Rain".

                      DeltaRules


                      http://www.flightlevel350.com/aviati...r=Josh+Sprague

                      Comment


                      • #12
                        Originally posted by DeltaRules
                        Here's a question for you guys. Who knows what the bold part in the line below means? I saw this in DAY's TAF last night. It's not on the current one anymore, so I copied a line from it & put the line next to it.

                        FM1800 23018G35KT P6SM BKN035 WS020 24045KT

                        I looked it up last night & know what it means, I wanted to see if anybody else could figure it out. I had never seen it until then.



                        My instructor had no idea why they did BR for mist either, but he gave me a good way of remembering it. He told me to think of Mist as BR- "Baby Rain".

                        DeltaRules
                        It means WINDSHEAR @ 2000FT from 240 degrees at 45 knots.
                        It's time to fly.
                        //// U N I T E D

                        Comment


                        • #13
                          BR comes from the French word for fog (or something like that). Broum, I think.

                          At least according to that Marth King wench.
                          Bite me Airways.....

                          Comment


                          • #14
                            Originally posted by LRJet Guy
                            BR comes from the French word for fog (or something like that). Broum, I think.

                            At least according to that Marth King wench.
                            The Kings might be the 2 most annoying people on earth

                            Comment


                            • #15
                              Two airports less than 10 miles from eachother...I'm supposed to fly at 1730Z...according to these TAFs the weather will be real nice...or its gonna have freezing rain.

                              KGFK 181138Z 181212 20012KT P6SM SCT140 BKN250
                              FM2000 22014G22KT P6SM OVC050
                              TEMPO 2101 -RA OVC030
                              FM0100 29013KT P6SM -RA OVC015
                              TEMPO 0105 5SM -RA BR OVC008
                              FM0500 33015KT P6SM OVC010


                              KRDR 181410 17010KT 9999 FEW100 BKN200 QNH2998INS
                              BECMG 1415 24010G15KT 8000 -RASN BKN030 BKN100 620307 QNH2972INS
                              TEMPO 1518 -FZRA BKN030 OVC050 690003 610302
                              BECMG 1920 24012G20KT 8000 -RA BKN020 OVC030 640209 QNH2953INS
                              BECMG 0001 32012G20KT 4800 -RASN BKN020 OVC030 640209 QNH2949INS
                              BECMG 0405 33015G25KT 9999 NSW BKN020 OVC030 620209 QNH2953INS T02/20Z TM04/09Z 1410


                              Right now the observations (METAR) are

                              KGFK 181553Z 20012KT 10SM FEW070 SCT100 OVC200 M01/M03 A2977 RMK AO2 SLP093 T10111028

                              KRDR 181555Z 20012KT 7SM FEW100 OVC200 M00/M03 A2975 RMK SLP089 WR//

                              And I can see some clouds out to the west that are definately lower than 7,000ft.

                              Comment

                              Working...
                              X