Exclusive Tutorial
How to Decode METARs and TAFs Like a Pro
Chris Palmer Angle of Attack Aviator90
As I’m sure you already know, having the current weather observations and near
future forecasts for any flight you do is important. For aircraft like airliners (MD11,
747, 767) that have the capability to handle most situations, this is pretty easy. But
for aircraft that are single engine and lightly equipped for instrument conditions, this
could be disastrous. With that said, METAR and TAFs are important for ALL pilots and
ALL aircraft.
Let’s break this up into the different types. Although METARs and TAFs read much
the same, they show different things altogether. The main difference being a METAR
is the current observation, and a TAF is a forecast, or in other words, predicted
weather in the near future.
METARs mentioned a METAR is a current observation. This is automatically generated
by an on field reporting system which communicates with different outlets to give the
pilots information, whether it be for planning purposes or if the pilots are on
approach to land at the airport.
Keep in mind you won’t learn everything now, but you’ll have a good idea of what’s
going on. Later we’ll share sources with you that can be a resource for you into you
have a great grasp on METARs and TAFs.
Here is a simple METAR we will break down.
KSLC 192353Z 30004KT 10SM CLR 29/02 A3000 RMK AO2 SLP110
T02940017 10306 20261 56014
Location
KSLC is simply the airport of the observation, in ICAO (Pronounced I-K-OH in one
word) format.
Date and Time
192353Z is broken down into 2 sections. The first 2 numbers are the date of the
month. The next 5 digits are the four digit time and Z for Zulu. So, this METAR was
given on the 19th day of the Month at 2353Z.
Wind
30004KT is also broken into two parts. The first three digits are the wind direction,
and last two numbers is the windspeed in knots, noted by KT.
Visibility
10SM is the current visibility for the airport. This gets a bit for complicated when we
get in instrument conditions. Generally, 10SM means it is completely clear and
visible. This may also be noted as P6SM which stands for 6 statute miles and plus
(beyond)
Clouds
CLR means the area is clear of clouds. As you can see, CLR is very easily translated
into what it needs to be. As a simmer or even a pilot, most abbreviations can be
worked out very easily with just a little thought. With that said, other METAR
abbreviations make no sense. For example, mist in the area is noted in a METAR by
BR. Tell me how that makes sense.
Temperature and Dewpoint
29/02 is first temperature in Celsius, followed by the dewpoint. A small Temperature
and Dewpoint spread usually means that there will be more clouds in the area and/or
less visibility.
Barometric Pressure/Altimeter Setting
A3000 is the altimeter setting to be used by the pilot. This is the current pressure for
the airport. In addition, for those areas of the world that use Millibars, this will show
more like Q1011 rather than A3000.
RMK stands for Remarks.
Station Type
AO2 is a particular type of weather reporting station that can ‘discriminate’ if there is
precipitation or not. You won’t always see this in a METAR.
Sea Level Pressure
For those of you in the countries using millibars, SLP110 is the setting you’ll use, as
we discussed before.
Precise Temperature and Dewpoint
T02940017 notes our exact temperature and dewpoint. In this case, 29.4 and 1.7
degrees Celsius, respectively.
The last three sections are either jibberish or very advanced for this particular
METAR. As a pilot you’ll eventually learn what is important for your observation and
what isn’t. By using the resources we provide at the end of this tutorial, you’ll be
able to find answers to most of your questions.
Now for a more complex METAR
EIDW 092507Z 24035G55KT 210V270 1700 +SHRA BKN007 OVC015CB
08/07
The first two sections need not be explained again.
Winds
24035G55KT The winds are now much more interesting. The first part remains
unchanged, and in this case we are looking at winds from 240 at 35 knots. The
addon means that there are Gusts of 55 knots in the mix, although these are not
sustained winds.
The next chunk, 210V270, is also winds. This means that the winds are variable
between 210 and 270 heading. 240, from the first chunk of winds, is the average.
Visibility/RVR
In this case, 1700 is shown for visibility. This is not 1700 statute miles. Rather, it’s
1700 Meters. This means the visibility is quite low.
In this case, you can see it’s around 1 SM visibility. (1700= somewhere just above
1600, which is just under a mile above)
Precipitation
Omitted if not used, but in this case we see +SHRA. This means, SH, showers, RA,
rain, and plus, is heavy. So, we are looking at moderate rain showers.
Clouds
BKN007 notes a significant cloud layer. Simply add two 0’s onto this to get the
altitude of the cloud layer. In this case, we have broken clouds, which can be just
under overcast, at 700 feet.
OVC015CB notes that we have overcast (near complete or complete coverage) at
1500 feet. These clouds are CB, slang as Charlie Bravo, which is Cumulonimbus
clouds. Why is this important to know? Cumuloform clouds are most commonly
known with thunderstorms. No one and no aircraft messes with a thunderstorm and
feels good about it!
Temperature/Dewpoint
As mentioned before, a small spread between these two values will generally mean
poor visibility. In this case, it is a perfect example.
This does it for what we will teach you about METARs. Here are some great resources
to go out and study on your own:
Click HERE
TAFs
TAF stands for Terminal Aerodrome Forecast. What does Aerodrome mean?! In this
case, it doesn’t much matter. What you do need to know is that depending on
location, these will be anywhere between 9 and 24 hour forecasts.
TAFs look much the same as METARs, so most of it won’t need to be covered. But,
here are a few differences:
KORD 192335Z 2000/2106 14012G18KT 6SM -SHRA SCT015
BKN035 FM200100 17012G20KT P6SM BKN035 BKN060 TEMPO
2003/2004 5SM -TSRA BKN018CB FM200400 20012G20KT P6SM SCT020
SCT050 SCT120
Location
As usual, the ICAO code is given. In this case, KORD.
Time
This report was generated at 192335Z. Translated, it was reported on the 19th day
of the month at 2335Z.
Effective Dates/Times
This TAF is effective 2000/2106. This means 20th day of the month at 0000z (2000)
between (/) 21st day of the month at 0600z (2106)
On the rest of the first line, we get the start of the forecast. In this case, 0000z on
the 20th day of the month.
FM200100 means basically from this time forward ( 20th day of the month, 0100z)
this is what the weather will be (until changed on another line).
TEMPO 2003/2004 is a small slot of time where the forecast (on the remaining part
of the line) will be valid. In this case, on the 20th day at 0300z to 20th day 0400z.
The rest of the data shown are things that are common between METARs and TAFs.
Look the data up for questions as you are planning and using this data, so you’ll get
use to it.
Additional information can be found HERE
That does it for our simple explanation and introduction to TAFs and METARs!
Throttle On!
Chris Palmer