Prepared by: Troy M. Kimmel, Jr.
                     Lecturer, Studies in Weather and Climate
                     Manager, Weather and Climate Resource Center
                     Department of Geography, University of Texas at Austin

                     Certificate Holder, National Weather Service Certificate of Authority to Take Weather Observations

A METAR is the Aviation Routine Weather Observation created at thousands of locations (primarily, airports) around the world every hour. It provides insight on a number of weather elements being observed at the airport or observing location. Each observing location is unique in what is reported... the largest airports report all types of automated and humanly augmented data... while smaller locations may be completely automated and don't include any humanly augmented information.

Here is an example of a METAR:

KAUS 092135Z 26018G25KT 8SM -TSRA BR SCT045CB BKN060 OVC080 30/21 A2992 RMK FQT LTGICCCCG OHD-W MOVG E  RAB25 TSB32 CB ALQDS  SLP132 P0035 T03020210 =

So what does this METAR tell us?

KAUS - Austin Bergstrom International Airport

092135Z - Date/Time Group. "09" is the day of month... "2135Z" is Greenwich time or 3:35 pm CT

26018G25KT - Wind Group. Direction is "260 degrees" (west wind)... at 18 gusting to 25 knots (multiply by
                           1.15 to get speed in miles per hour)

8SM - Visibility (8 statute miles)

-TSRA BR  - Current Weather type/Obscurations to Visibility... In this case, thunderstorm and light rain... mist
                       Some other commonly used abbreviations:
                       FG (Fog)                        GR (Hail)                            SN (Snow)
                       FZRA (Freezing Rain)     FZDZ (Freezing Drizzle)     RA (Rain)
                       TS (T'Storm, no rain)      PL (Ice Pellets)                   DZ (Drizzle)
                       VCTS (T'Storm in the Vicinity)

SCT045CB BKN060 OVC080 - Cloud bases/types ... cloud coverage is based on Octas (8ths of sky)
            There is a scattered layer of clouds, in fact, cumulonimbus clouds, that are covering 2/10-4/10ths of the sky
            with bases at 4,500 feet AGL. Other cloud bases are at 6,000 and 8,000 feet AGL that, when cumultatively
            added to underlying cloud layers, ccreate broken and then overcast layers.

30/21 - Air temperature/dewpoint temperature group in whole degrees Celsius
             In this case, air temperature is 30 degrees C... dewpoint temperature is 21 degrees C.

A2992 - Altimeter (pressure) reading in inches of mercury (29.92 in/hg)

RMK - Remarks section follows

              Thunderstorm/precipitation comments... there is frequent lightning (in cloud, cloud-to-cloud, and
              cloud-to-ground) overhead through the west... rain began at 25 minutes after the hour... the thunderstorm
              began at 32 minutes after the hour... there are cumulonimbus clouds visible in all quadrants of the sky

SLP132 - Sea Level Pressure Reading in millibars (to the tenths place)
                You add a "9" or "10" before this number to get the number closest to 1000 mb
                In this case.. the reading is equal to 1013.2 millibars

P0035 - Precipitation amount since the top of the last hour in hundredths of an inch
              In this case, 0.35" has fallen

T03020210 - Air Temperature/Dewpoint Temperature Group (to tenths of a degree)
                      A degree of celsius is larger (by a factor of 1.8) than a degree of fahrenhiet. As a result, we need to
                      have the air temperature/dewpoint temperatures to a tenth of degree (the temperatures earlier in the
                      report are rounded). The temperature, depicted by the first four numbers in this sequence
                      following the "T", is 30.2 degrees C, the dewpoint (depicted by the second group of 4 numbers)  is 21.0 C.

Adapted from paper originally prepared by Larry Riddle, Climate Research Division, Scripts Institute of Oceanography

Prepared by: Troy M. Kimmel, Jr.
                    Lecturer, Studies in Weather and Climate
                    Manager, Weather and Climate Resource Center
                    Department of Geography, University of Texas at Austin

                    Certificate Holder, National Weather Service Certificate of Authority to Take Weather Observations

When we examine surface weather observations, better known as METARS (roughly translates from the French as Aviation Routine Weather Report), it is important that you understand that they represent the weather conditions that existed at one particular time at one specific location (usually an airport). Observed conditions may or may not be regional in scope. For example, a thunderstorm and rain shower reported at Austin Bergstrom International Airport does not necessarily mean that there is a thunderstorm and rain shower over other areas of Austin. Rainfall measurements during that same thunderstorm and rain shower at Austin Bergstrom International Airport simply means how much rain fell in a six inch diameter area (the rain gauge diameter) at Austin Bergstrom International Airport.

Routine weather observations are usually transmitted just before the top of the hour with special weather observations transmitted as certain established meteorological criteria are met.


METARS can be as simple as...

KTVL 021553Z 02012KT 10SM SKC 15/05 A3000

...or as complex as...

KMWL 111155Z 13012KT 8SM -TSRA SCT100CB OVC250 08/06 A2998 RMK RAB32 OCNL LTGIC VC         SW-OHD TSB34 MOV NE P0012 T00780059 SLP150 10105 20052 60012

A METAR primarily consists of four parts, the last of which (a remarks section) isn't always in the observation. Using this last more complex observation, let's take a look at each of these elements.

PART 1: Identification
KMWL 111255Z

Observation taken at Mineral Wells, TX Airport

Observation taken on the 11th day of the month (first two digits) and at 1155 Universal Coordinated Time (time along the Greenwich Meridian); also called "Zulu" time.. thus the "Z."

How you do you tell local time?
In order to calculate local time for the observation, you must know how many time zones you are away from the Greenwich Meridian. Here in central Texas, we are in the Central Time zone, or six time zones away from the Greenwich Meridian. Accordingly, you should subtract 6 hours from the time on the METARS to get local time during standard time; you should subtract 5 hours from the posted time when we are observing daylight savings time. Assuming this observation was during December (during CST), we subtract 6 hours to get a local time in Mineral Wells of 5:55 a.m.

PART 2: Observation
13012KT 8SM -TSRA SCT100CB OVC250

Wind Speed and Direction
Add a zero to the first two numbers (13) to come up with 130. This tells us that the winds are blowing from 130 degrees from true north (130 degrees degrees clockwise from true north).
The last three numbers tells us wind speed in knots.. in this case 12 knots. If there had been wind gusts to 25 knots, the observation would have read "13012G25KT."
FYI.. In order to convert winds to mph, remember that 1 knot equals 1.15 mph.

Visibility in statute miles (SM). Any visibility less than seven (7) miles must have a weather type  following it to denote what is reducing the visibility.
The visibility may be followed by something like R28L/2000ft. This is what we call a "runway visual range" (runway visibility) observation. The RVR reading above says "runway 28L visibility is 2000 feet. M2000 says "less than 2000" (M stands for minus) and P2000 says "greater than 2000 feet" (P stands for plus).

Current weather (if there is any)
This stands for a thunderstorm (TS) and light (the - that preceeds the weather type) rain.

Here is a list of weather descriptors that you will see used in this current weather section...

Intensity:   -      Light Intensity
                       Moderate Intensity (no symbol)
                +     Heavy Intensity
                VC  In the Vicinity

Descriptor:   MI Shallow          PR Partial           BC Patches             DR Low Drifting
                    BL Blowing         SH Showers        TS Thunderstorm    FZ Freezing
                    VCTS Thunderstorm in the Vicinity

Precipitation:    RA Rain                    DZ Drizzle                    SN Snow                    SG Snow Grains
                        IC Ice Crystals          PL Ice Pellets (Sleet)    GR Hail                      GS Small Hail/Snow Grains
                        UP Unknown Precipitation

Obscuration:    FG Fog (less than 5/8 mi visibility)                BR Mist (fog with 5/8 to 7 mi visibility)
                       HZ Haze                                                      FU Smoke
                       DU Widespread Dust                                   SA Sand
                       PY Spray (sea)                                            VA Volcanic Ash

Others:    SQ Squall                                                  DS Duststorm                             SS Sandstorm
               PO Well Developed Dust/Sand Whirls       FC Funnel Cloud                         +FC Tornado

Cloud coverage and type as well as height of base.
The clouds over Mineral Wells are in two observable layers at the time of this observation. The first layer is a "scattered" layer with its bases at 10,000 feet AGL (you add two zeros to the numbers shown.. 100 becomes 10,000 feet) with the second layer being an "overcast" layer at 25,000 feet (250 becomes 25,000).
The "CB" that follows the first cloud group.. the one with bases at 10,000 feet AGL.. denotes that this is a cumulonimbus (thunderstorm) cloud.

Here is how we define the cloud coverage in METAR observations:

         SKC      No clouds (manual weather station)
         CLR       No clouds below 12,000 feet (automated ASOS/AWOS stations)
         FEW      Few Clouds (1/8 to 2/8 of the sky is covered with clouds)
         SCT       Scattered Clouds (3/8 to 4/8 of the sky is covered with clouds)
         BKN      Broken Clouds (5/8 to 7/8 of the sky is covered with clouds)
         OVC      Overcast Clouds (8/8 or all of the sky is covered with clouds)

Here is simple table of cloud types (code numbers are sometimes used in remarks section):

                    Low                              Middle                             High
   Code        Cloud Type                    Cloud Type                      Cloud Type

      0            No Clouds Present        No Clouds Present           No Clouds Present

      1            Cu (Fair Weather)         As (Thin,Sun vsbl)            Ci (Filaments,strands)
      2            Cu (Towering/TCU)      As (Thick,no Sun)            Ci (Dense)
      3            Cb (No Anvil vsbl)        Ac (Thin;semitransparent) Ci (often left over from Cb)

      4            Sc (from Cu)                 Ac (Patchy)                      Ci (Hooks/Filaments thickening)
      5            Sc (not from Cu)           Ac (Thickening)                Ci/Cs (low on horizon;<45deg)
      6            St (in sheet/layer)           Ac (from Cu,Cb)              Ci/Cs (high in sky>45deg)

      7           CuFr/StFr (Bad Wx)      Ac (Ac w/As,Ns)              Cs (covering entire sky)
      8           Cu and Cs                      Ac (w/turrets)                   Cs (not covering entire sky)
      9           Cb (w/Anvil)                   Ac (Chaotic)                    Cc alone and/or Ci and Cs

   Abbreviations used:      Ac - Altocumulus               As - Altostratus
                                       Cb - Cumulonimbus           Cc - Cirrocumulus
                                       Ci - Cirrus                         Cs - Cirrostratus
                                       Cu - Cumulus                    StFr - Stratus Fractus
                                       CuFr - Cumulus Fractus     Ns - Nimbostratus
                                       Sc - Stratocumulus            St - Stratus
                                       TCU - Towering Cumulus (Cumulus Congestus)
                                       Wx - Weather

PART 3: Instrument Readings
08/06 A2998

This is the air temperature in celsius (whole/rounded degrees)

This is the dew point temperature in celsius (whole/rounded degrees)

The altimeter setting (a measure of barometric pressure) is 29.98 inches of mercury (corrected to sea level)

PART 4: Remarks and Coded Section
RMK RAB32 OCNL LTGIC VC SW-OHD TSB34 MOV NE P0012 T00780059 SLP150 10105 20052 60012

This remarks section (denoted by the code RMK) varies weather observing station to weather observing station. Some stations report remarks data in great details, other don't. We will only address what we're seeing in the Mineral Wells observation. For a complete detailed listing of all possible remarks, see pages 25-29.

Rain began at 32 minutes after the hour; in this case, at 1132Z

Occasional lightning in cloud in the vicinity of the weather observing station southwest through overhead

The thunderstorm (audible thunder) began at 34 minutes after the hour; in this case, at 1134Z... and is moving northeastward

Precipitation since last hourly observation; in this case, 0.12 inch

Air and Dew Point Temperature Celsius (in tenths of degrees)
First series of four numbers is air temperature... 7.8 degrees Celsius
Second series of four numbers is dew point temperature... 5.9 degrees Celsius
Note that these numbers, after rounding, are found in the instrument readings section above.
If either air or dew point temperature are below 0 degrees C, then the first number in the
four number series will become "1" instead of  "0." For example, T10501105 indicates
an air temperature of -5.0 degrees Celsius and a dew point temperature of -10.5 degrees Celsius.

SLP150 Sea Level Pressure (another way to express atmospheric pressure)
In this case is 1015.0 millibars (The last numbers is to the right of the decimal point.. a indication of tenths). You always prefix the numbers shown following the "SLP" with a "9" or a "10".. using the number that brings the total number closest to 1000.
Example: SLP025 equals 1002.5 millibars, SLP997 equals 999.7 millibars

10105  Maximum temperature over the last 6 hours is 10.5 degrees Celsius

20052  Minimum temperature over the last 6 hours is 5.2 degrees Celsius

60012  Precipitation recorded in the previous 6 hour period is 0.12 inch

Manual/Augmented Comments

Revised December 1999
Original April 1998

Prepared by: Troy M. Kimmel, Jr.
                    Lecturer, Studies in Weather and Climate
                    Manager, Weather and Climate Resource Center
                    Department of Geography, University of Texas at Austin

                    Certificate Holder, National Weather Service Certificate of Authority to Take Weather Observations

Manual or augmented comments in METAR weather observations are found toward the end of the observation in the "RMK' section.

Within these observations, you will find a number of abbreviations that have very specific meanings.
For example, location descriptions are specific:

AP - Airport - At Airport location
VC - Vicinity - Within 5 to 10 miles of the station (usual point of observation).. but not at the station
DSNT - Distant - More than 10 miles away from the station (usual point of observation)
ALQDS - All Quadrants

Let's now look at the proper order of the comments in the "RMK" section, per the National Weather Service and Federal Aviation Administration guidelines:

After the "RMK" abbreviation:

- A01/A02 (if present) indicate, at least, a partially automated observation
  A01 - Automated weather equipment without a precipitation type descriminator
  A02 - Automated weather equipment with a precipitation type descriminator

- +FC (tornado), FC (funnel cloud) location, beginning and ending time
   TORNADO B34 VC STN NW MOV NE - Tornado began 34 minutes after the hour in the vicinity station northwest
                 moving northeast
   FUNNEL CLOUD B34E39 - Funnel cloud began at 34 minutes after the hour.. ended at 39 after the hour..

- PKWND (peak wind) data
   PK WND 33026/1429 - Peak wind from 330 degrees at 26 knots at 1429Z

- WSHFT (wind shift)/FROPA (frontal passage) time
    WSHFT34 - Wind shift at 34 minutes after the hour
    WSHFT FROPA34 - Wind shift with frontal passage at 34 minutes after the hour (manual stations only)

- TWR (tower)/SFC (surface) visibility
   TWR VIS 1 - Tower Visibility is one mile
   SFC VIS 2 ½ - Surface Visibility is one mile

- VIS (visibility) variability
   VIS1V3 - Visibility variable between one and three miles

- SECTOR VIS (sector visibility)
   VIS N 3  - Visibility north is three miles

- VISIBILITY AT SECOND SITE (Automated Stations Only)
    VIS 2 RY36  - Visibility is two miles at runway 36

- Precipitation not at station
    SHRA VC S-SW - Rain showers vicinity observing station south through southwest

- Lightning location and frequency
    OCNL LTGIC DSNT N - Occasional lightning in cloud distant north
    FRQ LTGCCCG VC W - Frequent lightning cloud to cloud and cloud to ground vicinity of the airport
                                              observing station to the west
    CONS LTGCWCA ALQDS - Continuous lightning cloud to water and cloud to air all quadrants
    CONS LTGCG AT AP  - Considerable lightning cloud to ground at airport

    Note:  Lightning frequency is defined by the following terms:
              OCNL - Occasional - Less than 1 flash per minute
              FRQ - Frequent - About 1 to 6 flashes per minute
              CONS - Continuous - More than 6 flashes per minute

   Note: Lightning types are defined as follows:
            CG - Cloud to Ground            IC - In cloud                   CC - Cloud to cloud
            CA - Cloud to Air                  CW - Cloud to Water

- Precipitation beginning and ending
    RAB05E30 - Rain began at 5 minutes after the hour and ended at 30 minutes after the hour
    SNB30 - Snow began at 30 minutes after the hour
    RAE45 - Rain ended at 45 minutes after the hour

- Thunderstorm beginning and ending; location
    TSB05E30B52 - Thunderstorm began at 05 minutes after the hour, ended at 30 minutes after the hour then
                                began again at 52 minutes after the hour
    TSB12 - Thunderstorm ended at 12 minutes after the hour
    TS OVD MOV N - Thunderstorm is overhead and moving northeastward
    TS VC NE MOV NE - Thunderstorm is in the vicinity northeast of the observing station and is moving northeastward

 - GR (hail) size - over 1/4" in diameter (if below, coded as GS - Snow Grains, Small Hail)
    GR 3/4 - Hail diameter 3/4 inch

- Virga presence/location
    VIRGA SW - Virga observed southwest

- Variable ceiling height
    CIG 005V010 - Ceiling variable between five hundred and one thousand feet

- Obscuration(s)
     FG FEW000 - Fog obscuring 1/8 to 2/8ths of the sky
     VA SCT000 - Volcanic ash obscuring 3/8 to 4/8ths of the sky
     FU BKN020 - Broken layer (5/8 to 7/8ths of sky obscured) of smoke aloft based at 2,000 feet AGL

- Variable sky condition
    SCT V BKN - Scattered variable broken sky cover
    BKN025 V OVC - The broken layer at 2,500 ft AGL is variable broken to overcast

- CB (cumulonimbus), TCU (towering cumulus), other clouds location
    TCU DSNT SE - Towering Cumulus (Cumulus Congestus) distant southeast
    CB DSNT N-NE - Cumulonimbus distant north through northeast
    ACC W - Altocumulus castellanus west
    CCSL OVR MTNS E - Standing lenticular cirrocumulus over mountains east of station

- CEILING AT SECOND SITE (Automated Stations Only)
    CIG 020 RY36 - Ceiling of 2,000 feet AGL at runway 36

- PRESFR (pressure falling rapidly), PRESRR (pressure rising rapidly)

- SLP (sea level pressure) in millibars - prefix the numbers shown with a "9" or "10" which ever
    brings the total number (the last number is a tenths figure) closest to 1000.
    Examples: SLP105 - 1010.5 millibars
                    SLP997 - 999.7 millibars
                    SLPNO - Sea level pressure not available or not reported at this location

- ACFT MSHP (aircraft mishap) - Not transmitted externally

- NOSPECI (no specials issued) - Only hourly observations issued from this station

- SNINCR (snow increase in depth)
    SNOINCR 1/4  -  Indicates 1 inch snow in last hour with 4 inches total snow on ground

- FIRST/LAST observation - when stations do not report 24 hours a day

- P0000 - Precipitation since last hourly observation
    P0000 - A trace of rain (less than 0.01 inch)
    P0034 - 0.34 inch of rain
    P0565 - 5.65 inches of rain

- 60000 - 3 or 6 hourly precipitation (00Z,06Z,12Z,18Z obs have 6 hourly obs/03Z,09Z,15Z,21Z obs have 3 hourly rainfall)
    60000 - A trace of rain (less than 0.01 inch)
    60059 - 0.59 inch of rain

- 70000 (12Z obs only) - 24 hour precipitation
    70000 - A trace of rain (less than 0.01 inch)
    70001 - 0.01 inch of rain
    71245 - 12.45 inches of rain

- 4/--- Snow depth on ground
    4/001 - One inch of snow on the ground
    4/025 - Twenty five inches of snow on the ground

- 933---   Water equivalent of snow
    933036 - Water equilavent of snow is 3.6 inches

- 8/LMH   Cloud types (low, middle, high clouds)
    (See supplemental text page 22 for code numbers used for high/middle/low clouds)
    8/6// - Lower level clouds are stratus in sheets/layers; the / in the mid and high level cloud positions tells us that the low
              clouds are overcast preventing the observer from identifying any mid and high level cloud types.
    8/004 - No clouds in low and middle levels; Cirrus hooks and filaments noted as high cloud type.
    8/100 - Fair weather cumulus clouds in low clouds, no clouds above

-9/LMH   Cloud cumulative coverage (low, middle, high clouds) - Military stations ONLY
     9/700 - Low clouds cover 7/8ths of the sky, no mid and high level clouds
     9/8// - Low clouds cover 8/8ths of the sky; an overcast (not able to determine mid/high clouds
     9/138 - Low clouds cover 1/8ths of the sky, when added to the middle clouds then 3/8ths of the sky is covered
                 and, finally, when added to the high clouds then 8/8ths of the sky is covered (an overcast).

- Txxxxxxxx   Air temperature/dew point temperature (in tenths degrees C)
    T02040015 - first four numbers following the "T" (0204) depicts air temperature in Celsius
                          in tenths of degrees (20.4 degrees C); the second four numbers (0015) depicts dew point temperature in
                          Celsius in tenths of degrees (1.5 degrees C). When the air or dew point temperature is a negative number,
                          the first digit of each series will be "1" instead of "0"; Example: T10241040 = air temperature is -2.4C,
                          dew point temp is -4.0C.

- 10000     6 hour maximum air temperature
    10326 is 32.6 degrees Celsius
    11005 is -0.5 degrees Celsius

- 20000     6 hour minimum air temperature
    20015 is 1.5 degrees Celsius
    21040 is -4.0 degrees Celsius

- 4xxxxxxxx   (06Z ob only) Previous calendar day 24 hour maximum/minimum air temperature
    401550035 - first four numbers following the "4" tell you the calendar day maximum air temperature in tenths of degrees
                        (15.5 degrees C) while the second group of four numbers give you the calendar day minimum temperature
                        in tenths of degrees (3.5 degrees C).
                        When the maximum/minimum temperature is a negative number, the first digit of each series will be "1"
                         instead of "0"; Example: 410241040 = maximum temperature is -2.4C, mimimum temperature is -4.0C.

- 50000     3 hourly pressure change (in millibars)
   After the "5", the first number is a tendency code where 0-3 depicts that the pressure is higher than it was 3 hours ago,
   0 and 4-5 depicts pressure is the same as it was 3 hours ago and 5-8 depicts pressure lower than it was three hours ago.
   The last three numbers tells us the amount of pressure change, in millibars, over the last 3 hours.
   Examples: 56012 - Pressure is lower than it was three hours ago; pressure change was 1.2 millibars.
                   51032 - Pressure is higher than three hours ago; pressure change is 3.2 millibars.

- RVRNO     Runway visual range data not available

- PWINO     Present weather data not available

- PNO          Precipitation rain gauge data not available

- FZRANO  Freezing rain sensor data not available

- TSNO       Thunderstorm data not available

04Jul00 tmk