Enter a ZIP code to get a forecast:
Setup Location

WRN Logo

SYNOP Data Format (FM-12)

Surface Synoptic Observations

Table of Contents


Syntax

IIiii or IIIII YYGGi 99LLL QLLLL
iihVV Nddff 00fff 1sTTT 2sTTT 3PPPP 4PPPP 5appp 6RRRt 7wwWW 8NCCC 9GGgg
222Dv 0sTTT 1PPHH 2PPHH 3dddd 4PPHH 5PPHH 6IEER 70HHH 8aTTT
333 0.... 1sTTT 2sTTT 3Ejjj 4Esss 5jjjj jjjjj 6RRRt 7RRRR 8Nchh 9SSss


000 Group - Identification and Location

  • IIiii The WMO number of the station.
    Ship or Buoy Observations:
  • IIIII The ship or buoy identifier
  • YYGGi
    YY -- The day of the month
    GG  -- The hour of the observation (UTC)
    iw -- Wind type indicator
    0 -- m/s (estimated)
    1 -- m/s (from anemometer)
    2 -- knots (estimated)
    3 -- knots (from anemometer)
  • 99LLL QLLLL
    LLL -- Latitude of observation to .1 degrees
    Q -- Quadrant of observation
    1 -- North east
    3 -- South east
    5 -- South west
    7 -- North west

    LLLL -- Longitude of  observation to .1 degrees


111 Group - Land Observations

  • iihVV
    iR -- Precipitation indicator
    0 -- Precipitation in groups 1 and 3
    1 -- Precipitation reported in group 1 only
    2 -- Precipitation reported in group 3 only
    3 -- Precipitation omitted, no precipitation
    4 -- Precipitation omitted, no observation

    ix -- Station type and present and past weather indicator

    1 -- manned station -- weather group included
    2 -- manned station -- omitted, no significant weather
    3 -- manned station -- omitted, no weather observation
    4 -- automated station -- weather group included (see automated weather codes 4677 and 4561)
    5 -- automated station -- omitted, no significant weather
    6 -- automated station -- omitted, no weather observation
    7 -- automated station -- weather group included (see automated weather codes 4680 and 4531)

    h -- Cloud base of lowest cloud seen (meters above ground)

    0 -- 0 to 50 m
    1 -- 50 to 100 m
    2 -- 100 to 200 m
    3 -- 200 to 300 m
    4 -- 300 to 600 m
    5 -- 600 to 1000 m
    6 -- 1000 to 1500 m
    7 -- 1500 to 2000 m
    8 -- 2000 to 2500 m
    9 -- above 2500 m
    / -- unknown

    VV -- Visibility

    00 -- less than 0.1 km
    01 -- 0.1 km
    02 -- 0.2 km
    ...
    50 -- 5.0 km
    56 -- 6 km
    57 -- 7 km
    ...
    80 -- 30 km
    81 -- 35 km
    82 -- 40 km
    83 -- 45 km
    84 -- 50 km
    85 -- 55 km
    86 -- 60 km
    87 -- 65 km
    88 -- 70 km
    89 -- greater than 70 km
    90 -- less than 0.05 km
    91 -- 0.05 km
    92 -- 0.2 km
    93 -- 0.5 km
    94 -- 1 km
    95 -- 2 km
    96 -- 4 km
    97 -- 10 km
    98 -- 20 km
    99 -- greater than 50 km
    // -- missing
  • Nddff
    N -- Total cloud cover
    0 -- 0 eighths (clear)
    1 -- 1/8th
    2 -- 2/8ths
    3 -- 3/8ths
    4 -- 4/8ths
    5 -- 5/8ths
    6 -- 6/8ths
    7 -- 7/8ths
    8 -- 8/8ths (overcast)
    9 -- sky obscured
    / -- no observation

    dd -- wind direction in 10s of degrees
    ff -- wind speed in units determined by wind type indicator (see above)

  • 00fff (optional)
    fff -- wind speed if value greater than 100
  • 1sTTT -- Temperature
    s -- sign of temperature (0=positive, 1=negative)
    TTT -- Temperature in .1 C
  • 2sTTT -- Dewpoint
    s -- sign of temperature (0=positive, 1=negative, 9 = RH)
    TTT -- Dewpoint temperature in .1 C (if sign is 9, TTT is relative humidity)
  • 3PPPP -- Station pressure in 0.1 mb (thousandths digit omitted, last digit can be slash, then pressure in full mb)
  • 4PPPP -- Sea level pressure in 0.1 mb (thousandths digit omitted, last digit can be slash, then pressure in full mb)
    4ahhh -- Geopotential of nearest mandatory pressure level (use for high altitude stations where sea level pressure reduction is not accurate)
    a3 -- mandatory pressure level
    1 -- 1000 mb
    2 -- 925 mb
    5 -- 500 mb
    7 -- 700 mb
    8 -- 850 mb

    hhh -- geopotential height omitting thousandths digit

  • 5appp -- Pressure tendency over 3 hours
    a -- characteristics of pressure tendency
    0 -- Increasing, then decreasing -- resultant pressure same or higher
    1 -- Increasing, then steady -- resultant pressure higher
    2 -- Increasing steadily -- resultant pressure higher
    3 -- Decreasing or steady, then increasing -- resultant pressure higher
    4 -- Steady -- resultant pressure same
    5 -- Decreasing, then increasing -- resultant pressure lower
    6 -- Decreasing, then steady -- resultant pressure lower
    7 -- Decreasing steadily -- resultant pressure lower
    8 -- Increasing or steady, then decreasing -- resultant pressure lower

    ppp -- 3 hour pressure change in 0.1 mb

  • 6RRRt -- Liquid precipitation
    RRR -- Precipitation amount in mm
    001 -- 1 mm
    002 -- 2 mm
    ...
    988 -- 988 mm
    989 -- 989 or more mm
    990 -- Trace
    991 -- 0.1 mm
    992 -- 0.2 mm
    ...
    999 -- 0.9 mm

    t -- Duration over which precipitation amount measured

    1 -- 6 hours
    2 -- 12 hours
    3 -- 18 hours
    4 -- 24 hours
    5 -- 1 hour
    6 -- 2 hours
    7 -- 3 hours
    8 -- 9 hours
    9 -- 15 hours
    / -- 24 hours
  • 7wwWW -- Present and past weather
    ww -- Present weather
    00 -- clear skies
    01 -- clouds dissolving
    02 -- state of sky unchanged
    03 -- clouds developing
    Haze, smoke, dust or sand
    04 -- visibility reduced by smoke
    05 -- haze
    06 -- widespread dust in suspension not raised by wind
    07 -- dust or sand raised by wind
    08 -- well developed dust or sand whirls
    09 -- dust or sand storm within sight but not at station
    Non-precipitation events
    10 -- mist
    11 -- patches of shallow fog
    12 -- continuous shallow fog
    13 -- lightning visible, no thunder heard
    14 -- precipitation within sight but not hitting ground
    15 -- distant precipitation but not falling at station
    16 -- nearby precipitation but not falling at station
    17 -- thunderstorm but no precipitation falling at station
    18 -- squalls within sight but no precipitation falling at station
    19 -- funnel clouds within sight
    Precipitation within past hour but not at observation time
    20 -- drizzle
    21 -- rain
    22 -- snow
    23 -- rain and snow
    24 -- freezing rain
    25 -- rain showers
    26 -- snow showers
    27 -- hail showers
    28 -- fog
    29 -- thunderstorms
    Duststorm, sandstorm, drifting or blowing snow
    30 -- slight to moderate duststorm, decreasing in intensity
    31 -- slight to moderate duststorm, no change
    32 -- slight to moderate duststorm, increasing in intensity
    33 -- severe duststorm, decreasing in intensity
    34 -- severe duststorm, no change
    35 -- severe duststorm, increasing in intensity
    36 -- slight to moderate drifting snow, below eye level
    37 -- heavy drifting snow, below eye level
    38 -- slight to moderate drifting snow, above eye level
    39 -- heavy drifting snow, above eye level
    Fog or ice fog
    40 -- Fog at a distance
    41 -- patches of fog
    42 -- fog, sky visible, thinning
    43 -- fog, sky not visible, thinning
    44 -- fog, sky visible, no change
    45 -- fog, sky not visible, no change
    46 -- fog, sky visible, becoming thicker
    47 -- fog, sky not visible, becoming thicker
    48 -- fog, depositing rime, sky visible
    49 -- fog, depositing rime, sky not visible
    Drizzle
    50 -- intermittent light drizzle
    51 -- continuous light drizzle
    52 -- intermittent moderate drizzle
    53 -- continuous moderate drizzle
    54 -- intermittent heavy drizzle
    55 -- continuous heavy drizzle
    56 -- light freezing drizzle
    57 -- moderate to heavy freezing drizzle
    58 -- light drizzle and rain
    59 -- moderate to heavy drizzle and rain
    Rain
    60 -- intermittent light rain
    61 -- continuous light rain
    62 -- intermittent moderate rain
    63 -- continuous moderate rain
    64 -- intermittent heavy rain
    65 -- continuous heavy rain
    66 -- light freezing rain
    67 -- moderate to heavy freezing rain
    68 -- light rain and snow
    69 -- moderate to heavy rain and snow
    Snow
    70 -- intermittent light snow
    71 -- continuous light snow
    72 -- intermittent moderate snow
    73 -- continuous moderate snow
    74 -- intermittent heavy snow
    75 -- continuous heavy snow
    76 -- diamond dust
    77 -- snow grains
    78 -- snow crystals
    79 -- ice pellets
    Showers
    80 -- light rain showers
    81 -- moderate to heavy rain showers
    82 -- violent rain showers
    83 -- light rain and snow showers
    84 -- moderate to heavy rain and snow showers
    85 -- light snow showers
    86 -- moderate to heavy snow showers
    87 -- light snow/ice pellet showers
    88 -- moderate to heavy snow/ice pellet showers
    89 -- light hail showers
    90 -- moderate to heavy hail showers
    Thunderstorms
    91 -- thunderstorm in past hour, currently only light rain
    92 -- thunderstorm in past hour, currently only moderate to heavy rain
    93 -- thunderstorm in past hour, currently only light snow or rain/snow mix
    94 -- thunderstorm in past hour, currently only moderate to heavy snow or rain/snow mix
    95 -- light to moderate thunderstorm
    96 -- light to moderate thunderstorm with hail
    97 -- heavy thunderstorm
    98 -- heavy thunderstorm with duststorm
    99 -- heavy thunderstorm with hail

    W1 -- Past weather (type 1)
    W2 -- Past weather (type 2)

    0 -- cloud covering less than half of sky
    1 -- cloud covering more than half of sky during part of period and more than half during part of period
    2 -- cloud covering more thna half of sky
    3 -- sandstorm, duststorm or blowing snow
    4 -- fog, or thick haze
    5 -- drizzle
    6 -- rain
    7 -- snow or mixed rain and snow
    8 -- showers
    9 -- thunderstorms
  • 8NCCC -- Cloud type information
    N -- Amount of low clouds covering sky, if no low clouds, the amount of the middle clouds
    CL -- Low cloud type
    0 -- no low clouds
    1 -- cumulus humulis or fractus (no vertical development)
    2 -- cumulus mediocris or congestus (moderate vertical development)
    3 -- cumulonimbus calvus (no outlines nor anvil)
    4 -- stratocumulus cumulogenitus (formed by spreading of cumulus)
    5 -- stratocumulus
    6 -- stratus nebulosus (continuous sheet)
    7 -- stratus or cumulus fractus (bad weather)
    8 -- cumulus and stratocumulus (multilevel)
    9 -- cumulonimbus with anvil
    / -- low clouds unobserved due to darkness or obscuration

    CM -- Middle cloud type

    0 -- no middle clouds
    1 -- altostratus translucidous (mostly transparent)
    2 -- altostratus opacus or nimbostratus
    3 -- altocumulus translucidous (mostly transparent)
    4 -- patches of altocumulus (irregular, lenticular)
    5 -- bands of altocumulus
    6 -- altocumulus cumulogenitus (formed by spreading of cumulus)
    7 -- altocumulus (multilayers)
    8 -- altocumulus castellanus (having cumuliform tufts)
    9 -- altocumulus of a chaotic sky
    / -- middle clouds unobserved due to darkness or obscuration

    CH -- High cloud type

    0 -- no high clouds
    1 -- cirrus fibratus (wispy)
    2 -- cirrus spissatus (dense in patches)
    3 -- cirrus spissatus cumulogenitus (formed out of anvil)
    4 -- cirrus unicus or fibratus (progressively invading sky)
    5 -- bands of cirrus or cirrostratus invading sky (less than 45 degree above horizon)
    6 -- bands of cirrus or cirrostratus invading sky (more than 45 degree above horizon)
    7 -- cirrostratus covering whole sky
    8 -- cirrostratus not covering sky but not invading
    9 -- cirrocumulus
    / -- high clouds unobserved due to darkness or obscuration
  • 9GGgg -- Time of observation in hours and minutes


222 Group - Sea Surface Observations

  • 222Dv
    D -- direction of ship movement
    0 -- calm
    1 -- NE
    2 -- E
    3 -- SE
    4 -- S
    5 -- SW
    6 -- W
    7 -- NW
    8 -- N
    9 -- unknown
  • v -- ship's average speed
    0 -- 0 knots
    1 -- 1 to 5 knots
    2 -- 6 to 10 knots
    3 -- 11 to 15 knots
    4 -- 16 to 20 knots
    5 -- 21 to 25 knots
    6 -- 26 to 30 knots
    7 -- 31 to 35 knots
    8 -- 36 to 40 knots
    9 -- over 40 knots
  • 0sTTT -- Sea surface temperature
    s -- sign of temperature (0=positive, 1=negative)
    TTT -- Temperature in .1 C
  • 1PPHH -- Wave heights in 0.5 m increments
    PP -- Period of waves in seconds
    HH -- Height of waves in 0.5 m increments
  • 2PPHH -- Wave period and heights (instrumented)
  • 3dddd -- Direction of swells (up to 2 swells)
  • 4PPHH -- Period and direction of first set of swells
  • 5PPHH -- Period and direction of second set of swells
  • 6IEER -- Ice accretion on ships
  • 70HHH -- Wave heights to 0.1 m (instrumented)
  • 8aTTT -- Wet bulb temperature


333 Group - Special / Climatological Data

  • 0.... -- Regionally developed data
  • 1sTTT -- Maximum temperature over previous 24 hours
    s -- sign of temperature (0=positive, 1=negative)
    TTT -- Temperature in .1 C
  • 2sTTT -- Minimum temperature over previous 24 hours
    s -- sign of temperature (0=positive, 1=negative)
    TTT -- Temperature in .1 C
  • 3Ejjj -- Regionally developed data
  • 4Esss -- Snow depth
    E -- State of ground with snow cover
    0 -- predominantly covered with ice
    1 -- compact or wet snow covering less than half of ground
    2 -- compact or wet snow covering more than half of ground but not completely covered
    3 -- even layer of compact or wet snow covering entire ground
    4 -- uneven layer of compact or wet snow covering entire ground
    5 -- loose dry snow covering less than half of ground
    6 -- loose dry snow covering more than half of ground but not completely covered
    7 -- even layer of loose dry snow covering entire ground
    8 -- uneven layer of loose dry snow covering entire ground
    9 -- snow covering ground completely with deep drifts

    sss -- snow depth in cm

  • 5jjjj jjjjj -- Additional information (can be multiple groups)
  • 6RRRt -- Liquid precipitation
    RRR -- Precipitation amount in mm
    001 -- 1 mm
    002 -- 2 mm
    ...
    988 -- 988 mm
    989 -- 989 or more mm
    990 -- Trace
    991 -- 0.1 mm
    992 -- 0.2 mm
    ...
    999 -- 0.9 mm
  • t -- Duration over which precipitation amount measured
    1 -- 6 hours
    2 -- 12 hours
    3 -- 18 hours
    4 -- 24 hours
    5 -- 1 hour
    6 -- 2 hours
    7 -- 3 hours
    8 -- 9 hours
    9 -- 15 hours
    / -- 24 hours
  • 7RRRR -- 24 hour precipitation in mm
  • 8NChh -- Cloud layer data
    N -- cloud coverage of layer
    C -- genus of cloud
    0 -- cirrus (Ci)
    1 -- cirrocumulus (Cc)
    2 -- cirrostratus (Cs)
    3 -- altocumulus (Ac)
    4 -- altostratus (As)
    5 -- nimbostratus (Ns)
    6 -- stratocumulus (Sc)
    7 -- stratus (St)
    8 -- cumulus (Cu)
    9 -- cumulonimbus (Cb)
    / -- cloud not visible
  • hh -- height of cloud base
    00 -- less than 30 m
    01 -- 30 m (100 ft)
    02 -- 60 m (200 ft)
    03 -- 90 m (300 ft)
    ...
    50 -- 1500 m (5000 ft)
    56 -- 1800 m (6000 ft)
    57 -- 2100 m (7000 ft)
    ...
    80 -- 9000 m (30000 ft)
    81 -- 10500 m
    82 -- 12000 m
    ...
    88 -- 21000 m
    89 -- greater than 21000 m
    90 -- 0 to 50 m
    91 -- 50 to 100 m
    92 -- 100 to 200 m
    93 -- 200 to 300 m
    94 -- 300 to 600 m
    95 -- 600 to 1000 m
    96 -- 1000 to 1500 m
    97 -- 1500 to 2000 m
    98 -- 2000 to 2500 m
    99 -- above 2500 m
  • 9SSss -- Supplementary information