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Glossary of parameters

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Found 257 parameters

  1. Air temperature at 1.5m

    Temperature at screen level. Stevenson screen height is approximately 1.5m above ground level.

  2. Air temperature at 1.5m - day max

    This is the most likely maximum value over the day based on the ensemble spread. Stevenson screen height is approximately 1.5m above ground level. Daytime is defined as those forecast times that fall between local dawn and dusk.

  3. Air temperature at 1.5m - day max - lower bound

    This is the lower bound for the maximum value over the day based on the ensemble spread. It is actually given by the 2.5 percentile. This means there is a 97.5% probability that the actual figure will be above this lower bound figure. Stevenson screen height is approximately 1.5m above ground level. Daytime is defined as those forecast times that fall between local dawn and dusk.

  4. Air temperature at 1.5m - day max - upper bound

    This is the upper bound for the maximum value over the day based on the ensemble spread. It is actually given by the 97.5 percentile. This means there is a 97.5% probability that the actual figure will be below this upper bound figure. Stevenson screen height is approximately 1.5m above ground level. Daytime is defined as those forecast times that fall between local dawn and dusk.

  5. Air temperature at 1.5m - night min

    This is the most likely minimum value over the night based on the ensemble spread. Stevenson screen height is approximately 1.5m above ground level. Night-time is defined as those forecast times that fall between local dusk and dawn

  6. Air temperature at 1.5m - night min - lower bound

    This is the lower bound for the minimum value over the night based on the ensemble spread. It is actually given by the 2.5 percentile. This means there is a 97.5% probability that the actual figure will be above this lower bound figure. Stevenson screen height is approximately 1.5m above ground level. Night-time is defined as those forecast times that fall between local dusk and dawn.

  7. Air temperature at 1.5m - night min - upper bound

    This is the most likely minimum value over the night based on the ensemble spread. Stevenson screen height is approximately 1.5m above ground level. Night-time is defined as those forecast times that fall between local dusk and dawn.

  8. Cloud below 1,000 feet

    0-6-195 (local)

    Fraction of horizontal grid square occupied by cloud below 1,000 feet above sea level.

  9. Cloud cover

    0-6-22

    Fraction of horizontal grid square occupied by cloud in layers centred on height levels.

  10. Cloud cover

    0-6-22

    Fraction of horizontal grid square occupied by cloud in layers centred on pressure levels.

  11. Cloud water mixing ratio

    0-1-192 (local)

    Ratio of the mass of liquid water to the mass of dry air on pressure levels.

  12. Cloud water mixing ratio

    0-1-192 (local)

    Ratio of the mass of liquid water to the mass of dry air on height levels. The levels are height above ground

  13. Convective cloud cover

    0-6-2

    Fraction of horizontal grid square occupied by cloud in the pressure range centred on the pressure level (from halfway between the level below and the current level and halfway between the current level and the level above)

  14. Convective cloud cover

    0-6-2

    Fraction of horizontal grid square occupied by convective cloud as diagnosed by the model convection scheme. This is for the whole atmosphere column as seen from the surface or the top of the atmosphere.

  15. Convective cloud cover

    0-6-2

    Fraction of horizontal grid square occupied by cloud in the height range centred on the height level (from halfway between the level below and the current level and halfway between the current level and the level above)

  16. Convective rain rate

    0-1-76

    Instantaeneous rate at which rain, produced by the model convection scheme, is being deposited on the surface. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  17. Convective rain rate - 1 hour average

    0-1-76

    Mean rate at which rain, produced by the model convection scheme, is being deposited on the surface in the previous hour. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  18. Convective rain rate - 1 hour maximum

    0-1-76

    Maximum instantaneous rate at which rain, produced by the model convection scheme, is being deposited on the surface in the previous hour. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  19. Convective rain rate - 3 hour average

    0-1-76

    Mean rate at which rain, which has been produced by the model convection scheme, is being deposited on the surface in the previous 3 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  20. Convective rain rate - 3 hour maximum

    0-1-76

    Maximum instantaneous rate at which rain, produced by the model convection scheme, is being deposited on the surface in the previous 3 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  21. Convective rain rate - 6 hour average

    0-1-76

    Mean rate at which rain, which has been produced by the model convection scheme, is being deposited on the surface in the previous 6 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  22. Convective rain rate - 6 hour maximum

    0-1-76

    Maximum instantaneous rate at which rain, produced by the model convection scheme, is being deposited on the surface in the previous 6 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  23. Convective snowfall rate

    0-1-55

    Rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous hour. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  24. Convective snowfall rate - 1 hour

    0-1-55

    Mean rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous hour. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  25. Convective snowfall rate - 1 hour maximum

    0-1-55

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous hour. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  26. Convective snowfall rate - 3 hour

    0-1-55

    Mean rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous 3 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  27. Convective snowfall rate - 3 hour maximum

    0-1-55

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous 3 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  28. Convective snowfall rate - 6 hour

    0-1-55

    Mean rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous 6 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  29. Convective snowfall rate - 6 hour maximum

    0-1-55

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous 6 hours. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  30. Dew point temperature at 1.5m

    0-0-6

    Dew point temperature (temperature at which a parcel of air reaches saturation upon being cooled at constant pressure and specific humidity) at screen level

  31. Dew point temperature at 1.5m (Spot)

    Dew point temperature at 1.5m. Stevenson screen height is approximately 1.5m above ground level.

  32. Diffuse shortwave radiation flux

    0-4-14

    Shortwave radiation at the surface from above directed at the ground. “Diffuse” means that the radiation has been scattered by particles in the atmosphere such as cloud droplets and aerosols. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.

  33. Direct shortwave radiation flux

    0-4-13

    Shortwave radiation at the surface from above directed at the ground. ”Direct” means that the radiation has followed a direct path from the sun and is alternatively known as “direct insolation”. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.

  34. Downward UV radiation

    0-4-12

    Ultaviolet radiation at the surface from above directed at the ground. In accordance with common usage in geophysical disciplines flux implies per unit area called "flux density" in physics.

  35. Downward longwave radiation flux

    0-5-3

    Longwave radiation at the surface from above directed at the ground. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics.

  36. Downward shortwave radiation flux at surface

    0-4-7

    Shortwave radiation at the surface from above directed at the ground. "Total" means the sum of direct and diffuse solar radiation incident on the surface and is sometimes called "global radiation". In accordance with common usage in geophysical disciplines "flux" implies per unit area called "flux density" in physics. Unlike the other radiation parameters this parameter has not been adjusted to a model time step and so represents a mean radition time step value (the hour following the validaity time for the model)

  37. Dust mass mixing ratio (division 1)

    0-13-193 (local)

    Mass ratio of dust particules to air on pressure levels. Dust particles are split into 2 sizes ranges. Bin 1 has particules in the range 0.2 - 4.0 microns (μm) in diameter.

  38. Dust mass mixing ratio (division 1)

    0-13-193 (local)

    Mass ratio of dust particules to air on height levels. Dust particles are split into 2 sizes ranges. Bin 1 has particules in the range 0.2 - 4.0 microns (μm) in diameter. The levels are height above ground.

  39. Dust mass mixing ratio (division 2)

    0-13-194 (local)

    Mass ratio of dust particules to air on height levels. Dust particles are split into 2 sizes ranges. Bin 2 has particules in the range 4.0 - 20.0 microns (μm) in diameter. The levels are height above ground.

  40. Dust mass mixing ratio (division 2)

    0-13-194 (local)

    Mass ratio of dust particules to air on pressure levels. Dust particles are split into 2 sizes ranges. Bin 2 has particules in the range 4.0 - 20.0 microns (μm) in diameter.

  41. Evaporation rate

    0-1-79

    Rate of loss of water from the surface expressed as a mass flux.

  42. Falling snow amount - 1 hour

    This is the amount of snow that has fallen out of the sky in the last hour. This does not reflect snow lying on the ground. Falling snow may not settle at all and may be accompanied by rain, i.e. is sleet. Falling snow amount is stated as liquid water equivalent in mm which can be considered approximately the same as cm of fresh snow or a kg/m^2.

  43. Falling snow amount - 3 hours

    This is the amount of snow that has fallen out of the sky in the last 3 hours. This does not reflect snow lying on the ground. Falling snow may not settle at all and may be accompanied by rain, i.e. is sleet. Falling snow amount is stated as liquid water equivalent in mm which can be considered approximately the same as cm of fresh snow or a kg/m^2.

  44. Feels like temperature

    The temperature it feels like taking into account humidity and wind chill but not radiation

  45. Feels like temperature - day max

    This is the most likely maximum value over the day based on the ensemble spread. This is the temperature it feels like taking into account humidity and wind chill but not radiation. Daytime is defined as those forecast times that fall between local dawn and dusk.

  46. Feels like temperature - day max - lower bound

    This is the lower bound for the maximum value over the day based on the ensemble spread. It is actually given by the 2.5 percentile. This means there is a 97.5% probability that the actual figure will be above this lower bound figure. This is the temperature it feels like taking into account humidity and wind chill but not radiation. Daytime is defined as those forecast times that fall between local dawn and dusk.

  47. Feels like temperature - day max - upper bound

    This is the upper bound for the maximum value over the day based on the ensemble spread. It is actually given by the 97.5 percentile. This means there is a 97.5% probability that the actual figure will be below this upper bound figure. This is the temperature it feels like taking into account humidity and wind chill but not radiation. Daytime is defined as those forecast times that fall between local dawn and dusk.

  48. Feels like temperature - night min

    This is the most likely minimum value over the night based on the ensemble spread. This is the temperature it feels like taking into account humidity and wind chill but not radiation. Night-time is defined as those forecast times that fall between local dusk and dawn.

  49. Feels like temperature - night min - lower bound

    This is the lower bound for the minimum value over the night based on the ensemble spread. It is actually given by the 2.5 percentile. This means there is a 97.5% probability that the actual figure will be above this lower bound figure. This is the temperature it feels like taking into account humidity and wind chill but not radiation. Night-time is defined as those forecast times that fall between local dusk and dawn.

  50. Feels like temperature - night min - upper bound

    This is the upper bound for the minimum value over the night based on the ensemble spread. It is actually given by the 97.5 percentile.  This means there is a 97.5% probability that the actual figure will be below this upper bound figure. This is the temperature it feels like taking into account humidity and wind chill but not  radiation. Night-time is defined as those forecast times that fall between local dusk and dawn.

  51. Fog fraction at 1.5m

    0-6-32 (mapped)

    Fog means a visibility of 1000 m or lower. The reduction in visibility is caused water droplets or minute ice crystals forming close to the surface. This quantity represents the fraction of horizontal grid square occupied by fog. An alternative interpretation is that this represents the fractional probability of fog being present at any location in the grid square. There is no WMO GRIB2 code for fog, it is mapped to cloud to aid usability.

  52. Geometric height

    0-3-33

    Height above ground level (the surface) of the pressure levels.

  53. Geometric height (DO NOT USE)

    0-3-6

    To be deprecated Aug-22. Height above ground level (the surface) of the pressure levels.

  54. Geopotential height

    0-3-5

    Height above mean sea level or altitude of the pressure levels. This is considered approximately equivalent to geopotential height. Geopotential is the sum of the specific gravitational potential energy relative to the geoid and the specific centripetal potential energy. Geopotential height is the geopotential divided by the standard acceleration due to gravity.

  55. Hail fall accumulation - 1 hour

    0-1-73

    Implied depth of the layer of liquid water equivalent (LWE) hail produced by the model precipitation scheme which has been deposited on the surface in previous hour. This includes both large hail and small hail (often called graupel).

  56. Hail fall accumulation - 3 hour

    0-1-73

    Implied depth of the layer of liquid water equivalent (LWE) hail produced by the model precipitation scheme which has been deposited on the surface in previous three hours. This includes both large hail and small hail (often called graupel).

  57. Hail fall rate

    0-1-73

    Instantaneous rate at which liquid water equivalent (LWE) hail (as a depth) which has been produced by the model precipitation scheme is being deposited on the surface. This includes both large hail and small hail (often called graupel).

  58. Hail fall rate - 1 hour maximum

    0-1-73

    Maximum instantaneous rate at which liquid water equivalent (LWE) hail (as a depth) which has been produced by the model precipitation scheme was being deposited on the surface in previous hour. This includes both large hail and small hail (often called graupel).

  59. Hail fall rate - 3 hour maximum

    0-1-73

    Maximum instantaneous rate at which liquid water equivalent (LWE) hail (as a depth) which has been produced by the model precipitation scheme was being deposited on the surface in previous 3 hours. This includes both large hail and small hail (often called graupel)

  60. Height (AGL) at freezing level

    0-3-33

    Height of the 0degC isotherm (freezing level) above the surface (ground).

  61. Height (AGL) at freezing level (DO NOT USE)

    0-3-6

    To be deprecated Aug-22. Height of the 0degC isotherm (freezing level) above the surface (ground).

  62. Height (AGL) of 0p1 oktas cloud base

    0-3-6

    To be deprecated Aug-22. Height of the base of the lowest cloud above the surface (ground) where there is at least 0.1 oktas (eighths) of cloud cover. This is effectively the lowest height at which any cloud is present.

  63. Height (AGL) of 0p1 oktas cloud base (DO NOT USE)

    0-3-6

    To be deprecated Aug-22. Height of the base of the lowest cloud above the surface (ground) where there is at least 0.1 oktas (eighths) of cloud cover. This is effectively the lowest height at which any cloud is present.

  64. Height (AGL) of 2p5 oktas cloud base

    0-3-6

    To be deprecated Aug-22. Height of the base of the lowest cloud above the surface (ground) where there is at least 2.5 oktas (eighths) of cloud cover. This corresponds to scattered cloud.

  65. Height (AGL) of 2p5 oktas cloud base (DO NOT USE)

    0-3-6

    To be deprecated Aug-22. Height of the base of the lowest cloud above the surface (ground) where there is at least 2.5 oktas (eighths) of cloud cover. This corresponds to scattered cloud.

  66. Height (AGL) of 4p5 oktas cloud base

    0-3-6

    To be deprecated Aug-22. Height of the base of the lowest cloud above the surface (ground) where there is at least 4.5 oktas (eighths) of cloud cover. This corresponds to broken cloud.

  67. Height (AGL) of 4p5 oktas cloud base (DO NOT USE)

    0-3-6

    To be deprecated Aug-22. Height of the base of the lowest cloud above the surface (ground) where there is at least 4.5 oktas (eighths) of cloud cover. This corresponds to broken cloud.

  68. Height (AGL) of wet bulb freezing level

    0-3-33

    Height of the wet bulb freezing level (i.e. where the wet bulb temperature is 0degC) above the surface (ground). This is also referred to as the altitude of the wet bulb freezing level or (geometric) height above the geoid which is the reference geopotential surface. Wet bulb temperature is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the evaporation of water into it with the latent heat supplied by the parcel

  69. Height (AGL) of wet bulb freezing level (DO NOT USE)

    0-3-6

    To be deprecated Aug-22. Height of the wet bulb freezing level (i.e. where the wet bulb temperature is 0degC) above the surface (ground). This is also referred to as the altitude of the wet bulb freezing level or (geometric) height above the geoid which is the reference geopotential surface. Wet bulb temperature is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the evaporation of water into it with the latent heat supplied by the parcel

  70. Height (ASL) at base of convective inflow

    0-3-5

    Effective inflow layer base height is the height of the first level which during the most unstable parcel ascent satisfies the condition that CAPE > 100 J/kg and CIN > 250 J/kg.

  71. Height (ASL) at mixed layer CAPE equilibrium level

    0-3-5

    Mixed layer equilibrium level height above mean sea level where mixed layer parcel temperature equals the environment temperature above mean layer level of free convection (MLLFC).

  72. Height (ASL) at most unstable CAPE equilibrium level

    0-3-5

    Most unstable equilibrium level height above mean sea level where the most unstable parcel temperature equals the environment temperature above its level of free convection.

  73. Height (ASL) at top of convective inflow

    0-3-5

    Effective inflow layer top height is the height of the first level which during the most unstable parcel ascent no longer satisfies the condition CAPE > 100 J/kg and CIN > 250 J/kg.

  74. Height (ASL) of 2p5 oktas cloud base

    0-3-5

    To be deprecated Aug-22. Height of the base of the lowest cloud above sea level where there is at least 2.5 oktas (eighths) of cloud cover. This is also referred to as the altitude of the cloud base or (geometric) height above the geoid which is the reference geopotential surface. This corresponds to scattered cloud.

  75. Height (ASL) of 2p5 oktas cloud base (DO NOT USE)

    0-3-5

    To be deprecated Aug-22. Height of the base of the lowest cloud above sea level where there is at least 2.5 oktas (eighths) of cloud cover. This is also referred to as the altitude of the cloud base or (geometric) height above the geoid which is the reference geopotential surface. This corresponds to scattered cloud.

  76. Height (ASL) of 2p5 oktas cloud base (New)

    0-3-32

    Height of the base of the lowest cloud above sea level where there is at least 2.5 oktas (eighths) of cloud cover. This is also referred to as the altitude of the cloud base or (geometric) height above the geoid which is the reference geopotential surface. This corresponds to scattered cloud.

  77. Height (ASL) of 4p5 oktas cloud base

    0-3-5

    To be deprecated Aug-22. Height of the base of the lowest cloud above sea level where there is at least 4.5 oktas (eighths) of cloud cover. This is also referred to as the altitude of the cloud base or (geometric) height above the geoid which is the reference geopotential surface. This corresponds to broken cloud.

  78. Height (ASL) of 4p5 oktas cloud base (DO NOT USE)

    0-3-5

    To be deprecated Aug-22. Height of the base of the lowest cloud above sea level where there is at least 4.5 oktas (eighths) of cloud cover. This is also referred to as the altitude of the cloud base or (geometric) height above the geoid which is the reference geopotential surface. This corresponds to broken cloud.

  79. Height (ASL) of 4p5 oktas cloud base (New)

    0-3-32

    Height of the base of the lowest cloud above sea level where there is at least 4.5 oktas (eighths) of cloud cover. This is also referred to as the altitude of the cloud base or (geometric) height above the geoid which is the reference geopotential surface. This corresponds to broken cloud.

  80. Height (ASL) of freezing level

    0-3-5

    Height of the 0 degree C isotherm (freezing level) above sea level. This is also referred to as the altitude of the freezing level or (geometric) height above the geoid.

  81. Height (ASL) of most unstable departure level

    0-3-192 (local)

    Departure level of the most unstable parcel of air (MUDL)

  82. Height (ASL) of wet bulb freezing level

    0-3-32

    Height of the wet bulb freezing level (i.e. where the wet bulb temperature is 0degC) above sea level. This is also referred to as the altitude of the wet bulb freezing level or (geometric) height above the geoid which is the reference geopotential surface. Wet bulb temperature is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the evaporation of water into it with the latent heat supplied by the parcel.

  83. Height (ASL) of wet bulb freezing level (DO NOT USE)

    0-3-5

    To be deprecated Aug-22. Height of the wet bulb freezing level (i.e. where the wet bulb temperature is 0degC) above sea level. This is also referred to as the altitude of the wet bulb freezing level or (geometric) height above the geoid which is the reference geopotential surface. Wet bulb temperature is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the evaporation of water into it with the latent heat supplied by the parcel.

  84. High cloud cover

    0-6-5

    Fraction of horizontal grid square occupied by cloud in the high-level cloud height range; from 5,574m (~18,000ft) to 13,608m (~44,500ft).

  85. Landsea mask

    2-0-0

    Indicator of whether a point is considered land (value = 1) or sea (value = 0).

  86. Landsea mask (Map)

    2-0-0

    Indicator of whether a point is considered land (value = 1) or sea (value = 0).

  87. Large scale rain rate

    0-1-77

    Instantaneous rate at which rain, produced by the model precipitation scheme, is being deposited on the surface. For the Global models (which run a convection scheme) the "rainfall rate from convection" must be added to this to get the total rainfall rate (this is not required for the UK models as they do not run a convection scheme). A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units)

  88. Large scale rain rate - 1 hour maximum

    0-1-77

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow, produced by the model convection scheme, is being deposited on the surface in previous hour. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  89. Large scale rain rate - 3 hour maximum

    0-1-77

    Maximum instantaneous rate at which rain (as a depth) which has been produced by the model precipitation scheme was being deposited on the surface in previous hour. This excludes the rain produced by the the model convection scheme so for Global models (which invoke the convection scheme) this is not a maximum total rainfall rate.

  90. Large scale rain rate - 6 hour maximum

    0-1-77

    Maximum instantaneous rate at which rain, produced by the model precipitation scheme, is being deposited on the surface in previous 6 hours. This excludes the rain produced by the the model convection scheme, so for Global models (which invoke the convection scheme), this is not a maximum total rainfall rate. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  91. Large scale snowfall rate

    0-1-56

    Instantaneous rate at which liquid water equivalent (LWE) snow, produced by the model precipitation scheme, is being deposited on the surface. For the Global models (which run a convection scheme), the "snowfall rate from convection" must be added to this to get the total snowfall rate (this is not required for the UK models as they do not run a convection scheme). A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  92. Large scale snowfall rate - 1 hour maximum

    0-1-56

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow, produced by the model precipitation scheme, is being deposited on the surface in the previous hour. This excludes the snow produced by the the model convection scheme so for Global models (which invoke the convection scheme), this is not a maximum total snowfall rate. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  93. Large scale snowfall rate - 3 hour maximum

    0-1-56

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow, produced by the model precipitation scheme, is being deposited on the surface in previous 3 hours. This excludes the snow produced by the the model convection scheme so for Global models (which invoke the convection scheme), this is not a maximum total snowfall rate. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  94. Large scale snowfall rate - 6 hour maximum

    0-1-56

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow , produced by the model precipitation scheme, is being deposited on the surface in previous 6 hours. This excludes the snow produced by the the model convection scheme so for Global models (which invoke the convection scheme), this is not a maximum total snowfall rate. A scaling factor of 1000 is used to convert m s-1 (the units received from source) to kg m-2 s-1 (GRIB2 units).

  95. Latent heat net flux - 1 hour average

    0-0-10

    Exchange of heat between the surface and the air by motion of air; also called “turbulent” heat flux. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics. Upwards is positive; negative is downward. Mean in the previous hour.

  96. Latent heat net flux - 3 hour average

    0-0-10

    Exchange of heat between the surface and the air on account of evaporation (including sublimation). In accordance with common usage in geophysical disciplines "flux" implies per unit area called "flux density" in physics. Upwards is positive; negative is downward. Mean in previous 3 hours.

  97. Latent heat net flux - 6 hour average

    0-0-10

    Exchange of heat between the surface and the air on account of evaporation (including sublimation). In accordance with common usage in geophysical disciplines "flux" implies per unit area called "flux density" in physics. Upwards is positive; negative is downward. Mean in previous 6 hours.

  98. Lightning flash accumulation - 1 hour

    0-17-192 (local)

    Number of lightning flashes per square metre in the previous hour.

  99. Lightning flash accumulation - 3 hour

    0-17-192 (local)

    Number of lightning flashes per square metre in the previous three hours. Note due to time step availability and run lengths this parameter is only returned for the 03:00 and 15:00 model runs.

  100. Low cloud cover

    0-6-3

    Fraction of horizontal grid square occupied by cloud in the low-level cloud height range: from 111m (~350ft) to 1949m (~6,500ft).

  101. Maximum temperature at 1.5m - 1 hour

    0-0-0

    Maximum instantaneous air temperature at screen level (1.5m) in the previous hour.

  102. Maximum temperature at 1.5m - 1 hour (Spot)

    Maximum air temperature at screen level. Stevenson screen height is approximately 1.5m above ground level.

  103. Maximum temperature at 1.5m - 3 hour

    0-0-0

    Maximum instantaneous air temperature at screen level (1.5m) in the previous three hours.

  104. Maximum temperature at 1.5m - 3 hour (Spot)

    Maximum air temperature at screen level. Stevenson screen height is approximately 1.5m above ground level.

  105. Maximum temperature at 1.5m - 6 hour

    0-0-0

    Maximum instantaneous air temperature at screen level (1.5m) in the previous six hours.

  106. Mean sea level pressure

    Air pressure at mean sea level which is close to the geoid in sea areas. Air pressure at sea level is the quantity often abbreviated as MSLP or PMSL.

  107. Mean sea level pressure (Spot)

    Air pressure at mean sea level which is close to the geoid in sea areas. Air pressure at sea level is the quantity often abbreviated as MSLP or PMSL.

  108. Mean sea level pressure - midday

    Air pressure at mean sea level which is close to the geoid in sea areas. Air pressure at sea level is the quantity often abbreviated as MSLP or PMSL.

  109. Mean sea level pressure - midnight

    Air pressure at mean sea level which is close to the geoid in sea areas. Air pressure at sea level is the quantity often abbreviated as MSLP or PMSL.

  110. Medium cloud cover

    0-6-4

    Fraction of horizontal grid square occupied by cloud in the mid-level cloud height range; from 1,949m (~6,500ft) to 5,574m (~18,000ft).

  111. Minimum temperature at 1.5m - 1 hour

    0-0-0

    Minimum instantaneous air temperature at screen level (1.5m) in the previous hour.

  112. Minimum temperature at 1.5m - 1 hour (Spot)

    Minimum air temperature at screen level. Stevenson screen height is approximately 1.5m above ground level.

  113. Minimum temperature at 1.5m - 3 hour

    0-0-0

    Minimum instantaneous air temperature at screen level (1.5m) in previous three hours.

  114. Minimum temperature at 1.5m - 3 hour (Spot)

    Minimum air temperature at screen level. Stevenson screen height is approximately 1.5m above ground level.

  115. Minimum temperature at 1.5m - 6 hour

    0-0-0

    Minimum instantaneous air temperature at screen level (1.5m) in previous six hours.

  116. Mixed layer CAPE (Convective Available Potential Energy)

    0-7-193 (local)

    Convective Available Potential Energy (CAPE) calculated for a parcel with the thermodynamic properties of the density-weighted mean of the lowest 500 m above ground level.

  117. Mixed layer CIN (Convective Inhibition)

    0-7-195 (local)

    Any additional energy required to lift a mixed-layer parcel to its level of free convection. Where a mixed layer parcel is defined as parcel with thermodynamic properties of the density weighted mean of the lowest 500 m above ground level (AGL).

  118. Most Unstable CAPE (Convective Available Potential Energy)

    0-7-192 (local)

    CAPE (Convective Available Potential Energy) calculated for the most unstable parcel where the most unstable parcel is defined as the parcel with the highest fixed level CAPE launched from any level (including screen-level=1.5m) within 500hPa of the surface pressure.

  119. Most Unstable CIN (Convective Inhibition)

    0-7-194 (local)

    Any additional energy required to lift the most unstable parcel to its level of free convection. Where most unstable parcel is defined as the parcel with the highest fixed-level CAPE launched from any level (including screen-level) within 500 hPa of the surface pressure.

  120. Net shortwave radiation flux

    0-4-9

    Shortwave radiation at the surface from above directed at the ground. Net downward radiation is the difference between radiation from above (downwelling) and radiation from below (upwelling). In accordance with common usage in geophysical disciplines "flux" implies per unit area called "flux density" in physics.

  121. Planetary boundary layer height

    0-3-18

    “Depth” or “height” of the (atmosphere) planetary boundary layer the part of the atmosphere whose behaviour is directly influenced by its contact with a planetary surface.

  122. Plant canopy surface water

    2-0-13

    Water held on vegetation expressed as a mass per unit area.

  123. Precipitation accumulation - 1 hour

    0-1-52

    Implied depth of the layer of liquid water which has been deposited on the surface in the previous hour. This includes rain, snow and hail with the ice phase precipitation being considered as a liquid water equivalent (lwe) value. It includes the contribution from the model convection scheme if this is invoked (true for Global models but not the UK models) as well as that from the model precipitation scheme.

  124. Precipitation accumulation - 1 hour (Spot)

    Implied depth of the layer of liquid water which has been deposited on the surface since the previous hour.

  125. Precipitation accumulation - 3 hour

    0-1-52

    Implied depth of the layer of liquid water which has been deposited on the surface in the previous 3 hours. This includes rain, snow and hail with the ice phase precipitation being considered as a liquid water equivalent (lwe) value. It includes the contribution from the model convection scheme if this is invoked (true for Global models but not the UK models) as well as that from the model precipitation scheme.

  126. Precipitation accumulation - 3 hours (Spot)

    Implied depth of the layer of liquid water which has been deposited on the surface in the previous 3 hours.

  127. Precipitation accumulation - 6 hour

    0-1-52

    Implied depth of the layer of liquid water which has been deposited on the surface in the previous 6 hours. This includes rain, snow and hail with the ice phase precipitation being considered as a liquid water equivalent (lwe) value. It includes the contribution from the model convection scheme if this is invoked (true for Global models but not the UK models) as well as that from the model precipitation scheme

  128. Precipitation rate (Spot)

    Instantaneous rate at which liquid water (as a depth) is being deposited on the surface.

  129. Pressure

    0-3-0

    Pressure at the height levels. These are height above ground (model orography).

  130. Pressure at convective cloud base

    0-3-0

    Air pressure at the base of the lowest convective cloud that diagnosed by the model convection scheme.

  131. Pressure at convective cloud top

    0-3-0

    Air pressure at the top of the highest convective cloud that diagnosed by the model convection scheme

  132. Pressure at freezing level

    0-3-0

    Air pressure at the 0 degrees C isotherm (freezing level).

  133. Pressure at maximum wind speed level

    0-3-0

    Air pressure at level in the vertical where the maximum wind speed occurs.

  134. Pressure at surface

    0-3-0

    Air pressure at the surface (lower boundary of the atmosphere).

  135. Pressure at tropopause

    0-3-0

    Air pressure at tropopause

  136. Pressure reduced to mean sea level

    0-3-1

    Air pressure at mean sea level which is close to the geoid in sea areas. Air pressure at sea level is the quantity often abbreviated as MSLP or PMSL.

  137. Pressure reduced to mean sea level (Map)

    0-3-1

    Air pressure at mean sea level which is close to the geoid in sea areas. Air pressure at sea level is the quantity often abbreviated as MSLP or PMSL.

  138. Probability of Precipitation

    Probabilities are given over the entire time step centered at the validity time.

  139. Probability of hail

    Probability of hail occurring at the validity time.

  140. Probability of hail - day

    Probability of hail during the day. Daytime is defined as those forecast times that fall between local dawn and dusk.

  141. Probability of hail - night

    Probability of hail during the night. Night-time is defined as those forecast times that fall between local dusk and dawn.

  142. Probability of heavy rain

    Probability of heavy rain occurring at the validity time. Heavy rain is defined here as a rate >1mm/hr

  143. Probability of heavy rain - day

    Probability of heavy rain during the day. Heavy rain is defined as >1mm/hr. Daytime is defined as those forecast times that fall between local dawn and dusk.

  144. Probability of heavy rain - night

    Probability of heavy rain during the night. Heavy rain is defined as >1mm/hr. Night-time is defined as those forecast times that fall between local dusk and dawn.

  145. Probability of heavy snow

    Probability of heavy snow occurring at the validity time. Heavy snow is defined here as a rate > 1mm/hr (liquid water equivalent). Approximately equivilent to >1cm snow per hour.

  146. Probability of heavy snow - day

    Probability of heavy snow during the day. Heavy snow is defined as >1mm/hr liquid water equivalent and is approximately equivilent to >1cm snow per hour. Daytime is defined as those forecast times that fall between local dawn and dusk.

  147. Probability of heavy snow - night

    Probability of heavy snow during the night. Heavy snow is defined as >1mm/hr liquid water equivalent and is approximately equivilent to >1cm snow per hour. Daytime is defined as those forecast times that fall between local dawn and dusk.

  148. Probability of lightning

    Probability of lightning occuring at the validity time. This is the probability of a strike within a radius of 50km.

  149. Probability of lightning - day

    This is the probability of a strike within a radius of 50km.

  150. Probability of lightning - night

    This is the probability of a strike within a radius of 50km.

  151. Probability of precipitation

    Probabilities are given over the entire time step centered at the validity time.

  152. Probability of precipitation - day

    Probability of precipitation during the day. Daytime is defined as those forecast times that fall between local dawn and dusk

  153. Probability of precipitation - night

    Probability of rain during the night. Night-time is defined as those forecast times that fall between local dusk and dawn.

  154. Probability of rain

    Probability of rain occurring at the validity time.

  155. Probability of rain - day

    Probability of rain during the day. Daytime is defined as those forecast times that fall between local dawn and dusk

  156. Probability of rain - night

    Probability of rain during the night. Night-time is defined as those forecast times that fall between local dusk and dawn.

  157. Probability of snow

    Probability of snow occurring at the validity time.

  158. Probability of snow - day

    Probability of snow during the day. Daytime is defined as those forecast times that fall between local dawn and dusk

  159. Probability of snow - night

    Probability of snow during the night. Night-time is defined as those forecast times that fall between local dusk and dawn.

  160. Rain precipitation accumulation -1 hour

    0-1-65

    Implied depth of the rain produced by the model precipitation scheme which has been deposited on the surface in the previous hour. For the Global models (which run a convection scheme) the “rainfall accumulation from convection” must be added to this to get the total rainfall accumulation. (This is not required for the UK models as they do not run a convection scheme).

  161. Rain precipitation accumulation -3 hour

    0-1-65

    Implied depth of the rain produced by the model precipitation scheme which has been deposited on the surface in the previous 3 hours. For the Global models (which run a convection scheme) the “rainfall accumulation from convection” must be added to this to get the total rainfall accumulation. (This is not required for the UK models as they do not run a convection scheme).

  162. Rain precipitation rate

    0-1-65

    Instantaneous rate at which rain (as a depth) which has been produced by the model precipitation scheme is being deposited on the surface. For the Global models (which run a convection scheme) the “rainfall rate from convection” must be added to this to get the total rainfall rate. (This is not required for the UK models as they do not run a convection scheme).

  163. Rain precipitation rate - 1 hour maximum

    0-1-65

    Maximum instantaneous rate at which rain (as a depth) which has been produced by the model precipitation scheme was being deposited on the surface in previous hour. This excludes the rain produced by the the model convection scheme so for Global models (which invoke the convection scheme). This is not a maximum total rainfall rate.

  164. Rain precipitation rate - 3 hour maximum

    0-1-65

    Maximum instantaneous rate at which rain (as a depth) which has been produced by the model precipitation scheme was being deposited on the surface in previous 3 hours. This excludes the rain produced by the the model convection scheme so for Global models (which invoke the convection scheme). This is not a maximum total rainfall rate.

  165. Rainfall accumulation - 1 hour

    0-1-77

    Implied depth of the rain produced by the model precipitation scheme which has been deposited on the surface in the previous hour. For the Global models (which run a convection scheme) the “rainfall accumulation from convection” must be added to this to get the total rainfall accumulation (this is not required for the UK models as they do not run a convection scheme)

  166. Rainfall accumulation - 3 hours

    0-1-77

    Implied depth of the rain produced by the model precipitation scheme which has been deposited on the surface in the previous 3 hours. For the Global models (which run a convection scheme) the “rainfall accumulation from convection” must be added to this to get the total rainfall accumulation (this is not required for the UK models as they do not run a convection scheme).

  167. Rainfall accumulation - 6 hours

    0-1-77

    Implied depth of the rain produced by the model precipitation scheme which has been deposited on the surface in the previous 6 hours. For the Global models (which run a convection scheme) the “rainfall accumulation from convection” must be added to this to get the total rainfall accumulation (this is not required for the UK models as they do not run a convection scheme).

  168. Rainfall accumulation from convection (1 hour)

    0-1-76

    Implied depth of the rain produced by the model convection scheme which has been deposited on the surface in the previous hour. The “rainfall accumulation” can be added to this to get the total rainfall accumulation

  169. Rainfall accumulation from convection (3 hour)

    0-1-76

    Implied depth of the rain produced by the model convection scheme which has been deposited on the surface in the previous 3 hours. The “rainfall accumulation” can be added to this to get the total rainfall accumulation.

  170. Rainfall accumulation from convection (6 hour)

    0-1-76

    Implied depth of the rain produced by the model convection scheme which has been deposited on the surface in the previous 6 hours. The “rainfall accumulation” can be added to this to get the total rainfall accumulation.

  171. Relative humidity

    0-1-1

    Fractional relative humidity (ratio of the partial pressure of water vapour to the equilibrium vapour pressure of water) on height levels.

  172. Relative humidity

    0-1-1

    Fractional relative humidity (ratio of the partial pressure of water vapour to the equilibrium vapour pressure of water) on pressure levels.

  173. Relative humidity - midday

    Relative humidity at local midday. Stevenson screen height is approximately 1.5m above ground level.

  174. Relative humidity - midnight

    Relative humidity at local midnight. Stevenson screen height is approximately 1.5m above ground level.

  175. Relative humidity at 1.5m

    0-1-1

    Fractional relative humidity (ratio of the partial pressure of water vapour to the equilibrium vapour pressure of water) at screen level (1.5m above the surface).

  176. Relative humidity at 1.5m (Spot)

    Relative humidity at 1.5m. Stevenson screen height is approximately 1.5m above ground level.

  177. Roughness length

    2-0-1

    Length-scale representation of the roughness of the surface equivalent to the height at which the wind speed theoretically becomes zero. Aka Surface Roughness

  178. Sensible heat net flux

    0-0-11

    Exchange of heat between the surface and the air by motion of air; also called “turbulent” heat flux. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics. Upwards is positive; negative is downward.

  179. Sensible heat net flux - 1 hour average

    0-0-11

    Exchange of heat between the surface and the air by motion of air; also called “turbulent” heat flux. In accordance with common usage in geophysical disciplines “flux” implies per unit area called “flux density” in physics. Upwards is positive; negative is downward. Mean in the previous hour.

  180. Sensible heat net flux - 3 hour average

    0-0-11

    Exchange of heat between the surface and the air by motion of air; also called "turbulent" heat flux. In accordance with common usage in geophysical disciplines "flux" implies per unit area called "flux density" in physics. Upwards is positive; negative is downward. Mean in the previous 3 hours.

  181. Sensible heat net flux - 6 hour average

    0-0-11

    Exchange of heat between the surface and the air by motion of air; also called "turbulent" heat flux. In accordance with common usage in geophysical disciplines "flux" implies per unit area called "flux density" in physics. Upwards is positive; negative is downward. Mean in the previous 6 hours.

  182. Significant weather code

    Each periodic symbol is nominally the weather at each time, but considers both instantaneous (e.g. cloud amount) and period (e.g. max rain rate over the last hour) information from the NWP. So it is to a degree biased towards what is happening in the NWP at that instant, but tries to avoid missing weather that might have passed through the NWP a few timesteps before the hour, so as to avoid situations where showers or fronts get lost between times. Significant weather codes explained

  183. Significant weather code - day

    Daytime is defined as those forecast times that fall between local dawn and dusk. Significant weather codes explained

  184. Significant weather code - night

    Night-time is defined as those forecast times that fall between local dusk and dawn. Significant weather codes explained

  185. Snow depth

    0-1-60

    Liquid water equivalent (LWE) depth of the snow lying on the surface (ground). Typically water is 10 times as dense as snow so multiplying by 10 gives an approximate depth of the snow, although wet snow can be significantly denser and powder snow much less dense. A scaling factor of 1000 is used to convert m (the units received from Science) to kg m-2 (GRIB2 units).

  186. Snowfall accumulation - 1 hour

    0-1-56

    Implied depth of the layer of liquid water equivalent (LWE) snow produced by the model precipitation scheme which has been deposited on the surface in previous hour. For the Global models (which run a convection scheme) the “snowfall accumulation from convection” must be added to this to get the total snowfall accumulation. (This is not required for the UK models as they do not run a convection scheme). GRIB code varies by model to reflect this: 0-1-56 (global) 0-1-53 (UK).

  187. Snowfall accumulation - 3 hour

    0-1-56

    Implied depth of the layer of liquid water equivalent (LWE) snow produced by the model precipitation scheme which has been deposited on the surface in previous 3 hours. For the Global models (which run a convection scheme) the “snowfall accumulation from convection” must be added to this to get the total snowfall accumulation. (This is not required for the UK models as they do not run a convection scheme). GRIB code varies by model to reflect this: 0-1-56 (global) 0-1-53 (UK).

  188. Snowfall accumulation - 6 hour

    0-1-56

    Implied depth of the layer of liquid water equivalent (LWE) snow produced by the model precipitation scheme which has been deposited on the surface in previous 6 hours. For the Global models (which run a convection scheme) the “snowfall accumulation from convection” must be added to this to get the total snowfall accumulation. (This is not required for the UK models as they do not run a convection scheme)

  189. Snowfall accumulation from convection - 1 hour

    0-1-55

    Implied depth of the layer of liquid water equivalent (LWE) snow produced by the model convection scheme which has been deposited on the surface in the previous hour. The “snowfall accumulation” can be added to this to get the total snowfall accumulation.

  190. Snowfall accumulation from convection - 3 hour

    0-1-55

    Implied depth of the layer of liquid water equivalent (LWE) snow produced by the model convection scheme which has been deposited on the surface in the previous 3 hours. The “snowfall accumulation” can be added to this to get the total snowfall accumulation.

  191. Snowfall accumulation from convection - 6 hour

    0-1-55

    Implied depth of the layer of liquid water equivalent (LWE) snow produced by the model convection scheme which has been deposited on the surface in the previous 6 hours. The “snowfall accumulation” can be added to this to get the total snowfall accumulation.

  192. Snowfall rate

    0-1-53

    Instantaneous rate at which liquid water equivalent (LWE) snow (as a depth) which has been produced by the model precipitation scheme is being deposited on the surface. For the Global models (which run a convection scheme) the “snowfall rate from convection” must be added to this to get the total snowfall rate (this is not required for the UK models as they do not run a convection scheme).

  193. Snowfall rate - 1 hour maxiumum

    0-1-53

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow (as a depth) which has been produced by the model precipitation scheme was being deposited on the surface in previous hour. This excludes the snow produced by the the model convection scheme so for Global models (which invoke the convection scheme) this is not a maximum total snowfall rate.

  194. Snowfall rate - 3 hour maximum

    0-1-53

    Maximum instantaneous rate at which liquid water equivalent (LWE) snow (as a depth) which has been produced by the model precipitation scheme was being deposited on the surface in previous 3 hours. This excludes the snow produced by the the model convection scheme so for Global models (which invoke the convection scheme) this is not a maximum total snowfall rate

  195. Soil moisture (⚠ Guidance)

    2-3-19

    Mass per unit area of water in all phases contained in the layer surrounding a soil depth level. Please note there is specific guidance on the utilisation of this parameter - click here

  196. Soil temperature

    2-3-18

    Temperature of the soil at a soil depth level.

  197. Specific humidity at 1.5m

    0-1-0

    Specific humidity (mass fraction of water vapour in (moist) air) at screen level (1.5m).

  198. Surface CAPE (Convective Available Potential Energy)

    0-7-6

    Value of CAPE (Convective Available Potential Energy) calculated for a surface based parcel, where a surface based parcel is defined as a parcel initiated with thermodynamic properties at screen level height (1.5m) i.e. the parcel is launched from screen level.

  199. Surface CIN (Convective Inhibition)

    0-7-7

    Any additional energy required to lift a surface based parcel (i.e. a parcel launched from screen-level (1.5m)) to its level of free convection.

  200. Surface altitude

    2-0-7

    Altitude or (geometric) height above the geoid of the surface (ground).Altitude or (geometric) height above the geoid of the surface (ground). Aka Height of Orography and model terrain height

  201. Temperature

    0-0-0

    Air temperature on pressure levels.

  202. Temperature

    0-0-0

    Air temperature on height levels. These are height above ground

  203. Temperature at 1.5m

    0-0-0

    Air temperature at screen level (1.5m).

  204. Temperature at surface

    0-0-0

    Temperature at the surface interface between the air and the ground.

  205. Temperature at surface (Map)

    0-0-0

    Air temperature at screen level (1.5m).

  206. Temperature at tropopause

    0-0-0

    Temperature at the tropopause

  207. Total cloud cover

    0-6-1

    Fraction of horizontal grid square occupied by cloud as diagnosed by the model cloud scheme. This is for the whole atmosphere column as seen from the surface or the top of the atmosphere.

  208. Total cloud cover (Map)

    0-6-1

    Fraction of horizontal grid square occupied by cloud as diagnosed by the model cloud scheme. This is for the whole atmosphere column as seen from the surface or the top of the atmosphere.

  209. Total precipitation rate

    0-1-52

    Instantaneous rate at which liquid water is being deposited on the surface. This includes rain, snow and hail with the ice phase precipitation being considered as a liquid water equivalent (lwe) value. It includes the contribution from the model convection scheme if this is invoked (true for Global models, but not the UK models) as well as that from the model precipitation scheme.

  210. Total precipitation rate (Map)

    0-1-52

    Instantaneous rate at which liquid water is being deposited on the surface. This includes rain, snow and hail with the ice phase precipitation being considered as a liquid water equivalent (lwe) value. It includes the contribution from the model convection scheme if this is invoked (true for Global models, but not the UK models) as well as that from the model precipitation scheme.

  211. UV Index

    Maximum value over the period. Usually a value from 0 to 13 but higher values are possible in extreme situations. UV Index codes explained

  212. UV index - max day

    Usually a value from 0 to 13 but higher values are possible in extreme situations. Daytime is defined as those forecast times that fall between local dawn and dusk.. UV index codes explained

  213. Upward UV radiation

    0-4-192 (local)

    Ultaviolet radiation at the surface directed away from the ground. In accordance with common usage in geophysical disciplines flux implies per unit area called "flux density" in physics.

  214. Upward longwave radiation flux

    0-5-4

    Longwave radiation at the top of the atmosphere (TOA) directed away from the ground. In accordance with common usage in geophysical disciplines "flux" implies per unit area called "flux density" in physics.

  215. Vertical wind velocity

    0-2-9

    Speed of the vertical component of the air motion at a pressure level. Upwards is positive and downwards is negative.

  216. Vertical wind velocity

    0-2-9

    Speed of the vertical component of the air motion at a height level. Upwards is positive and downwards is negative.

  217. Vertical wind velocity at 700hPa

    0-2-9

    Speed of the vertical component of the air motion at a pressure level. Upwards is positive and downwards is negative.

  218. Visibility - midday

    Visibility at local midday. Minimal horizontal distance at which a known object can be seen.

  219. Visibility - midnight

    Visibility at local midnight. Minimal horizontal distance at which a known object can be seen.

  220. Visibility at 1.5m

    0-19-0

    Distance at which a known object can be seen horizontally from screen level (1.5m).

  221. Wet bulb potential temperature at 500hPa

    0-0-192 (local)

    Wet bulb potential temperature (temperature that a parcel of air at any level would have if starting at the wet bulb temperature, it were brought at a saturated adiabatic lapse rate, to the standard pressure of 1000hPa) on pressure levels

  222. Wet bulb potential temperature at 700hPa

    0-0-192 (local)

    Wet bulb potential temperature (temperature that a parcel of air at any level would have if starting at the wet bulb temperature, it were brought at a saturated adiabatic lapse rate, to the standard pressure of 1000hPa) on pressure levels

  223. Wet bulb potential temperature at 850hPa

    0-0-192 (local)

    Wet bulb potential temperature (temperature that a parcel of air at any level would have if starting at the wet bulb temperature, it were brought at a saturated adiabatic lapse rate, to the standard pressure of 1000hPa) on pressure levels

  224. Wet bulb potential temperature at 925hPa

    0-0-192 (local)

    Wet bulb potential temperature (temperature that a parcel of air at any level would have if starting at the wet bulb temperature, it were brought at a saturated adiabatic lapse rate, to the standard pressure of 1000hPa) on pressure levels

  225. Wind direction

    0-2-0

    Wind on a height level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. In meteorological reports the direction of the wind vector is given as the direction from which it is blowing.

  226. Wind direction

    0-2-0

    Wind on a pressure level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. In meteorological reports the direction of the wind vector is given as the direction from which it is blowing.

  227. Wind direction at 10m

    Mean wind direction is equivalent to the mean direction observed over the 10 minutes preceding the validity time. In meteorological reports the direction of the wind vector is given as the direction from which it is blowing. 10m wind is the considered surface wind.

  228. Wind direction at 10m (surface adjusted)

    0-2-194 (local)

    Wind at 10m above the surface is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. In meteorological reports the direction of the wind vector is given as the direction from which it is blowing. NOTE: This with “wind speed at 10m” replaces “x wind at 10m” and “y wind at 10m”.

  229. Wind direction at 10m - midday

    Mean wind direction is equivalent to the mean direction observed over the 10 minutes preceding the validity time. In meteorological reports the direction of the wind vector is given as the direction from which it is blowing. 10m wind is the considered surface wind. Midday is local time.

  230. Wind direction at 10m - midnight

    Mean wind direction is equivalent to the mean direction observed over the 10 minutes preceding the validity time. In meteorological reports the direction of the wind vector is given as the direction from which it is blowing. 10m wind is the considered surface wind. Midnight is local time.

  231. Wind direction at maximum wind speed height

    0-2-0

    Wind direction (from which blowing) at level in the vertical where the maximum wind speed occurs.

  232. Wind gust speed at 10m

    The gust speed is equivalent to the maximum 3 second mean wind speed observed over the 10 minutes preceding the validity time. 10m wind is the considered surface wind.

  233. Wind gust speed at 10m - 1 hour maximum

    This can be considered as the extreme wind speed that might be experienced in this period

  234. Wind gust speed at 10m - 3 hour maximum

    This can be considered as the extreme wind speed that might be experienced in this period

  235. Wind speed

    0-2-1

    Wind on a pressure level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The speed is the magnitude of velocity.

  236. Wind speed

    0-2-1

    Wind on a height level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The speed is the magnitude of velocity.

  237. Wind speed at 10m

    Mean wind speed is equivalent to the mean speed observed over the 10 minutes preceding the validity time. 10m wind is the considered surface wind.

  238. Wind speed at 10m (surface adjusted)

    0-2-195 (local)

    Wind at 10m above the surface is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The speed is the magnitude of velocity. NOTE: This with “wind speed at 10m” replaces “x wind at 10m” and “y wind at 10m”.

  239. Wind speed at 10m (surface adjusted) - 1 hour maximum

    0-2-195 (local)

    Maximum diagnosed instantaneous wind speed at 10m in the previous hour. This can be considered as the extreme wind speed that might be experienced in this period

  240. Wind speed at 10m (surface adjusted) - 3 hour maximum

    0-2-195 (local)

    Implied depth of the layer of liquid water equivalent (LWE) snow produced by the model precipitation scheme which has been deposited on the surface in previous 3 hours. For the Global models (which run a convection scheme) the “snowfall accumulation from convection” must be added to this to get the total snowfall accumulation. (This is not required for the UK models as they do not run a convection scheme).

  241. Wind speed at 10m - midday

    Mean wind speed is equivalent to the mean speed observed over the 10 minutes preceding the validity time. 10m wind is the considered surface wind. Midday is local time.

  242. Wind speed at 10m - midnight

    Mean wind speed is equivalent to the mean speed observed over the 10 minutes preceding the validity time. 10m wind is the considered surface wind. Midnight is local time.

  243. Wind speed at maximum wind speed height

    0-2-1

    Wind speed at level in the vertical where the maximum wind speed occurs.

  244. Wind speed gust at 10m

    0-2-22

    Diagnosed instantaneous wind gust at 10m. This can be considered as the extreme rather than steady wind speed that might be experienced at this specific time.

  245. Wind speed gust at 10m - 1 hour maximum

    0-2-22

    Maximum diagnosed instantaneous wind gust at 10m in the previous hour. This can be considered as the extreme wind speed that might be experienced in this period.

  246. Wind speed gust at 10m - 3 hour maximum

    0-2-22

    Maximum diagnosed instantaneous wind gust at 10m in the previous three hours. This can be considered as the extreme wind speed that might be experienced in this period.

  247. Wind speed gust at 10m - 6 hour maximum

    0-2-22

    Maximum diagnosed instantaneous wind gust at 10m in the previous six hours. This can be considered as the extreme wind speed that might be experienced in this period.

  248. Wind speed gust at 10m - midday

    The gust speed is equivalent to the maximum 3 second mean wind speed observed over the 10 minutes preceding the validity time. 10m wind is the considered surface wind. Midday is local time.

  249. Wind speed gust at 10m - midnight

    The gust speed is equivalent to the maximum 3 second mean wind speed observed over the 10 minutes preceding the validity time. 10m wind is the considered surface wind. Midnight is local time.

  250. Wind u-component

    0-2-2

    Wind on a pressure level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The u component represents the horizontal speed of air moving towards the east.

  251. Wind u-component

    0-2-2

    Wind on a height level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The u component represents the horizontal speed of air moving towards the east.

  252. Wind u-component at 10m (surface adjusted)

    0-2-192 (local)

    Wind at 10m above the surface is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The u component represents the horizontal speed of air moving towards the east.

  253. Wind u-component at maximum wind speed height

    0-2-2

    Wind at maximum wind speed height above the surface is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The u component represents the horizontal speed of air moving towards the east.

  254. Wind v-component

    0-2-3

    Wind on a height level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The v component represents the horizontal speed of air moving towards the north.

  255. Wind v-component

    0-2-3

    Wind on a pressure level is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The v component represents the horizontal speed of air moving towards the north.

  256. Wind v-component at 10m (surface adjusted)

    0-2-193 (local)

    Wind at 10m above the surface is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The v component represents the horizontal speed of air moving towards the north.

  257. Wind v-component at maximum wind speed height

    0-2-3

    Wind at maximum wind speed height above the surface is defined as a two-dimensional (horizontal) air velocity vector with no vertical component. The v component represents the horizontal speed of air moving towards the north.