Information About the National Water Model

Output File Contents

Content of output files varies by forecast configuration (internal variable names and units are given in parenthesis). Several channel outputs have separate open loop companion configuration, labeled "no_da", which is the same as the respective normal configuration but does not have assimilation data applied. The configurations that have "no_da" counterparts are indicated in the body of this document. Select a forecast configuration and file type to view related variable definitions and names. All data files are NetCDF4 file format.

Table of Contents

All Configurations
Analysis Assimilation
Analysis Assimilation Extended
Analysis Assimilation Long Range
Short Range Forecast
Medium Range Forecast
Long Range Forecast
Forcing 1km grid files

All Configurations

250m terrain grid files
(Not available for Analysis Assimilation Long Range and Long Range Forecast configurations)
  • Ponded water depth (sfcheadsubrt, mm)
  • Water table depth (zwattablrt, m)
Reservoir point files
(Available for all configurations)
  • Lake inflow (inflow, m3 s-1)
  • Lake outflow (outflow, m3 s-1)
  • Reservoir assimilated value (reservoir_assimiated_value, m3 s-1)
  • Water surface elevation (water_sfc_elev, m)
Total water level files
(Available for all configurations)
  • Elevation (sea surface elevation relative to NAVD88 for Atlantic/Gulf and Pacific domains, sea surface elevation relative to LMSL for Hawaii and Puerto Rico domains, m for NetCDF files and feet for SHEF files)

Analysis Assimilation

CONUS channel point files
("no_da" version available. * variable not included in "no_da" configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3) *
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
CONUS 1km land grid files
  • Accumulated meltwater from bottom snow layer (ACSNOM, mm)
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Evaporation rate from soil (EDIR, kg m-2 s-1)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Number of snow layers (ISNOW, count)
  • Rainfall rate on the ground (QRAIN, mm s-1)
  • Snow-cover fraction on the ground (FSNO, 1)
  • Snow depth (SNOWH, m)
  • Snow layer liquid water (SNLIQ, mm)
  • Snow water equivalent (SNEQV, kg m-2)
  • Snowfall rate on the ground (QSNOW, mm s-1)
  • Soil temperature (SOIL_T, K)
  • Volumetric soil moisture, the dimensionless ratio of water volume (m3) to soil volume (m3) (SOIL_M, m3 m-3)
Hawaii channel point files
("no_da" version available. * variable not included in "no_da" configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3)*
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
Hawaii 1km land grid files
  • Accumulated meltwater from bottom snow layer (ACSNOM, mm)
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Evaporation rate from soil (EDIR, kg m-2 s-1)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Evaporation rate from soil (EDIR, kg m-2 s-1)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Number of snow layers (ISNOW, count)
  • Rainfall rate on the ground (QRAIN, mm s-1)
  • Snow-cover fraction on the ground (FSNO, 1)
  • Snow depth (SNOWH, m)
  • Snow layer liquid water (SNLIQ, mm)
  • Snow water equivalent (SNEQV, kg m-2)
  • Snowfall rate on the ground (QSNOW, mm s-1)
  • Soil temperature (SOIL_T, K)
  • Volumetric soil moisture, the dimensionless ratio of water volume (m3) to soil volume (m3) (SOIL_M, m3 m-3)
Puerto Rico / US Virgin Islands channel point files
("no_da" version available. * variable not included in "no_da" configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3) *
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
Puerto Rico / US Virgin Islands 1km land grid files
  • Accumulated meltwater from bottom snow layer (ACSNOM, mm)
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Evaporation rate from soil (EDIR, kg m-2 s-1)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Number of snow layers (ISNOW, count)
  • Rainfall rate on the ground (QRAIN, mm s-1)
  • Snow-cover fraction on the ground (FSNO, 1)
  • Snow depth (SNOWH, m)
  • Snow layer liquid water (SNLIQ, mm)
  • Snow water equivalent (SNEQV, kg m-2)
  • Snowfall rate on the ground (QSNOW, mm s-1)
  • Soil temperature (SOIL_T, K)
  • Volumetric soil moisture, the dimensionless ratio of water volume (m3) to soil volume (m3) (SOIL_M, m3 m-3)

Analysis Assimilation Extended

CONUS channel point files
("no_da" version available. * variable not included in "no_da" configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3) *
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
CONUS 1km land grid files
  • Accumulated meltwater from bottom snow layer (ACSNOM, mm)
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Evaporation rate from soil (EDIR, kg m-2 s-1)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Number of snow layers (ISNOW, count)
  • Rainfall rate on the ground (QRAIN, mm s-1)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Snow-cover fraction on the ground (FSNO, 1)
  • Snow depth (SNOWH, m)
  • Snow layer liquid water (SNLIQ, mm)
  • Snow water equivalent (SNEQV, kg m-2)
  • Snowfall rate on the ground (QSNOW, mm s-1)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Soil temperature (SOIL_T, K)
  • Volumetric soil moisture, the dimensionless ratio of water volume (m3) to soil volume (m3) (SOIL_M, m3 m-3)

Analysis Assimilation Long Range

CONUS channel point files
("no_da" version available. * variable not included in "no_da configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3) *
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
CONUS 1km land grid files
  • Accumulated meltwater from bottom snow layer (ACSNOM, mm)
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Evaporation rate from soil (EDIR, kg m-2 s-1)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Number of snow layers (ISNOW, count)
  • Rainfall rate on the ground (QRAIN, mm s-1)
  • Snow-cover fraction on the ground (FSNO, 1)
  • Snow depth (SNOWH, m)
  • Snow layer liquid water (SNLIQ, mm)
  • Snow water equivalent (SNEQV, kg m-2)
  • Snowfall rate on the ground (QSNOW, mm s-1)
  • Soil temperature (SOIL_T, K)
  • Volumetric soil moisture, the dimensionless ratio of water volume (m3) to soil volume (m3) (SOIL_M, m3 m-3)

Short Range Forecast

CONUS channel point files
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3)
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
CONUS 1km land grid files
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Snow-cover fraction on the ground (FSNO, 1)
  • Snow depth (SNOWH, m)
  • Snow water equivalent (SNEQV, kg m-2)
Hawaii channel point files
("no_da" version available. * variable not included in "no_da" configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3) *
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
Hawaii 1km land grid files
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Snow depth (SNOWH, m)
  • Snow water equivalent (SNEQV, kg m-2)
  • Snow-cover fraction on the ground (FSNO, 1)
Puerto Rico / US Virgin Islands channel point files
("no_da" version available. * variable not included in "no_da" configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3) *
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
Puerto Rico / US Virgin Islands 1km land grid files
  • Accumulated total evapotranspiration (ACCET, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Snow depth (SNOWH, m)
  • Snow water equivalent (SNEQV, kg m-2)
  • Snow-cover fraction on the ground (FSNO, 1)

Medium Range Forecast

CONUS channel point files
("no_da" version available. * variable not included in "no_da" configuration)
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Flux from gw bucket (qBucket, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
  • Runoff from bottom of soil to bucket (qBtmVertRunoff, m3) *
  • Runoff from terrain routing (qSfcLatRunoff, m3 s-1)
CONUS 1km land grid files
  • Accumulated canopy evaporation (ACCECAN, mm)
  • Accumulated direct soil evaporation (ACCEDIR, mm)
  • Accumulated melting water out of snow bottom (ACSNOM, mm)
  • Accumulated total evapotranspiration (ACCET, mm)
  • Accumulated transpiration (ACCETRAN, mm)
  • Accumulated underground runoff (UGDRNOFF, mm)
  • Average snow temperature (by layer mass) (SNOWT_AVG, K)
  • Fraction of soil moisture that is ice (SOILICE, 1)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Heat flux into the soil (GRDFLX, W m-2)
  • Number of snow layers (ISNOW, count)
  • Snow-cover fraction on the ground (FSNO, 1)
  • Snow depth (SNOWH, m)
  • Snow layer liquid water (SNLIQ, mm)
  • Snow water equivalent (SNEQV, kg m-2)
  • Soil temperature (SOIL_T, K)
  • Surface radiative temperature (TRAD, K)
  • Total absorbed SW radiation (FSA, W m-2)
  • Total canopy water (liquid + ice) (CANWAT, mm)
  • Total latent heat to the atmosphere (LH, W m-2)
  • Total net LW radiation to atmosphere (FIRA, W m-2)
  • Total sensible heat to the atmosphere (HFX, W m-2)
  • Volumetric soil moisture, the dimensionless ratio of water volume (m3) to soil volume (m3) (SOIL_M, m3 m-3)

Long Range Forecast

CONUS channel point files
  • Amount of stream flow alteration from assimilation (nudge, m3 s-1)
  • Stream flow (streamflow, m3 s-1)
  • Stream velocity (velocity, m s-1)
CONUS 1km land grid files
  • Accumulated melting water out of snow bottom (ACSNOM, mm)
  • Accumulated surface runoff (SFCRNOFF, mm)
  • Accumulated total evapotranspiration (ACCET, mm)
  • Accumulated underground runoff (UGDRNOFF, mm)
  • Fraction of soil saturation, column integrated (SOILSAT, 1)
  • Fraction of soil saturation, top 2 layers, 0.4m depth (SOILSAT_TOP, 1)
  • Snow water equivalent (SNEQV, kg m-2)
  • Total canopy water (liquid + ice) (CANWAT, mm)

Forcing Data

All of the preceding analysis and forecast configurations require the same set of 1km forcing variables: precipitation rate, surface pressure, shortwave radiation, longwave radiation, u-wind, v-wind, temperature, and specific humidity, but, as mentioned on the NWM About Page, these fields come from different sources for each model configuration.

Forcing 1km grid files
(Not available for Analysis Assimilation Long Range and Long Range Forecast configurations)
  • 10m U-component of wind (U2D, m s-1)
  • 10m V-component of wind (V2D, m s-1)
  • 2m Air Temperature (T2D, K)
  • 2m Specific Humidity, dimensionless ratio of the mass of water vapor (kg) to the total mass of the system (kg) (Q2D, kg kg-1)
  • Surface downward long-wave radiation flux (LWDOWN, W m-2)
  • Surface downward short-wave radiation flux (SWDOWN, W m-2)
  • Surface Precipitation Rate (RAINRATE, mm s-1)
  • Surface Pressure (PSFC, Pa)