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. All NetCDF data files are NetCDF4 file format.

NWM Channel, Land, Reservoir and Terrain Output Type Files Analysis Assimilation (All Domains)

Channel point files

("no_da" version available for all domains. * 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)

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)

Reservoir point files

Lake inflow (inflow, m3 s-1)
Lake outflow (outflow, m3 s-1)
Reservoir assimilated value (reservoir_assimilated_value, m3 s-1)
Water surface elevation (water_sfc_elev, m)

250m (CONUS and Alaska) and 100m (Hawaii and Puerto Rico / USVI) terrain grid files

Ponded water depth (sfcheadsubrt, mm)
Water table depth (zwattablrt, m)

Analysis Assimilation Extended (CONUS and Alaska Domains)

Channel point files

("no_da" version available for CONUS and Alaska domains. * 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)

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)
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)

Reservoir point files

Lake inflow (inflow, m3 s-1)
Lake outflow (outflow, m3 s-1)
Reservoir assimilated value (reservoir_assimilated_value, m3 s-1)
Water surface elevation (water_sfc_elev, m)

250m terrain grid files

Ponded water depth (sfcheadsubrt, mm)
Water table depth (zwattablrt, m)

Analysis Assimilation Long Range (CONUS)

Channel point files

("no_da" version available for CONUS domain. * 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)

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)

Reservoir point files

Lake inflow (inflow, m3 s-1)
Lake outflow (outflow, m3 s-1)
Reservoir assimilated value (reservoir_assimilated_value, m3 s-1)
Water surface elevation (water_sfc_elev, m)

Short Range Forecast (All Domains)

Channel point files

("no_da" version available for Hawaii and Puerto Rico / USVI domains. * 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)

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)

Reservoir point files

Lake inflow (inflow, m3 s-1)
Lake outflow (outflow, m3 s-1)
Reservoir assimilated value (reservoir_assimilated_value, m3 s-1)
Water surface elevation (water_sfc_elev, m)

250m (CONUS and Alaska) and 100m (Hawaii and Puerto Rico / USVI) terrain grid files

Ponded water depth (sfcheadsubrt, mm)
Water table depth (zwattablrt, m)

Medium Range Forecast (CONUS and Alaska)

Channel point files

("no_da" version available for CONUS and Alaska domains. * 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)

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)

Reservoir point files

Lake inflow (inflow, m3 s-1)
Lake outflow (outflow, m3 s-1)
Reservoir assimilated value (reservoir_assimilated_value, m3 s-1)
Water surface elevation (water_sfc_elev, m)

250m terrain grid files

Ponded water depth (sfcheadsubrt, mm)
Water table depth (zwattablrt, m)

Long Range Forecast (CONUS and Alaska)

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)

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)

Reservoir point files

Lake inflow (inflow, m3 s-1)
Lake outflow (outflow, m3 s-1)
Reservoir assimilated value (reservoir_assimilated_value, m3 s-1)
Water surface elevation (water_sfc_elev, m)

NWM Total Water Level Output Files (CONUS Atlantic/Gulf, CONUS Pacific, Hawaii, and Puerto Rico / USVI Domains)

Total water level files

(Available for all TWL 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)

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)

Office of Water Prediction Locations

Alabama - National Water Center
205 Hackberry Lane
Tuscaloosa, AL 35401

Maryland
1325 East West Highway
Silver Spring, MD 20910

Minnesota
1735 Lake Drive W.
Chanhassen, MN 55317