Catalog > NOAA HRRR > NOAA HRRR forecast, 48 hour

NOAA HRRR forecast, 48 hour

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Spatial domain	Continental United States
Spatial resolution	3km
Time domain	Forecasts initialized 2018-07-13 12:00:00 UTC to Present
Time resolution	Forecasts initialized every 6 hours.
Forecast domain	Forecast lead time 0-48 hours ahead
Forecast resolution	Hourly

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The High-Resolution Rapid Refresh (HRRR) is a NOAA real-time 3-km resolution, hourly updated, cloud-resolving, convection-allowing atmospheric model, initialized by 3km grids with 3km radar assimilation. Radar data is assimilated in the HRRR every 15 min over a 1-h period adding further detail to that provided by the hourly data assimilation from the 13km radar-enhanced Rapid Refresh.

This dataset is an archive of past and present HRRR forecasts. Forecasts are identified by an initialization time (init_time) denoting the start time of the model run. Each forecast has an hourly forecast step along the lead_time dimension. This dataset contains only the 00, 06, 12, and 18 hour UTC initialization times which produce the full length, 48 hour forecast.

This dataset uses the native HRRR Lambert Conformal Conic projection, with spatial indexing along the x and y dimensions. The example notebook shows how to use the embedded spatial reference to select geographic areas of interest.

Examples

	Open notebook in github
	Open notebook in colab

dynamical.org - NOAA HRRR forecast, 48 hour

Maximum temperature in a forecast

import xarray as xr  # xarray>=2025.1.2 and zarr>=3.0.8 for zarr v3 support

ds = xr.open_zarr("https://data.dynamical.org/noaa/hrrr/forecast-48-hour/[email protected]")
ds["temperature_2m"].sel(init_time="2025-01-01T00", x=0, y=0, method="nearest").max().compute()

Dimensions

	min	max	units
init_time	2018-07-13T12:00:00	Present	seconds since 1970-01-01

lead_time	0 days 00:00:00	2 days 00:00:00	seconds

x	-2700000	2700000	m

y	-1600000	1600000	m

Variables

	units	dimensions
categorical_freezing_rain_surface Categorical freezing rain	0=no; 1=yes	init_time × lead_time × y × x

categorical_ice_pellets_surface Categorical ice pellets	0=no; 1=yes	init_time × lead_time × y × x

categorical_rain_surface Categorical rain	0=no; 1=yes	init_time × lead_time × y × x

categorical_snow_surface Categorical snow	0=no; 1=yes	init_time × lead_time × y × x

composite_reflectivity Composite reflectivity	dBZ	init_time × lead_time × y × x

downward_long_wave_radiation_flux_surface Surface downward long-wave radiation flux	W/(m^2)	init_time × lead_time × y × x

downward_short_wave_radiation_flux_surface Surface downward short-wave radiation flux	W/(m^2)	init_time × lead_time × y × x

expected_forecast_length	seconds	init_time

geopotential_height_cloud_ceiling Geopotential height	gpm	init_time × lead_time × y × x

ingested_forecast_length	seconds	init_time

latitude	degrees_north	y × x

longitude	degrees_east	y × x

percent_frozen_precipitation_surface Percent frozen precipitation	%	init_time × lead_time × y × x

precipitable_water_atmosphere Precipitable water	kg/(m^2)	init_time × lead_time × y × x

precipitation_surface Total Precipitation Average precipitation rate since the previous forecast step.	mm/s	init_time × lead_time × y × x

pressure_reduced_to_mean_sea_level Pressure reduced to MSL	Pa	init_time × lead_time × y × x

pressure_surface Surface pressure	Pa	init_time × lead_time × y × x

relative_humidity_2m 2 metre relative humidity	%	init_time × lead_time × y × x

temperature_2m 2 metre temperature	C	init_time × lead_time × y × x

total_cloud_cover_atmosphere Total Cloud Cover	%	init_time × lead_time × y × x

valid_time	seconds since 1970-01-01	init_time × lead_time

wind_u_10m 10 metre U wind component	m/s	init_time × lead_time × y × x

wind_u_80m U-component of wind (80 m above ground)	m/s	init_time × lead_time × y × x

wind_v_10m 10 metre V wind component	m/s	init_time × lead_time × y × x

wind_v_80m V-component of wind (80 m above ground)	m/s	init_time × lead_time × y × x

Don't see what you're looking for? Let us know at [email protected].

Details

Sources

The source grib files this archive is contructed from are provided by NOAA Open Data Dissemniation (NODD) and accessed from the AWS Open Data Registry.

Data availability

Forecasts initialized through 2020-12-02T06 UTC include data only for the first 36 hours; steps 37–48 are filled with NaNs. Starting with the 2020-12-02T12 UTC initialization, forecasts cover the full 48 hours.

Storage

Storage for this dataset is generously provided by Source Cooperative, a Radiant Earth initiative.

Compression

The data values in this dataset have been rounded in their binary floating point representation to improve compression. See Klöwer et al. 2021 for more information on this approach. The exact number of rounded bits can be found in our reformatting code.