NOAA URMA analysis, virtual
| ID |
noaa-urma-analysis-virtual
|
| Spatial domain | Continental United States |
| Spatial resolution | 2.5 km |
| Time domain | 2017-05-02 00:00:00 UTC to Present |
| Time resolution | 1 hour |
STAC (browse) · validation report
The Unrestricted Mesoscale Analysis (URMA) is NOAA NCEP's hourly analysis of near-surface weather conditions, incorporating observations received after the RTMA analysis.
Hourly near-surface analyses incorporating observations received after RTMA, on the 2.5 km CONUS Western Expansion grid from 2017-05-02 onward. This virtual dataset references NOAA's GRIB files and is optimized for spatial (map) access. It contains 14 analysis fields, including significant wave height, with dimensions time, y, and x on the native Lambert Conformal Conic projection. Precipitation is not included.
Examples
|
RTMA, RTMA-RU and URMA analyses (Github) |
|
RTMA, RTMA-RU and URMA analyses (Colab) |
import dynamical_catalog # dynamical-catalog>=0.8.0
ds = dynamical_catalog.open("noaa-urma-analysis-virtual", chunks=None)
ds["temperature_2m"].sel(time="2025-01-01T00")import icechunk
import pystac
import xarray as xr
catalog = pystac.Catalog.from_file("https://stac.dynamical.org/catalog.json")
collection = catalog.get_child("noaa-urma-analysis-virtual")
asset = collection.assets["icechunk-https"]
authorize = icechunk.containers_credentials({"s3://noaa-urma-pds/": icechunk.s3_anonymous_credentials()})
repo = icechunk.Repository.open(
icechunk.http_storage(asset.href),
authorize_virtual_chunk_access=authorize,
)
session = repo.readonly_session("main")
ds = xr.open_zarr(session.store, chunks=None)
ds["temperature_2m"].sel(time="2025-01-01T00")Explore
Dimensions
| min | max | units | |
|---|---|---|---|
| time | 2017-05-02T00:00:00Z | Present | seconds since 1970-01-01 |
| x | -3271147.288 | 2681916.544 | m |
| y | -263797.503 | 3789568.485 | m |
Variables
Access a variable by its name (the bold identifier, e.g. ds["cloud_ceiling_height"]).
Dimensions: time × y × x
| variable | units |
|---|---|
cloud_ceiling_height
Ceiling (ceil)
|
m |
dew_point_temperature_2m
2 metre dewpoint temperature (2d)
|
degree_Celsius |
geopotential_height_surface
Geopotential height (gh)
|
m |
pressure_surface
Surface pressure (sp)
|
Pa |
significant_wave_height_surface
Significant height of combined wind waves and swell (swh)NaN where no wave analysis is made, such as over land and ice-covered water.
|
m |
specific_humidity_2m
Specific humidity (q)
|
1 |
temperature_2m
2 metre temperature (2t)
|
degree_Celsius |
total_cloud_cover_atmosphere
Total cloud cover (tcc)
|
percent |
visibility_surface
Visibility (vis)
|
m |
wind_direction_10m
10 metre wind direction (10wdir)Direction the wind blows from, clockwise from true north.
|
degree |
wind_gust_10m
Wind speed (gust) (gust)
|
m s-1 |
wind_speed_10m
10 metre wind speed (10si)
|
m s-1 |
wind_u_10m
10 metre U wind component (10u)Velocity along the model grid's x dimension, not eastward velocity.
|
m s-1 |
wind_v_10m
10 metre V wind component (10v)Velocity along the model grid's y dimension, not northward velocity.
|
m s-1 |
Details
License
Dataset licensed under CC BY 4.0.
Attribution and citation
NOAA NWS NCEP URMA data processed by dynamical.org from NOAA Open Data Dissemination archives.
Or NOAA URMA from dynamical.org.
Construction
Hourly URMA analyses incorporate observations received after RTMA. They are represented as virtual references to NOAA's CONUS Western Expansion GRIB files, on their native 2345 by 1597 Lambert Conformal Conic grid. Each chunk contains one complete field at one analysis time. The 14 fields include temperature, dew point, specific humidity, surface pressure, terrain height, wind, cloud cover, ceiling, visibility, and significant wave height. Precipitation is not included.
Wind components are grid-relative; wind direction is relative to true north. Ceiling and visibility retain the source's finite values. Their historical bounds vary, and ceiling's vertical reference is not established for this archive. Consult the validation report before interpreting these fields across eras.
Source
Source files are provided by NOAA Open Data Dissemination in the public NOAA URMA archive.
Data availability
The archive begins at 2017-05-02 00:00 UTC and updates hourly. Missing source files remain gaps. Significant wave height begins at 2018-12-03 12:00 UTC; earlier fields are excluded because they mix land zeros with calm-water zeros. Wave height is missing where no wave analysis is made, including land and ice-covered water. Great Lakes wave values begin at 2020-07-27 12:00 UTC. See the validation report for checked coverage, source-archive gaps, and historical field limitations.
Storage
Storage for this dataset is generously provided by AWS Open Data.
Chunks
This dataset is stored in Zarr format, which splits each variable into a grid of chunks — the smallest unit read from storage. When possible, aligning your reads with this dataset's chunk grid can significantly improve data access speed.
The element count and coordinate span of this dataset:
| dimension | chunk |
|---|---|
| time | 1 (1 hour) |
| y | 1597 (4055.91 km) |
| x | 2345 (5955.6 km) |
| uncompressed | 28.6 MiB |
Validation report
Review the validation report for variable availability, missing data, known quirks, fill values, value distributions, and sample plots.