Data Sources

The public weather data StormAuditor uses, what each source is best for, and the limitations you should keep in mind.

Primary gridded and radar sources

NOAA MRMS MESH (Multi-Radar Multi-Sensor, Maximum Estimated Size of Hail) provides radar-derived hail size estimates on a roughly 1-km grid — the backbone of the Hail Explorer and hail history products. NOAA URMA/RTMA (the NWS analysis of record) provides hourly gridded wind analysis at 2.5-km resolution, and HRRR model fields supplement recent dates. These grids are analyses and estimates, not point measurements.

Observations and reports

ASOS/AWOS station observations supply measured wind gusts from airport-grade instruments. NWS Local Storm Reports (LSRs) capture spotter, public, and emergency-management reports of hail and wind. NWS warnings (severe thunderstorm, tornado) document what forecasters warned in real time. NCEI Storm Events is the official post-storm record, and FEMA declarations mark federally recognized disasters.

How sources are combined

Address-level wind estimates blend the URMA background with station gusts and measured storm reports under the SAWE-2 wind methodology. Hail values combine MESH with warnings and reports under the SAHE-2 hail methodology. State pages fuse warnings, reports, NCEI records, and FEMA declarations into deduplicated per-state event streams.

Update cadence and limitations

Most layers update continuously or daily as NOAA publishes them; official NCEI records trail real time by weeks to months. Every source has resolution and coverage limits — read Limitations and Data Disclaimers before relying on any single value, and see the data license for how the aggregated datasets may be reused and cited.