Methodology

How each StormAuditor tool produces its values — published openly so anyone can understand, question, and re-check our approach against the public weather record.

Every value, documented

StormAuditor publishes how each product derives its numbers so anyone can understand, question, and re-check the approach against the public weather record. The two core engines are SAWE-2 (wind) — URMA analysis-of-record background adjusted by measured station gusts and storm reports through a calibrated objective analysis — and SAHE-2 (hail) — the MRMS MESH radar value in the grid cell that contains the property, which a ground report within 1 mile can raise.

Also documented here

• How the Free Report Snapshot reaches its YES/NO (screening thresholds: wind ≥ 45 mph, hail ≥ 0.75 in. — deliberately below the NWS severe criteria of 58 mph and 1.00 in.).
• How date-of-loss candidate scoring organizes storm dates.
• How the Impact Heatmap shades counties and how state storm data deduplicates events.

Wind estimates are tested leave-one-station-out against held-back measurements, with statistics published on the wind page. Sources live on Data Sources; caveats on Limitations.

The aggregated datasets these methods produce are free to reuse under the data license, and any single estimate can be unpacked line by line with an Audit Report.

Primary source documentation

Every dataset StormAuditor uses is public and officially documented — verify any layer at the source:

• NWS MRMS documentation — the Multi-Radar Multi-Sensor system behind MESH radar-estimated hail size, with the algorithm lineage in Witt et al. (1998), Weather and Forecasting 13(2), doi:10.1175/1520-0434(1998)013<0286:AEHDAF>2.0.CO;2.
• NOAA NCEP RTMA/URMA products — the real-time and un-restricted mesoscale analyses that serve as the NWS analysis of record for surface wind.
• NOAA HRRR model — the High-Resolution Rapid Refresh fields that supplement recent dates.
• NWS ASOS program — the automated airport-grade surface observing network supplying measured gusts (with AWOS operated under FAA standards).
• SPC severe weather reports and NWS Local Storm Reports — spotter, public, and emergency-management reports of hail and wind.
• NCEI Storm Events Database — the official post-storm federal record.
• FEMA disaster declarations (Data.gov) — federal recognition of major events.