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SPC storm reports vs. NCEI Storm Events: which to cite, when

NOAA gives the public two views of severe weather. The Storm Prediction Center publishes preliminary local storm reports the same day — raw spotter and office relays, in UTC "convective days," subject to correction. The NCEI Storm Events Database is the official record: forecast offices quality-control, deduplicate and narrate events, and NCEI compiles them into yearly files re-issued as corrections land (typically a few months behind).

For a storm last week, SPC is all there is — cite it as preliminary. For a storm last year, Storm Events is the citation; the SPC row that preceded it was its draft. A defensible report keeps both, labels every row's provenance, and stamps the compile vintage of the Storm Events file it used, because the file itself gets re-issued.

Why do SPC counts and Storm Events counts differ for the same storm?

SPC reports are preliminary one-line relays; offices later merge duplicates, adjust magnitudes, add events that arrived after the convective day closed, and write narratives. The compiled Storm Events entry is the official version. Differences are normal and expected — which is why provenance labels matter.

Which one should an insurance dispute cite?

Storm Events, when the event date is old enough to be compiled (it carries event IDs, narratives, and supports NCEI certification). SPC preliminary reports are appropriate for recent dates, clearly labeled preliminary, and superseded once the official entry exists.

What does the "vintage" of a Storm Events file mean?

NCEI re-compiles yearly files as corrections arrive — the filename carries the compile date. Two people can pull "2025 hail" and get different rows if they pulled different vintages. Stamping the vintage on every page and report makes the evidence reproducible.

Sources and standing caveat

Official records referenced throughout: NCEI Storm Events Database (the official NWS storm record, 1950–present) and SPC daily storm reports (preliminary, same-day). NWS records are point and path observations. The absence of a nearby report does NOT prove that no hail fell at this address — it means no observation was logged nearby. A report of nearby hail documents the event; it does not by itself prove damage to a specific structure. Nothing on this page is legal, insurance, or public-adjusting advice — deadlines, coverage and remedies are policy- and state-specific.

Put the record in the file

A per-address verification report compiles every NWS-recorded hail and wind event within 1, 3 and 10 miles of any US address — distances, official narratives, citations, provenance labels — formatted as an insurance-appeal attachment, hosted on HailEvidence (the neutral evidence surface).

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