The short answer
Use SPC for preliminary storm reports and NCEI for historical event research. Keep product, dates, location and identifiers together; do not assume matching-looking entries are identical.
Two products, two purposes
SPC storm reports offer a preliminary view of reported severe weather. NCEI Storm Events provides a historical event archive. A recent preliminary report and a later archive entry should not be assumed to be identical records.
Inspect dates and coverage
Our preliminary page identifies its retrieval time and source. Our historical page states the archive year and coverage limit. Before searching for an event, make sure it falls inside that coverage. An event outside the loaded period cannot appear in the results.
An evidence worksheet
Record the product, event date, location, reported hail size and source identifier where available. Keep the product name beside any exported note. Differences can reflect the source process and coverage, so do not silently merge entries as if they were independent storms.
An empty result has limits
No matching record is not proof that hail did not occur. Reports depend on observation and reporting. Use the official source for further investigation and keep any property-specific evidence separate.
Your next steps
- Recent reports → inspect SPC preliminary data.
- Historical research → inspect NCEI coverage.
- Comparison → preserve dates and identifiers.
- No match → describe the search limits.
Common questions
Are SPC storm reports final?
No. SPC describes these as preliminary reports. Preserve their status when citing or comparing them with a later archive.
Why might I find no historical hail result?
First check our loaded period, location filter and source coverage. An empty search does not establish that no hail occurred.
Sources and editorial record
- SPC storm reports
- NCEI Storm Events Database
- SPC 30 June 2026 storm reports and time conventions
- NCEI 2026 Storm Events source file, 18 September version
Prepared with AI assistance from the linked sources. Independent human review pending. “Public Atlas Editorial” is a publication label. First edition: 2026-09-28. Scheduled source review: 2026-10-28. Data examples update with their source snapshots; the guide text is versioned separately.
Changes to this guide
- 2026-09-28 — First AI-assisted edition published with source links and review status disclosed.
- 2026-09-28 — Added dated SPC and NCEI Independence examples, original time fields and archive-version timeline.
- 2026-09-29 — Added focused reader questions and concise answers with source links; checked primary-source guidance and retained pending human review.