Convective Day (12Z–12Z) — The NWS/SPC standard "severe weather day." Runs from 12:00 UTC (noon) on the selected date to 12:00 UTC the next day. This captures the full afternoon-through-overnight severe window.
Calendar Day (00Z–24Z) — Exact midnight-to-midnight UTC. Useful for matching raw calendar boundaries.
Custom — Set your own start and end times in UTC.
Start Time (ET)
End Time (ET)
Warning Types to Fetch
Storm Reports
What's the difference?
IEM LSR vs SPC Reports
IEM LSR — Raw Local Storm Reports from NWS offices. Real-time. May include duplicates (multiple reports per event from spotters, radar, surveys). Best for same-day events.
SPC Filtered — Post-processed by SPC staff. De-duplicated, one entry per event. Best for clean counts and historical analysis. Typically available next day.
SPC Unfiltered — All raw reports archived by SPC. Same as IEM LSR but from SPC's archive. Useful when IEM LSR isn't available.
Tip: Use IEM LSR for live events, SPC Filtered for next-day and historical review.