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.
Colors:TornHailWind
Sources to Fetch
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SPC Outlooks
What's this?
SPC updates the Day 1 outlook multiple times per day. Each update can upgrade or downgrade risk levels as weather develops.
Highest Risk — Checks ALL updates for each day and shows only the one with the highest peak risk. Best for seeing the worst-case scenario. 2000Z — Late afternoon update (~3pm CT). Catches upgrades based on actual storm development. 1630Z — The main outlook (~11:30am CT). Most detailed and commonly referenced. 1300Z — Morning update (~8am CT). 1200Z — First outlook of the day (~7am CT). Often the most conservative. 0100Z — Overnight update (~8pm CT previous evening) for the remaining threat.
Day 1 categorical outlook for each day in date range. Toggle categories in Layers panel.