Right now
The most recent data we hold from NOAA arrived 2 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 20 July 2026 at 01:22 UTC. It is kept here as a record.
It is the 7th strongest of the 48 detections recorded within 20 km of this point since 15 March 2026. Another comparable one was recorded here earlier the same day. 8 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 19 at 8:12PM CDT until July 19 at 8:15PM CDT by NWS Aberdeen SD
Nearby, since 15 March 2026
- June 4, 2026 · score 46 · 11.3 km
- July 19, 2026 · score 22 · 24.6 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 22 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 22 / 100 |
| Legacy data-support index | 0.60/1 |
| Coordinates | 43.5540, -99.5222 |
| Nearest City | Mitchell (121 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Date | 2026-07-20 — time not reported by the source |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.294b9ad970ee68d4e3d55c76fb706c1c |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-07-20 — time not reported.
First archived: 2026-07-20T01:13:29.856Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Lyman, SD; Tripp, SD; Gregory, SD |
| Headline | Severe Thunderstorm Warning issued July 19 at 8:12PM CDT until July 19 at 8:15PM CDT by NWS Aberdeen SD |
| Expires | 2026-07-19T20:22:00-05:00 |
| SenderName | NWS Aberdeen SD |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.294b9ad970ee68d4e3d55c76fb706c1c9c20c699.001.1","noaa_urn:oid:2.49.0.1.840.0.4be3c334c28fe322ae8246f814e19206e0fa64ee.001.1","noaa_urn:oid:2.49.0.1.840.0.23c114725fb0f28b9bb37091f8d17a7d96a4a6f7.001.1"] |
Safety Information
Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.
Series begins 8 March 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
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