Right now
The most recent data we hold from NOAA arrived 3 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 23:15 UTC. It is kept here as a record.
It is the 10th strongest of the 32 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 7 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 20 at 5:44PM CDT until July 20 at 6:15PM CDT by NWS Des Moines IA
Urban PEI: 42,745 within a heuristic 50 km radius; not unique people.
Nearby, since 16 March 2026
- July 6, 2026 · score 34 · 14.4 km
- May 19, 2026 · score 58 · 21.6 km
- June 10, 2026 · score 43 · 23.5 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 28 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) | 28 / 100 |
| Legacy data-support index | 0.80/1 |
| Coordinates | 42.0513, -92.6904 |
| Nearest City | Marshalltown (18 km) |
| Urban exposure index (PEI) | 42.7K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-20T22:44:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.f33f480e3825fecda45fa6f481368c98 |
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: 2026-07-20T22:44:00.000Z.
First archived: 2026-07-20T22:48:27.310Z. 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 | Grundy, IA; Hardin, IA; Marshall, IA; Story, IA; Benton, IA; Cedar, IA; Iowa, IA; Johnson, IA; Jones, IA; Linn, IA; Muscatine, IA |
| Headline | Severe Thunderstorm Warning issued July 20 at 5:44PM CDT until July 20 at 6:15PM CDT by NWS Des Moines IA |
| Expires | 2026-07-20T18:15:00-05:00 |
| SenderName | NWS Des Moines IA |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.f33f480e3825fecda45fa6f481368c98791ebc9b.001.1","noaa_urn:oid:2.49.0.1.840.0.1703bed71da69464d042e52586c4c4b5b7b1f280.001.1","noaa_urn:oid:2.49.0.1.840.0.bdbf9b04979da2bd4b3e5595b1e5bafefd1b4ccc.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.
Review the area, threshold and delivery channel in your account.
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