Right now
The most recent data we hold from NOAA arrived 7 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
8 other detections within 20 km in the last 24 hours, the nearest <1 km from here.
This alert expired on 16 May 2026 at 06:00 UTC. It is kept here as a record.
It is the 74th strongest of the 254 detections recorded within 20 km of this point since 10 March 2026. Another comparable one was recorded here earlier the same day. 5 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Watch issued May 15 at 10:05PM CDT until May 16 at 1:00AM CDT by NWS Sioux Falls SD
Urban PEI: 181,553 within a heuristic 50 km radius; not unique people.
Nearby, since 10 March 2026
- September 15, 2026 · score 55 · 0.0 km
- September 14, 2026 · score 55 · 0.0 km
- September 6, 2026 · score 37 · 0.0 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 43 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) | 43 / 100 |
| Legacy data-support index | 0.80/1 |
| Coordinates | 42.0000, -93.2000 |
| Nearest City | Marshalltown (25 km) |
| Urban exposure index (PEI) | 181.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-16T03:05:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Watch_noaa_urn:oid:2.49.0.1.840.0.3d540e9a879704f706f15351071ebee5 |
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: 2026-05-16T03:05:00.000Z.
First archived: 2026-05-16T03:07:12.600Z. 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 Watch |
| Urgency | Future |
| Certainty | Possible |
| AreaDesc | Ida, IA; Allamakee, IA; Chickasaw, IA; Clayton, IA; Fayette, IA; Floyd, IA; Howard, IA; Mitchell, IA; Winneshiek, IA; Fillmore, MN; Houston, MN; Winona, MN; Fremont, IA; Harrison, IA; Mills, IA; Monona, IA; Montgomery, IA; Page, IA; Pottawattamie, IA; Shelby, IA; Burt, NE; Butler, NE; Cass, NE; Dodge, NE; Douglas, NE; Lancaster, NE; Otoe, NE; Saline, NE; Sarpy, NE; Saunders, NE; Seward, NE; Washington, NE and 2 more areas |
| Headline | Severe Thunderstorm Watch issued May 15 at 10:05PM CDT until May 16 at 1:00AM CDT by NWS Sioux Falls SD |
| Expires | 2026-05-16T01:00:00-05:00 |
| SenderName | NWS Sioux Falls SD |
| HasExactCoords | false |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.3d540e9a879704f706f15351071ebee5e0578d96.002.1","noaa_urn:oid:2.49.0.1.840.0.3ca897e1a08ed19a111cb0476faf41c8f369ef7c.002.1","noaa_urn:oid:2.49.0.1.840.0.b863fe2b4358edf8bb9dd3985f6f20a74f522fa0.003.1","noaa_urn:oid:2.49.0.1.840.0.e8e133a4283d27e38cfc8f99fb3ce0aad533bede.001.1","noaa_urn:oid:2.49.0.1.840.0.e8e133a4283d27e38cfc8f99fb3ce0aad533bede.002.1"] |
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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