Right now
The most recent data we hold from NOAA arrived 4 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
2 other detections within 20 km in the last 24 hours, the nearest <1 km from here.
This alert expired on 19 May 2026 at 03:00 UTC. It is kept here as a record.
It is the 7th strongest of the 248 detections recorded within 20 km of this point since 10 March 2026. The last comparable one was on 18 May 2026. 50 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Tornado Watch issued May 18 at 7:44PM CDT until May 18 at 10:00PM CDT by NWS Omaha/Valley NE
Urban PEI: 181,553 within a heuristic 50 km radius; not unique people.
Nearby, since 10 March 2026
- September 14, 2026 · score 55 · 0.0 km
- September 6, 2026 · score 37 · 0.0 km
- September 2, 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 55 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 | High |
| Calamity Score (ours) | 55 / 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 | severe |
| Timestamp | 2026-05-19T00:44:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Tornado Watch_noaa_urn:oid:2.49.0.1.840.0.d2184b0efc4671f0853d6ece615e1e19 |
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: 2026-05-19T00:44:00.000Z.
First archived: 2026-05-19T00:50:14.150Z. 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 | Tornado Watch |
| Urgency | Future |
| Certainty | Possible |
| AreaDesc | Fremont, IA; Page, IA; Appanoose, IA; Lucas, IA; Monroe, IA; Wayne, IA; Adair, IA; Adams, IA; Cass, IA; Clarke, IA; Decatur, IA; Ringgold, IA; Taylor, IA; Union, IA |
| Headline | Tornado Watch issued May 18 at 7:44PM CDT until May 18 at 10:00PM CDT by NWS Omaha/Valley NE |
| Expires | 2026-05-18T22:00:00-05:00 |
| SenderName | NWS Omaha/Valley NE |
| HasExactCoords | false |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.d2184b0efc4671f0853d6ece615e1e197dfd996e.004.1","noaa_urn:oid:2.49.0.1.840.0.3e6433561301f6bb82c85a5e2c0213c09162b017.001.1","noaa_urn:oid:2.49.0.1.840.0.3e6433561301f6bb82c85a5e2c0213c09162b017.002.1"] |
Safety Information
If a tornado warning is issued: go to a basement or an interior room on the lowest floor, away from windows. A vehicle and a mobile home are not shelter. Cover your head and neck. Wait for the official all-clear before going outside, and watch for downed power lines and gas leaks afterwards.
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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