This alert expired on 20 May 2026 at 22:15 UTC. It is kept here as a record.
No stronger detection stands among the 420 recorded within 20 km of this point since 12 March 2026 — 261 others scored the same. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 20 at 5:47PM EDT until May 20 at 6:15PM EDT by NWS Upton NY
An estimated 3,712,588 people live within 50 km of this point.
Nearby, since 12 March 2026
- August 3, 2026 · score 52 · 1.8 km
- June 22, 2026 · score 52 · 2.7 km
- July 27, 2026 · score 52 · 3.0 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 52 out of 100, at 79 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 52 / 100 |
| Our confidence | 79% |
| Coordinates | 40.0427, -75.1193 |
| Nearest City | Olney (0 km) |
| Population Exposed | 3.7M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T21:47:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Fairfield, CT; Westchester, NY; Burlington, NJ; Hunterdon, NJ; Mercer, NJ; Somerset, NJ; Bucks, PA; Montgomery, PA; Philadelphia, PA; Hunterdon, NJ; Middlesex, NJ; Morris, NJ; Somerset, NJ; Warren, NJ and 6 more areas |
| Headline | Severe Thunderstorm Warning issued May 20 at 5:47PM EDT until May 20 at 6:15PM EDT by NWS Upton NY |
| Expires | 2026-05-20T18:15:00-04:00 |
| SenderName | NWS Upton NY |
| HasExactCoords | true |
| MergedCount | 9 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.24b8461e194fe6f32814b0c260e899ee71a7547d.001.1","noaa_urn:oid:2.49.0.1.840.0.2fdade584f31ea4203731482142ea36c6ae5cd55.002.1","noaa_urn:oid:2.49.0.1.840.0.f125f3f2eec65d5a8ffc50003da44daf911134e8.002.1","noaa_urn:oid:2.49.0.1.840.0.03ca2d190fbe860996183302a8034e96194dcd54.001.1","noaa_urn:oid:2.49.0.1.840.0.3a9a720f13f0650d3faa5fad38ae28ac92c2cde7.001.1","noaa_urn:oid:2.49.0.1.840.0.17179e4b9b5dafc2f0ed37701045b41e1ef0a7b7.001.1","noaa_urn:oid:2.49.0.1.840.0.fe508ac293398ad240466709cc560c926f8ccaa3.001.1","noaa_urn:oid:2.49.0.1.840.0.769b014eafcd4f80ea87246012a3bda6c57f8b7c.001.1","noaa_urn:oid:2.49.0.1.840.0.add74f0042af4b0db11f1149a47be98019241dbc.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 10 February 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.
Calamity.live data shows a weather event with CalamityScore 52/100, near Olney (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 194 scientific monitoring sources.