This alert expired on 21 July 2026 at 21:45 UTC. It is kept here as a record.
It is the 157th strongest of the 251 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day. 9 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 21 at 5:02PM EDT until July 21 at 5:45PM EDT by NWS Mount Holly NJ
An estimated 3,341,355 people live within 50 km of this point.
Nearby, since 12 March 2026
- July 28, 2026 · score 76 · 1.9 km
- July 27, 2026 · score 52 · 3.1 km
- August 27, 2026 · score 52 · 4.0 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 46 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) | 46 / 100 |
| Our confidence | 79% |
| Coordinates | 39.7933, -75.4642 |
| Nearest City | Wilmington (9 km) |
| Population Exposed | 3.3M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-21T21:02:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Middlesex, NJ; Monmouth, NJ; Somerset, NJ; Delaware, PA; Montgomery, PA; Philadelphia, PA; New Castle, DE; Gloucester, NJ; Salem, NJ; Chester, PA; Delaware, PA and 1 more areas |
| Headline | Severe Thunderstorm Warning issued July 21 at 5:02PM EDT until July 21 at 5:45PM EDT by NWS Mount Holly NJ |
| Expires | 2026-07-21T17:45:00-04:00 |
| SenderName | NWS Mount Holly NJ |
| HasExactCoords | true |
| MergedCount | 4 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.ba7207d20e4bfed0e624b2e74dcf0b590ca06d83.002.1","noaa_urn:oid:2.49.0.1.840.0.569fd7ad5c705c2a096bc7de34dc41860eb4aa77.002.1","noaa_urn:oid:2.49.0.1.840.0.9559ba3918892896bba700fcd29e3a3e40ae9a27.001.1","noaa_urn:oid:2.49.0.1.840.0.032ebe63d7d212d2d6abc1952405e7f875f5fdbb.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 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 46/100, near Wilmington (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.