This alert expired on 1 September 2026 at 22:30 UTC. It is kept here as a record.
It is the 7th strongest of the 31 detections recorded within 20 km of this point since 17 March 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 1 at 5:45PM EDT until September 1 at 6:30PM EDT by NWS Mount Holly NJ
An estimated 29,201 people live within 50 km of this point.
Nearby, since 17 March 2026
- August 2, 2026 · score 34 · 7.3 km
- June 12, 2026 · score 32 · 24.3 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, at 80 % 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) | 28 / 100 |
| Our confidence | 80% |
| Coordinates | 41.4052, -76.7142 |
| Nearest City | Williamsport (30 km) |
| Population Exposed | 29.2K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-01T21:45:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.b50800ab5055e839c8bf56340479547835a4074a.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Warren, NJ; Monroe, PA; Northampton, PA; Lycoming, PA; Potter, PA; Tioga, PA; Columbia, PA; Lycoming, PA; Montour, PA; Northumberland, PA and 1 more areas |
| Headline | Severe Thunderstorm Warning issued September 1 at 5:45PM EDT until September 1 at 6:30PM EDT by NWS Mount Holly NJ |
| Expires | 2026-09-01T18:30:00-04:00 |
| SenderName | NWS Mount Holly NJ |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.b50800ab5055e839c8bf56340479547835a4074a.001.1","noaa_urn:oid:2.49.0.1.840.0.aaa744400c8594adfa22b71729a15244ab036eeb.001.1","noaa_urn:oid:2.49.0.1.840.0.dd21d5f14878d45b39a9ea932e085a04435f1994.001.1","noaa_urn:oid:2.49.0.1.840.0.986dfb4cd1fe3f8fecae576207527a497ce0be13.001.1","noaa_urn:oid:2.49.0.1.840.0.37914dc0bb5716564fbae89a6bc8fa81192935d7.001.1"] |
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.
Want to know when something happens near Williamsport?
Calamity.live data shows a weather event with CalamityScore 28/100, near Williamsport (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.