This alert expired on 20 May 2026 at 18:32 UTC. It is kept here as a record.
No stronger detection stands among the 107 recorded within 20 km of this point since 16 March 2026 — 73 others scored the same. 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 Warning issued May 20 at 2:23PM EDT until May 20 at 2:30PM EDT by NWS State College PA
An estimated 164,372 people live within 50 km of this point.
Nearby, since 16 March 2026
- July 4, 2026 · score 43 · 3.4 km
- May 20, 2026 · score 43 · 6.0 km
- July 4, 2026 · score 43 · 6.1 km
How we know
Confirmed by 3 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 91 % 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) | 43 / 100 |
| Our confidence | 91% |
| Coordinates | 39.7783, -77.5400 |
| Nearest City | Chambersburg (21 km) |
| Population Exposed | 164.4K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T18:23:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.495112636e1bcd89fd62ef858f1588c46e6938dd.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Franklin, PA |
| Headline | Severe Thunderstorm Warning issued May 20 at 2:23PM EDT until May 20 at 2:30PM EDT by NWS State College PA |
| Expires | 2026-05-20T14:32:00-04:00 |
| SenderName | NWS State College PA |
| HasExactCoords | true |
| Iem TypeSummary | D |
| Iem City | 4 WNW Greencastle |
| Iem County | Franklin |
| Iem State | PA |
| Iem Wfo | CTP |
| Iem Remark | Wires down reported in Upton along Lemar Road and Buchanan Trail West. |
| MergedSources | [{"id":"iem_D_39.760_-77.860_1779298500000","source":"iem","severity":"low","severityValue":25,"timestamp":1779298500000,"latitude":39.76,"longitude":-77.86},{"id":"iem_D_39.810_-77.810_1779298980000","source":"iem","severity":"low","severityValue":25,"timestamp":1779298980000,"latitude":39.81,"longitude":-77.81}] |
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 43/100, near Chambersburg (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.