This alert expired on 20 May 2026 at 20:00 UTC. It is kept here as a record.
It is the 6th strongest of the 71 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day. 10 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 20 at 3:24PM EDT until May 20 at 4:00PM EDT by NWS Baltimore MD/Washington DC
An estimated 154,774 people live within 50 km of this point.
Nearby, since 12 March 2026
- March 17, 2026 · score 43 · 3.4 km
- March 16, 2026 · score 43 · 3.4 km
- May 20, 2026 · score 43 · 7.0 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 43 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) | 43 / 100 |
| Our confidence | 80% |
| Coordinates | 39.0550, -78.0617 |
| Nearest City | Winchester (17 km) |
| Population Exposed | 154.8K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T19:24:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.bd26181b2c0736ba4cbc43272ec8d47ccce4bbca.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Clarke, VA; Frederick, VA; Warren, VA |
| Headline | Severe Thunderstorm Warning issued May 20 at 3:24PM EDT until May 20 at 4:00PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-05-20T16:00:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
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 Winchester?
Calamity.live data shows a weather event with CalamityScore 43/100, near Winchester (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 187 scientific monitoring sources.