Right now
The most recent data we hold from NOAA arrived 13 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 20 May 2026 at 19:04 UTC. It is kept here as a record.
It is the 19th strongest of the 129 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 2:55PM EDT until May 20 at 3:00PM EDT by NWS Baltimore MD/Washington DC
An estimated 60,054 people live within 50 km of this point.
Nearby, since 12 March 2026
- September 4, 2026 · score 45 · 3.0 km
- August 10, 2026 · score 39 · 9.8 km
- August 28, 2026 · score 34 · 13.6 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 39 out of 100, at 80 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 39 / 100 |
| Our confidence | 80% |
| Coordinates | 39.0913, -78.2720 |
| Nearest City | Winchester (15 km) |
| Population Exposed | 60.1K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T18:55:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.8573cb905f8769cc0069f8e995b03bba |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Frederick, VA; Hampshire, WV; Frederick, MD; Washington, MD; Loudoun, VA; Jefferson, WV; Page, VA; Shenandoah, VA |
| Headline | Severe Thunderstorm Warning issued May 20 at 2:55PM EDT until May 20 at 3:00PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-05-20T15:04:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.8573cb905f8769cc0069f8e995b03bba83c399c4.001.1","noaa_urn:oid:2.49.0.1.840.0.e51387fc3ef1d89d83eb58d8f114e09998b03ce7.001.1","noaa_urn:oid:2.49.0.1.840.0.07a69e0c1e04f067a6ab96e20f0fdea9c52bc3b6.001.1"] |
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 8 March 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.
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