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 19:30 UTC. It is kept here as a record.
It is the 36th strongest of the 161 detections recorded within 20 km of this point since 12 March 2026. 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 3:14PM EDT until May 20 at 3:30PM EDT by NWS Baltimore MD/Washington DC
An estimated 917,219 people live within 50 km of this point.
Nearby, since 12 March 2026
- September 3, 2026 · score 41 · 1.5 km
- September 2, 2026 · score 41 · 1.5 km
- August 28, 2026 · score 48 · 5.2 km
How we know
Confirmed by 4 independent sources, including NOAA.
Our own score for this event is 48 out of 100, at 91 % 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) | 48 / 100 |
| Our confidence | 91% |
| Coordinates | 39.2430, -77.6686 |
| Nearest City | Leesburg (17 km) |
| Population Exposed | 917.2K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T19:14:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.d8b5a2aaf5c67c4bac7271b6a01cd6c5 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Loudoun, VA; Frederick, MD; Washington, MD; Loudoun, VA; Jefferson, WV |
| Headline | Severe Thunderstorm Warning issued May 20 at 3:14PM EDT until May 20 at 3:30PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-05-20T15:30:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.d8b5a2aaf5c67c4bac7271b6a01cd6c55b6ea231.001.1","noaa_urn:oid:2.49.0.1.840.0.c83f1acf2d76de3614bce406b95f08d274f4e530.001.1"] |
| 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. |
| Google News RssFeed | weather |
| Google News SourceName | The Washington Post |
| 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},{"id":"gnews_weather_494250_192","source":"google_news","severity":"medium","severityValue":40,"timestamp":1779302743000,"latitude":38.9,"longitude":-77.04}] |
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.
Want to know when something happens near Leesburg?
Calamity.live data shows a weather event with CalamityScore 48/100, near Leesburg (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.