This alert expired on 4 September 2026 at 04:00 UTC. It is kept here as a record.
It is the 5th strongest of the 67 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 3 at 11:13PM EDT until September 4 at 12:00AM EDT by NWS Baltimore MD/Washington DC
An estimated 60,054 people live within 50 km of this point.
Nearby, since 12 March 2026
- August 10, 2026 · score 39 · 9.0 km
- March 17, 2026 · score 43 · 12.3 km
- March 16, 2026 · score 43 · 12.3 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 45 out of 100, at 87 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | High |
| Calamity Score (ours) | 45 / 100 |
| Our confidence | 87% |
| Coordinates | 39.0908, -78.2368 |
| Nearest City | Winchester (13 km) |
| Population Exposed | 60.1K within 50 km |
| Impact Tier | severe |
| Timestamp | 2026-09-04T03:13:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.6bcee8226bb8c6c0303f7658c0921df12f512b40.001.1 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Montgomery, MD; Fairfax, VA; Loudoun, VA; Tucker, WV; Fairfax, VA; Loudoun, VA; Prince William, VA; City of Manassas, VA; City of Manassas Park, VA and 4 more areas |
| Headline | Severe Thunderstorm Warning issued September 3 at 11:13PM EDT until September 4 at 12:00AM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-09-04T00:00:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 7 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.6bcee8226bb8c6c0303f7658c0921df12f512b40.001.1","noaa_urn:oid:2.49.0.1.840.0.cacdb2c265c5ce5594fc4bc984466585bbbe0f5b.001.1","noaa_urn:oid:2.49.0.1.840.0.55997e2a6bed21980192a991e0762e8ad469d921.001.1","noaa_urn:oid:2.49.0.1.840.0.c1758b8ff884ac5d66f58bd1cd360edb2e0f8fcd.002.1","noaa_urn:oid:2.49.0.1.840.0.17d1907f38659f9d9b7fd342c66fb8c5d788d109.001.1","noaa_urn:oid:2.49.0.1.840.0.af660663dfb06f1df2f834b2e7fbad729dbb0b47.002.1","noaa_urn:oid:2.49.0.1.840.0.8d145367160b2a48360ffb6b830beede9ec9a80f.002.1"] |
| Spc ReportType | hail |
| Spc Speed | 175 |
| Spc Location | 2 S Broadway |
| Spc County | Rockingham |
| Spc State | VA |
| Spc Comments | Video footage showing golf ball size hail reported near Broadway. (LWX) |
| MergedSources | [{"id":"spc_wind_38.57_-78.78_28","source":"spc","severity":"medium","severityValue":45,"timestamp":1788491540524,"latitude":38.57,"longitude":-78.78},{"id":"spc_hail_38.59_-78.79_231","source":"spc","severity":"high","severityValue":65,"timestamp":1788491540524,"latitude":38.59,"longitude":-78.79},{"id":"spc_hail_38.58_-78.79_232","source":"spc","severity":"high","severityValue":65,"timestamp":1788491540524,"latitude":38.58,"longitude":-78.79}] |
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 Winchester?
Calamity.live data shows a weather event with CalamityScore 45/100, near Winchester (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.