This alert expired on 27 August 2026 at 23:30 UTC. It is kept here as a record.
It is the 3rd strongest of the 192 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 August 27 at 6:50PM EDT until August 27 at 7:30PM EDT by NWS Baltimore MD/Washington DC
An estimated 151,695 people live within 50 km of this point.
Nearby, since 12 March 2026
- May 18, 2026 · score 43 · 5.7 km
- May 13, 2026 · score 43 · 10.5 km
- May 18, 2026 · score 43 · 14.1 km
How we know
Confirmed by 14 independent sources, including NOAA.
Our own score for this event is 49 out of 100, at 89 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | high |
| Calamity Score (ours) | 49 / 100 |
| Our confidence | 89% |
| Coordinates | 39.2960, -78.0249 |
| Nearest City | Winchester (17 km) |
| Population Exposed | 151.7K within 50 km |
| Impact Tier | severe |
| Timestamp | 2026-08-27T22:50:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.66a452d1c8f89249c49bdf6f23969e43 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Frederick, VA; Hampshire, WV; Frederick, MD; Montgomery, MD; Washington, MD; Loudoun, VA |
| Headline | Severe Thunderstorm Warning issued August 27 at 6:50PM EDT until August 27 at 7:30PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-08-27T19:30:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.66a452d1c8f89249c49bdf6f23969e435356f118.001.1","noaa_urn:oid:2.49.0.1.840.0.f632014beb2873e1654c0aaa85d9b8c9a83f7c14.002.1"] |
| Spc ReportType | hail |
| Spc Speed | 100 |
| Spc Location | Shepherdstown |
| Spc County | Jefferson |
| Spc State | WV |
| Spc Comments | Quarter size hail in Shepherdstown (LWX) |
| MergedSources | [{"id":"spc_wind_38.93_-78.48_22","source":"spc","severity":"medium","severityValue":45,"timestamp":1787859900000,"latitude":38.93,"longitude":-78.48},{"id":"spc_wind_38.92_-78.42_23","source":"spc","severity":"medium","severityValue":45,"timestamp":1787860200000,"latitude":38.92,"longitude":-78.42},{"id":"spc_wind_39.09_-78.43_49","source":"spc","severity":"medium","severityValue":45,"timestamp":1787864280000,"latitude":39.09,"longitude":-78.43},{"id":"spc_wind_39.44_-77.99_56","source":"spc","severity":"medium","severityValue":45,"timestamp":1787865600000,"latitude":39.44,"longitude":-77.99},{"id":"spc_wind_39.46_-77.98_57","source":"spc","severity":"medium","severityValue":45,"timestamp":1787865600000,"latitude":39.46,"longitude":-77.98},{"id":"spc_wind_39.44_-77.98_67","source":"spc","severity":"medium","severityValue":45,"timestamp":1787866440000,"latitude":39.44,"longitude":-77.98},{"id":"spc_wind_39.03_-78.47_70","source":"spc","severity":"medium","severityValue":45,"timestamp":1787866620000,"latitude":39.03,"longitude":-78.47},{"id":"spc_wind_39.44_-77.98_73","source":"spc","severity":"medium","severityValue":45,"timestamp":1787867040000,"latitude":39.44,"longitude":-77.98},{"id":"spc_wind_39.55_-77.80_78","source":"spc","severity":"medium","severityValue":45,"timestamp":1787867700000,"latitude":39.55,"longitude":-77.8},{"id":"spc_hail_39.44_-77.98_90","source":"spc","severity":"high","severityValue":65,"timestamp":1787865300000,"latitude":39.44,"longitude":-77.98},{"id":"spc_hail_39.46_-77.98_91","source":"spc","severity":"high","severityValue":65,"timestamp":1787865600000,"latitude":39.46,"longitude":-77.98},{"id":"spc_hail_39.45_-77.97_93","source":"spc","severity":"high","severityValue":65,"timestamp":1787866620000,"latitude":39.45,"longitude":-77.97},{"id":"spc_hail_39.43_-77.81_95","source":"spc","severity":"high","severityValue":65,"timestamp":1787868000000,"latitude":39.43,"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.
Want to know when something happens near Winchester?
Calamity.live data shows a weather event with CalamityScore 49/100, near Winchester (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 187 scientific monitoring sources.