This alert expired on 18 July 2026 at 18:45 UTC. It is kept here as a record.
It is the 152nd strongest of the 240 detections recorded within 20 km of this point since 12 March 2026. The last comparable one was on 9 July 2026. 11 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 18 at 2:12PM EDT until July 18 at 2:45PM EDT by NWS Baltimore MD/Washington DC
An estimated 470,597 people live within 50 km of this point.
Nearby, since 12 March 2026
- July 21, 2026 · score 41 · 5.5 km
- August 10, 2026 · score 43 · 6.5 km
- June 11, 2026 · score 37 · 6.9 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 | 39.2766, -77.7725 |
| Nearest City | Leesburg (25 km) |
| Population Exposed | 470.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-18T18:12:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.342aadd53a58f384783bba223f55887a |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Frederick, MD; Washington, MD; Clarke, VA; Loudoun, VA; Jefferson, WV; Frederick, MD; Clarke, VA; Frederick, VA; Berkeley, WV; Jefferson, WV |
| Headline | Severe Thunderstorm Warning issued July 18 at 2:12PM EDT until July 18 at 2:45PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-07-18T14:45:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.342aadd53a58f384783bba223f55887a6b610efb.001.1","noaa_urn:oid:2.49.0.1.840.0.103ab6d3237638531ce5a8ae8a2f3851cd360fef.001.1","noaa_urn:oid:2.49.0.1.840.0.1796f09b4d847fe1555df348bdd508286897fb64.002.1"] |
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 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.
Calamity.live data shows a weather event with CalamityScore 43/100, near Leesburg (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.