Right now
The most recent data we hold from NOAA arrived 21 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 11 June 2026 at 23:35 UTC. It is kept here as a record.
It is the 19th strongest of the 35 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued June 11 at 7:25PM EDT until June 11 at 7:30PM EDT by NWS Baltimore MD/Washington DC
Urban PEI: 114,432 within a heuristic 50 km radius; not unique people.
Nearby, since 16 March 2026
- July 28, 2026 · score 39 · 9.0 km
- June 15, 2026 · score 43 · 11.4 km
- July 4, 2026 · score 43 · 13.2 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 37 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
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) | 37 / 100 |
| Legacy data-support index | 0.80/1 |
| Coordinates | 39.8710, -77.4262 |
| Nearest City | Chambersburg (21 km) |
| Urban exposure index (PEI) | 114.4K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-11T23:25:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.d5424ca84cfa6b5d5a1d0c4c6409a946 |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-06-11T23:25:00.000Z.
First archived: 2026-06-11T23:27:32.113Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Frederick, MD; Washington, MD; Clarke, VA; Fauquier, VA; Frederick, VA; Loudoun, VA; Warren, VA; Berkeley, WV; Jefferson, WV; Clarke, VA; Culpeper, VA; Fauquier, VA; Frederick, VA; Greene, VA; Madison, VA; Page, VA; Rappahannock, VA; Warren, VA; Carroll, MD; Frederick, MD; Howard, MD; Montgomery, MD; Washington, MD; Clarke, VA; Culpeper, VA; Fairfax, VA; Fauquier, VA; Loudoun, VA; Madison, VA; Orange, VA; Prince William, VA; Rappahannock, VA; Stafford, VA; City of Fairfax, VA; City of Manassas, VA; City of Manassas Park, VA; Jefferson, WV and 7 more areas |
| Headline | Severe Thunderstorm Warning issued June 11 at 7:25PM EDT until June 11 at 7:30PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-06-11T19:35:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 10 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.d5424ca84cfa6b5d5a1d0c4c6409a946679e263f.001.1","noaa_urn:oid:2.49.0.1.840.0.82e0f60ebe2a47dbcc7095bfed6e18ef019cdbc4.001.1","noaa_urn:oid:2.49.0.1.840.0.5b7dd09fa4ad97260dc9ec8f5d19a749dcb49b7a.001.1","noaa_urn:oid:2.49.0.1.840.0.530af76c05ffcf72a17f538856e05f663d31f393.001.1","noaa_urn:oid:2.49.0.1.840.0.05e5667214661487462636505454e1b02c4310ef.001.1","noaa_urn:oid:2.49.0.1.840.0.d64fc5d7bd60f5452dc1d5a2054a60efe05094a2.001.1","noaa_urn:oid:2.49.0.1.840.0.4e09187da0cd2227be4e4a2c820252334ce5d3e7.001.1","noaa_urn:oid:2.49.0.1.840.0.c67226efbb9e0558e3f83222998ff8c97b177dd4.001.1","noaa_urn:oid:2.49.0.1.840.0.b9a7b8c8cb8b8ee65d1ec49598f7677d79ffef41.001.1","noaa_urn:oid:2.49.0.1.840.0.5837bdc04cddd177e0f2189dc324b528add4c3ed.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.
Review the area, threshold and delivery channel in your account.
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