Right now
The most recent data we hold from NOAA arrived 11 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 4 September 2026 at 03:30 UTC. It is kept here as a record.
No stronger detection stands among the 21 recorded within 20 km of this point since 18 May 2026 — 2 others scored the same. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 3 at 11:08PM EDT until September 3 at 11:30PM EDT by NWS Baltimore MD/Washington DC
Urban PEI: 42,354 within a heuristic 50 km radius; not unique people.
Nearby, since 18 May 2026
- July 4, 2026 · 6.8 km
- June 18, 2026 · 7.6 km
- September 5, 2026 · score 28 · 12.1 km
How we know
2 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 40 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 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) | 40 / 100 |
| Legacy data-support index | 0.87/1 |
| Coordinates | 39.1419, -78.5600 |
| Nearest City | Winchester (35 km) |
| Urban exposure index (PEI) | 42.4K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-04T03:08:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.c1758b8ff884ac5d66f58bd1cd360edb2e0f8fcd.002.1 |
Physical priority index · v4 (historical). 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: 2026-09-04T03:08:00.000Z.
First archived: 2026-09-04T03:11:20.021Z. 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 | Loudoun, VA; Tucker, WV; Baltimore, MD; Carroll, MD; Howard, MD and 2 more areas |
| Headline | Severe Thunderstorm Warning issued September 3 at 11:08PM EDT until September 3 at 11:30PM EDT by NWS Baltimore MD/Washington DC |
| Expires | 2026-09-03T23:30:00-04:00 |
| SenderName | NWS Baltimore MD/Washington DC |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.c1758b8ff884ac5d66f58bd1cd360edb2e0f8fcd.002.1","noaa_urn:oid:2.49.0.1.840.0.f0051a457ef2cdf010a8d59958a2e4962895d45f.001.1","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":1788491177954,"latitude":38.57,"longitude":-78.78},{"id":"spc_wind_39.72_-78.58_205","source":"spc","severity":"medium","severityValue":45,"timestamp":1788481680000,"latitude":39.72,"longitude":-78.58},{"id":"spc_wind_39.48_-79.24_210","source":"spc","severity":"medium","severityValue":45,"timestamp":1788484380000,"latitude":39.48,"longitude":-79.24},{"id":"spc_hail_38.59_-78.79_221","source":"spc","severity":"high","severityValue":65,"timestamp":1788491177955,"latitude":38.59,"longitude":-78.79},{"id":"spc_hail_38.58_-78.79_222","source":"spc","severity":"high","severityValue":65,"timestamp":1788491177955,"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.
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