Right now
The most recent data we hold from NOAA arrived 2 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 28 July 2026 at 22:15 UTC. It is kept here as a record.
It is the 4th strongest of the 133 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day. 5 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 28 at 5:22PM EDT until July 28 at 6:15PM EDT by NWS Mount Holly NJ
Urban PEI: 4,781,996 within a heuristic 50 km radius; not unique people.
Nearby, since 12 March 2026
- March 16, 2026 · score 52 · 6.1 km
- July 28, 2026 · score 52 · 7.7 km
- July 28, 2026 · score 52 · 9.7 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 52 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) | 52 / 100 |
| Legacy data-support index | 0.80/1 |
| Coordinates | 39.2411, -76.8469 |
| Nearest City | Columbia (1 km) |
| Urban exposure index (PEI) | 4.8M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-28T21:22:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.df5c3223901507e5fc67eb8535b70999 |
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: 2026-07-28T21:22:00.000Z.
First archived: 2026-07-28T21:25:35.784Z. 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 | Hunterdon, NJ; Bucks, PA; Baltimore, MD; Harford, MD; Culpeper, VA; Fauquier, VA and 6 more areas |
| Headline | Severe Thunderstorm Warning issued July 28 at 5:22PM EDT until July 28 at 6:15PM EDT by NWS Mount Holly NJ |
| Expires | 2026-07-28T18:15:00-04:00 |
| SenderName | NWS Mount Holly NJ |
| HasExactCoords | true |
| MergedCount | 11 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.df5c3223901507e5fc67eb8535b7099981061121.001.1","noaa_urn:oid:2.49.0.1.840.0.c29804521a06fd0a73bfbad4ed38cd43148b0518.002.1","noaa_urn:oid:2.49.0.1.840.0.5d3c948895732385ba23d9c244992f1af712b1e8.001.1","noaa_urn:oid:2.49.0.1.840.0.fefda9019124bc7ef62c4a759c4ee955400c57c5.001.1","noaa_urn:oid:2.49.0.1.840.0.1a0b4dfd1df90b57c71b2706af9a89ebfd155e80.001.1","noaa_urn:oid:2.49.0.1.840.0.54db5880ce3d315c7a30aa5a25cff64af347ff2d.002.1","noaa_urn:oid:2.49.0.1.840.0.7e97f0f092242e34ee65a08d4c260fd529db9ee0.001.1","noaa_urn:oid:2.49.0.1.840.0.75b9d0105fccc24de5deac32c4e23f34dc14f60e.001.1","noaa_urn:oid:2.49.0.1.840.0.65fd9f91ca824e1d59a03aeaa8c1cc1770b914a8.001.1","noaa_urn:oid:2.49.0.1.840.0.45b27fdf91fb1a7bb3285790b279d47aec982d16.001.1","noaa_urn:oid:2.49.0.1.840.0.40066cb669fe5f40ef3243de93f43246480f333a.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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