Right now
The most recent data we hold from NOAA arrived 4 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 21 July 2026 at 23:15 UTC. It is kept here as a record.
It is the 9th strongest of the 36 detections recorded within 20 km of this point since 12 June 2026. The last comparable one was on 5 July 2026.
What the source measured
NOAA reported: Flash Flood Warning issued July 21 at 3:13PM EDT until July 21 at 7:15PM EDT by NWS Mount Holly NJ
Urban PEI: 8,126,629 within a heuristic 50 km radius; not unique people.
Nearby, since 12 June 2026
- July 21, 2026 · score 46 · 4.6 km
- July 21, 2026 · score 46 · 5.8 km
- July 21, 2026 · score 46 · 8.9 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 46 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) | 46 / 100 |
| Legacy data-support index | 0.79/1 |
| Coordinates | 41.1756, -74.0827 |
| Nearest City | Monsey (7 km) |
| Urban exposure index (PEI) | 8.1M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-21T19:13:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.b0ef6fcf6aafa17ce5a0bb851b3f2f71 |
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: 2026-07-21T19:13:00.000Z.
First archived: 2026-07-21T19:39:25.686Z. 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 | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Morris, NJ; Somerset, NJ; Bergen, NJ; Essex, NJ; Hudson, NJ; Passaic, NJ; Morris, NJ and 2 more areas |
| Headline | Flash Flood Warning issued July 21 at 3:13PM EDT until July 21 at 7:15PM EDT by NWS Mount Holly NJ |
| Expires | 2026-07-21T19:15:00-04:00 |
| SenderName | NWS Mount Holly NJ |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.b0ef6fcf6aafa17ce5a0bb851b3f2f719f8b98c9.001.1","noaa_urn:oid:2.49.0.1.840.0.8f2a5d78aa0e63a8239c1a12541b92f3f9144c5d.001.1","noaa_urn:oid:2.49.0.1.840.0.2a0d52052d48ca435e1a3e6d885d1a1db52ff303.001.1","noaa_urn:oid:2.49.0.1.840.0.8b322d9b64c3bd27e94ae01b96c72e8b5c97166c.001.1","noaa_urn:oid:2.49.0.1.840.0.62e57cace57768369f29fe2a609372c4cbb37f03.001.1"] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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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