Right now
The most recent data we hold from NOAA arrived 6 hours 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 July 2026 at 21:15 UTC. It is kept here as a record.
It is the 16th strongest of the 50 detections recorded within 20 km of this point since 10 March 2026. The last comparable one was on 3 July 2026. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 4 at 3:36PM CDT until July 4 at 4:15PM CDT by NWS Chicago IL
Urban PEI: 609,880 within a heuristic 50 km radius; not unique people.
Nearby, since 10 March 2026
- June 12, 2026 · score 41 · 10.9 km
- June 25, 2026 · score 39 · 15.7 km
- August 11, 2026 · score 52 · 17.7 km
How we know
2 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 48 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) | 48 / 100 |
| Legacy data-support index | 0.83/1 |
| Coordinates | 41.3595, -88.4731 |
| Nearest City | Shorewood (29 km) |
| Urban exposure index (PEI) | 609.9K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-04T20:36:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.7d583eb98f4ae526c87bac31a8ade1ee |
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: 2026-07-04T20:36:00.000Z.
First archived: 2026-07-04T20:41:01.120Z. 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 | DuPage, IL; Grundy, IL; Kendall, IL; Will, IL; Kane, IL; Kendall, IL; McLean, IL; Woodford, IL |
| Headline | Severe Thunderstorm Warning issued July 4 at 3:36PM CDT until July 4 at 4:15PM CDT by NWS Chicago IL |
| Expires | 2026-07-04T16:15:00-05:00 |
| SenderName | NWS Chicago IL |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.7d583eb98f4ae526c87bac31a8ade1eea14c4aba.001.1","noaa_urn:oid:2.49.0.1.840.0.f3dd7d5b42b876a847fad1673489f04482e6ee7a.001.1","noaa_urn:oid:2.49.0.1.840.0.d10e8fd2906c137bb6ddc00c0e7c78938c8b3af2.001.1"] |
| Iem TypeSummary | F |
| Iem City | Spring Valley |
| Iem County | Bureau |
| Iem State | IL |
| Iem Wfo | DVN |
| Iem Remark | Multiple roads in Spring Valley closed due to water. |
| MergedSources | [{"id":"iem_F_41.330_-89.200_1783195080000","source":"iem","severity":"low","severityValue":25,"timestamp":1783195080000,"latitude":41.33,"longitude":-89.2}] |
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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