Chicago's forecast for Monday has moved 8°F colder
50°F in the 20261113T00:00Z run, 42°F in the 20261114T18:00Z — the 3rd-largest revision of the 6 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 18°F.
RevisionsSunday, November 15, 2026Chicago, Illinois
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Milepost 1694
Successive cycles do not merely refresh a forecast; they leave a trail. For Monday, November 23 at 18Z in Chicago, that trail runs from 49.7°F in the 20261113T00:00Z cycle to 42.0°F in the 20261114T18:00Z — a move of -7.7°F across 8 runs.
The change sits well inside the run's own spread, which is the guidance converging rather than reversing.
Model NBM-QMD, via api.weather.city /v1/history. Percentiles are the same run's own.
The numbers in this piece, with what they are measured against
| forecast revision for Monday at 18Z api.weather.city /v1/history (nbm-qmd) |
-7.7 °F | normal 0.0 °F · 3 of 6 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
18 °F | normal 7.7 °F current run |
- Milepost
- 1694 · laid 2026-11-15T04:25:35Z
- Model
- nbm-qmd · cycle 20261114T18:00Z
- Desk
- revision v1
- Method
- the same valid time read from successive synoptic cycles; the move is last run minus first run
- Stores
- https://api.weather.city/v1/history
- Tagged
- I-500 Daily Weather · Chicago, Illinois (41.878, -87.63) · by rule, at build
- Digest
- 0eef320b48ce0bcb14641a8bcc3bc5989da60d90415b4211246fe7ccd0dca8e4