Chicago's forecast for Wednesday has moved 13°F colder
53°F in the 20261108T00:00Z run, 40°F in the 20261109T18:00Z — the 3rd-largest revision of the 8 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 14°F.
RevisionsTuesday, November 10, 2026Chicago, Illinois
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Milepost 1645
Successive cycles do not merely refresh a forecast; they leave a trail. For Wednesday, November 18 at 12Z in Chicago, that trail runs from 52.7°F in the 20261108T00:00Z cycle to 39.7°F in the 20261109T18:00Z — a move of -13.0°F across 8 runs.
The change is about half the run's 10th-to-90th percentile spread, so the earlier forecast is still inside the current range of outcomes.
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 Wednesday at 12Z api.weather.city /v1/history (nbm-qmd) |
-13 °F | normal 0.0 °F · 3 of 8 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
14.3 °F | normal 13.0 °F current run |
- Milepost
- 1645 · laid 2026-11-10T04:25:29Z
- Model
- nbm-qmd · cycle 20261109T18:00Z
- 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
- 0471e58aaa32fb7ac4bc46b4be103a03fe344660ce0b96c1ac70abe9def01f16