Chicago, Illinois Revisions
MILEPOST 1472
Chicago's forecast for Wednesday has moved 6°F warmer
57°F in the 20261020T18:00Z run, 63°F in the 20261022T12:00Z — the 3rd-largest revision of the 3 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 17°F.
Successive cycles do not merely refresh a forecast; they leave a trail. For Wednesday, October 28 at 18Z in Chicago, that trail runs from 56.9°F in the 20261020T18:00Z cycle to 63.4°F in the 20261022T12:00Z — a move of +6.4°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 Wednesday at 18Z api.weather.city /v1/history (nbm-qmd) |
6.4 °F | normal 0.0 °F · 3 of 3 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
16.6 °F | normal 6.4 °F current run |
- Milepost
- 1472 · laid 2026-10-22T21:25:24Z
- Model
- nbm-qmd · cycle 20261022T12:00Z
- Desk
- revision v1
- Method
- the same valid time read from successive synoptic cycles; the move is last run minus first run
- Source
- https://api.weather.city/v1/history
- Digest
- 2681c12e86e3586830d8804464f46c650ef46d727b6163de5eb67d0194a5e0cc
- Machine
- JSON