Chicago, Illinois Revisions
MILEPOST 1465
Chicago's forecast for Wednesday has moved 7°F warmer
49°F in the 20261020T06:00Z run, 57°F in the 20261022T00:00Z — the 3rd-largest revision of the 4 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 14°F.
Successive cycles do not merely refresh a forecast; they leave a trail. For Wednesday, October 28 at 00Z in Chicago, that trail runs from 49.4°F in the 20261020T06:00Z cycle to 56.7°F in the 20261022T00:00Z — a move of +7.3°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 00Z api.weather.city /v1/history (nbm-qmd) |
7.3 °F | normal 0.0 °F · 3 of 4 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
14.3 °F | normal 7.3 °F current run |
- Milepost
- 1465 · laid 2026-10-22T10:25:19Z
- Model
- nbm-qmd · cycle 20261022T00:00Z
- 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
- 0a9cf18194b6d65ee59c6facea46f17cae6956e17af7b71c148411f3e0a6e664
- Machine
- JSON