Chicago, Illinois Revisions
MILEPOST 1356
Chicago's forecast for Tuesday has moved 15°F warmer
63°F in the 20261009T06:00Z run, 79°F in the 20261011T00:00Z — the 3rd-largest revision of the 9 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 Tuesday, October 13 at 21Z in Chicago, that trail runs from 63.4°F in the 20261009T06:00Z cycle to 78.5°F in the 20261011T00:00Z — a move of +15.1°F across 8 runs.
The change is larger than the run's own 10th-to-90th percentile spread — the guidance did not merely narrow, it moved off its previous position.
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 Tuesday at 21Z api.weather.city /v1/history (nbm-qmd) |
15.1 °F | normal 0.0 °F · 3 of 9 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
13.9 °F | normal 15.1 °F current run |
- Milepost
- 1356 · laid 2026-10-11T10:25:15Z
- Model
- nbm-qmd · cycle 20261011T00:00Z
- 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
- 44cdf2370d84b3fda9a146e6909f038dde2a9065da98681cadcf5adf7689c53c
- Machine
- JSON