Chicago, Illinois Revisions
MILEPOST 1036
Chicago's forecast for Monday has moved 10°F warmer
73°F in the 20260908T06:00Z run, 83°F in the 20260910T00:00Z — 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 21°F.
Successive cycles do not merely refresh a forecast; they leave a trail. For Monday, September 14 at 21Z in Chicago, that trail runs from 73.4°F in the 20260908T06:00Z cycle to 83.2°F in the 20260910T00:00Z — a move of +9.9°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 21Z api.weather.city /v1/history (nbm-qmd) |
9.9 °F | normal 0.0 °F · 3 of 6 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
20.9 °F | normal 9.9 °F current run |
- Milepost
- 1036 · laid 2026-09-10T12:29:55Z
- Model
- nbm-qmd · cycle 20260910T00:00Z
- 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
- 4ce56d6b76df9178d0421208724ff9538119587f32ca628fa12d049bf404ef2c
- Machine
- JSON