Phoenix, Arizona Revisions
MILEPOST 1144
Phoenix's forecast for Tuesday has moved 7°F colder
103°F in the 20260917T18:00Z run, 96°F in the 20260919T12:00Z — the largest revision of any city on the roster. The current run's 10th-to-90th percentile spread at that hour is 19°F.
Successive cycles do not merely refresh a forecast; they leave a trail. For Tuesday, September 29 at 00Z in Phoenix, that trail runs from 102.6°F in the 20260917T18:00Z cycle to 95.6°F in the 20260919T12:00Z — a move of -6.9°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 Tuesday at 00Z api.weather.city /v1/history (nbm-qmd) |
-6.9 °F | normal 0.0 °F · 1 of 3 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
18.9 °F | normal 6.9 °F current run |
- Milepost
- 1144 · laid 2026-09-19T22:25:21Z
- Model
- nbm-qmd · cycle 20260919T12:00Z
- 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
- 8b84c5c906692d67493aa19d2ec6b6dbd4eca4fefdb73cf14a6b85e28cd0f452
- Machine
- JSON