Phoenix, Arizona Revisions
MILEPOST 1155
Phoenix's forecast for Tuesday has moved 8°F colder
102°F in the 20260918T12:00Z run, 93°F in the 20260920T06:00Z — the 2nd-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 23°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 101.5°F in the 20260918T12:00Z cycle to 93.3°F in the 20260920T06:00Z — a move of -8.2°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) |
-8.2 °F | normal 0.0 °F · 2 of 3 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
22.7 °F | normal 8.2 °F current run |
- Milepost
- 1155 · laid 2026-09-20T17:25:19Z
- Model
- nbm-qmd · cycle 20260920T06:00Z
- 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
- db253e7e816629c1a9c763e4916c51b9aa16b8ca1f038a07e741910803ff75a4
- Machine
- JSON