Phoenix's forecast for Tuesday has moved 10°F colder
86°F in the 20260926T00:00Z run, 76°F in the 20260927T18:00Z — the 2nd-largest revision of the 7 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 11°F.
RevisionsMonday, September 28, 2026Phoenix, Arizona
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Milepost 1231
Successive cycles do not merely refresh a forecast; they leave a trail. For Tuesday, September 29 at 00Z in Phoenix, that trail runs from 85.8°F in the 20260926T00:00Z cycle to 75.6°F in the 20260927T18:00Z — a move of -10.1°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 Tuesday at 00Z api.weather.city /v1/history (nbm-qmd) |
-10.1 °F | normal 0.0 °F · 2 of 7 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
11.5 °F | normal 10.1 °F current run |
- Milepost
- 1231 · laid 2026-09-28T04:25:13Z
- Model
- nbm-qmd · cycle 20260927T18:00Z
- Desk
- revision v1
- Method
- the same valid time read from successive synoptic cycles; the move is last run minus first run
- Stores
- https://api.weather.city/v1/history
- Tagged
- I-500 Daily Weather · Phoenix, Arizona (33.448, -112.074) · by rule, at build
- Digest
- baaa7b3171ea52615c69e9761e6419da657192380d98948a124be21aed817f54