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Milepost
1444

TheForecast Post

A chronicle of American weather and climate  ·  Tuesday, 20 October 2026

Phoenix, Arizona Revisions MILEPOST 1444

Phoenix's forecast for Wednesday has moved 7°F warmer

73°F in the 20261018T06:00Z run, 80°F in the 20261020T00:00Z — the 3rd-largest revision of the 4 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 13°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Wednesday, October 28 at 00Z in Phoenix, that trail runs from 73.2°F in the 20261018T06:00Z cycle to 80.3°F in the 20261020T00:00Z — a move of +7.1°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 Wednesday at 00Z
api.weather.city /v1/history (nbm-qmd)
7.1 °F normal 0.0 °F · 3 of 4
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
12.5 °F normal 7.1 °F
current run
Milepost
1444 · laid 2026-10-20T10:25:18Z
Model
nbm-qmd · cycle 20261020T00:00Z
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
7eea697e9bd57df7fddbe35030c8bc724582c5237bc6762e2cd5bba84d475a8c
Machine
JSON