Edition 2026-10-17 The Ledger Archive API RSS Weather Trader
Milepost
1411

TheForecast Post

A chronicle of American weather and climate  ·  Saturday, 17 October 2026

Phoenix, Arizona Revisions MILEPOST 1411

Phoenix's forecast for Thursday has moved 8°F warmer

73°F in the 20261015T06:00Z run, 81°F in the 20261017T00:00Z — 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 16°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Thursday, October 22 at 00Z in Phoenix, that trail runs from 73.4°F in the 20261015T06:00Z cycle to 81.5°F in the 20261017T00:00Z — a move of +8.0°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 Thursday at 00Z
api.weather.city /v1/history (nbm-qmd)
8 °F normal 0.0 °F · 3 of 4
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
15.8 °F normal 8.0 °F
current run
Milepost
1411 · laid 2026-10-17T10:25:18Z
Model
nbm-qmd · cycle 20261017T00:00Z
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
c13d95324d6a869ef8ac8764bf7a60151c074f09b0f1504a22dbbc9feed2c0ef
Machine
JSON