Edition 2026-09-25 The Ledger Archive API RSS Weather Trader
Milepost
1211

TheForecast Post

A chronicle of American weather and climate  ·  Friday, 25 September 2026

Denver, Colorado Revisions MILEPOST 1211

Denver's forecast for Sunday has moved 13°F colder

69°F in the 20260923T12:00Z run, 56°F in the 20260925T06:00Z — the 3rd-largest revision of the 6 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 28°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Sunday, October 4 at 18Z in Denver, that trail runs from 68.7°F in the 20260923T12:00Z cycle to 55.9°F in the 20260925T06:00Z — a move of -12.9°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 Sunday at 18Z
api.weather.city /v1/history (nbm-qmd)
-12.9 °F normal 0.0 °F · 3 of 6
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
27.6 °F normal 12.9 °F
current run
Milepost
1211 · laid 2026-09-25T16:25:16Z
Model
nbm-qmd · cycle 20260925T06:00Z
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
6d03ee3ca872cd34d85dc6a2950fcc482023210bded237f20e9e83a36b5a53fe
Machine
JSON