Edition 2026-09-22 The Ledger Archive API RSS Weather Trader
Milepost
1177

TheForecast Post

A chronicle of American weather and climate  ·  Tuesday, 22 September 2026

Denver, Colorado Revisions MILEPOST 1176

Denver's forecast for Thursday has moved 9°F colder

80°F in the 20260920T06:00Z run, 71°F in the 20260922T00:00Z — the 2nd-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, September 24 at 21Z in Denver, that trail runs from 79.6°F in the 20260920T06:00Z cycle to 70.7°F in the 20260922T00:00Z — a move of -8.9°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 21Z
api.weather.city /v1/history (nbm-qmd)
-8.9 °F normal 0.0 °F · 2 of 4
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
16.5 °F normal 8.9 °F
current run
Milepost
1176 · laid 2026-09-22T10:25:12Z
Model
nbm-qmd · cycle 20260922T00:00Z
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
a09e354d4c287ba6e56fd4ffab5d6e5d83b147a6c2da95d01d15582257e3322a
Machine
JSON