Edition 2026-09-25 The Ledger Archive API RSS Weather Trader
Milepost
1202

TheForecast Post

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

Denver, Colorado Revisions MILEPOST 1200

Denver's forecast for Wednesday has moved 10°F colder

71°F in the 20260922T18:00Z run, 61°F in the 20260924T12:00Z — the 2nd-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 18°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Wednesday, September 30 at 00Z in Denver, that trail runs from 70.8°F in the 20260922T18:00Z cycle to 60.7°F in the 20260924T12:00Z — 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 Wednesday at 00Z
api.weather.city /v1/history (nbm-qmd)
-10.1 °F normal 0.0 °F · 2 of 6
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
17.6 °F normal 10.1 °F
current run
Milepost
1200 · laid 2026-09-24T22:25:15Z
Model
nbm-qmd · cycle 20260924T12:00Z
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
337d321631f628551fcbd1fe24b011cb6726921f4aed8facd0ccda3e6a6d50a0
Machine
JSON