Edition 2026-09-28 The Ledger Archive API RSS Weather Trader
Milepost
1232

TheForecast Post

A chronicle of American weather and climate  ·  Monday, 28 September 2026

Atlanta, Georgia Revisions MILEPOST 1230

Atlanta's forecast for Monday has moved 11°F colder

81°F in the 20260925T18:00Z run, 71°F in the 20260927T18:00Z — the largest revision of any city on the roster. 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 Monday, October 5 at 18Z in Atlanta, that trail runs from 81.2°F in the 20260925T18:00Z cycle to 70.6°F in the 20260927T18:00Z — a move of -10.6°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 Monday at 18Z
api.weather.city /v1/history (nbm-qmd)
-10.6 °F normal 0.0 °F · 1 of 7
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
16.4 °F normal 10.6 °F
current run
Milepost
1230 · laid 2026-09-28T04:25:13Z
Model
nbm-qmd · cycle 20260927T18:00Z
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
47762b5218537c6fe17b7f13583d3f9d85ee9e849bf8e10bd0e7efc6a1aa0553
Machine
JSON