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

Nashville, Tennessee Revisions MILEPOST 1201

Nashville's forecast for Tuesday has moved 9°F colder

89°F in the 20260922T18:00Z run, 81°F in the 20260924T12:00Z — 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 8°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Tuesday, September 29 at 18Z in Nashville, that trail runs from 89.3°F in the 20260922T18:00Z cycle to 80.6°F in the 20260924T12:00Z — a move of -8.7°F across 8 runs.

The change is larger than the run's own 10th-to-90th percentile spread — the guidance did not merely narrow, it moved off its previous position.

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 Tuesday at 18Z
api.weather.city /v1/history (nbm-qmd)
-8.7 °F normal 0.0 °F · 3 of 6
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
8 °F normal 8.7 °F
current run
Milepost
1201 · 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
b7b15f603550e8caabe0274b9fd77673246b3bab27f564c4bee366ef0db40a77
Machine
JSON