Edition 2026-09-29 The Ledger Archive API RSS Weather Trader
Milepost
1240

TheForecast Post

A chronicle of American weather and climate  ·  Tuesday, 29 September 2026

Nashville, Tennessee Revisions MILEPOST 1240

Nashville's forecast for Tuesday has moved 10°F colder

64°F in the 20260927T00:00Z run, 54°F in the 20260928T18:00Z — the 2nd-largest revision of the 8 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 Tuesday, October 6 at 12Z in Nashville, that trail runs from 64.5°F in the 20260927T00:00Z cycle to 54.5°F in the 20260928T18:00Z — a move of -10.0°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 Tuesday at 12Z
api.weather.city /v1/history (nbm-qmd)
-10 °F normal 0.0 °F · 2 of 8
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
17.8 °F normal 10.0 °F
current run
Milepost
1240 · laid 2026-09-29T04:25:14Z
Model
nbm-qmd · cycle 20260928T18:00Z
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
157fd216518a9dab77d9196737daa646a466c374a1b383ce1f1cd01d44e1046f
Machine
JSON