Edition 2026-09-30 The Ledger Archive API RSS Weather Trader
Milepost
1253

TheForecast Post

A chronicle of American weather and climate  ·  Wednesday, 30 September 2026

Nashville, Tennessee Revisions MILEPOST 1252

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

89°F in the 20260928T12:00Z run, 80°F in the 20260930T06:00Z — the 2nd-largest revision of the 5 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 17°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Friday, October 2 at 21Z in Nashville, that trail runs from 89.2°F in the 20260928T12:00Z cycle to 80.2°F in the 20260930T06:00Z — a move of -9.0°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 Friday at 21Z
api.weather.city /v1/history (nbm-qmd)
-9 °F normal 0.0 °F · 2 of 5
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
17.3 °F normal 9.0 °F
current run
Milepost
1252 · laid 2026-09-30T16:25:15Z
Model
nbm-qmd · cycle 20260930T06:00Z
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
4d3ae74e059e278742a6e5cc93557e38732d874ed278a97f01dc135bcce83ee6
Machine
JSON