Edition 2026-09-30 The Ledger Archive API RSS Weather Trader
Milepost
1250

TheForecast Post

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

Nashville, Tennessee Revisions MILEPOST 1250

Nashville's forecast for Friday has moved 8°F colder

90°F in the 20260928T06:00Z run, 82°F in the 20260930T00:00Z — 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 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 89.8°F in the 20260928T06:00Z cycle to 81.8°F in the 20260930T00:00Z — a move of -8.0°F across 8 runs.

The change sits well inside the run's own spread, which is the guidance converging rather than reversing.

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)
-8 °F normal 0.0 °F · 3 of 6
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
16.9 °F normal 8.0 °F
current run
Milepost
1250 · laid 2026-09-30T10:25:14Z
Model
nbm-qmd · cycle 20260930T00:00Z
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
411bf2a2abd71083accbe90b083ae7522ae2eb1e83b8f5e2b2d9bfc3ff1e9f0a
Machine
JSON