Edition 2026-09-19 The Ledger Archive API RSS Weather Trader
Milepost
1141

TheForecast Post

A chronicle of American weather and climate  ·  Saturday, 19 September 2026

Nashville, Tennessee Revisions MILEPOST 1141

Nashville's forecast for Wednesday has moved 7°F colder

86°F in the 20260917T06:00Z run, 79°F in the 20260919T00:00Z — the 3rd-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 12°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Wednesday, September 23 at 18Z in Nashville, that trail runs from 86.1°F in the 20260917T06:00Z cycle to 79.4°F in the 20260919T00:00Z — a move of -6.7°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 Wednesday at 18Z
api.weather.city /v1/history (nbm-qmd)
-6.7 °F normal 0.0 °F · 3 of 5
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
12.4 °F normal 6.7 °F
current run
Milepost
1141 · laid 2026-09-19T11:25:16Z
Model
nbm-qmd · cycle 20260919T00:00Z
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
747c50b3ae2e9b3cab4d927be5d493d4b72fb313e51748bc8cf5e252f0d2278e
Machine
JSON