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Milepost
1191

TheForecast Post

A chronicle of American weather and climate  ·  Wednesday, 23 September 2026

Dallas, Texas Revisions MILEPOST 1189

Dallas's forecast for Thursday has moved 12°F colder

91°F in the 20260921T12:00Z run, 79°F in the 20260923T06:00Z — the largest revision of any city on the roster. The current run's 10th-to-90th percentile spread at that hour is 22°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Thursday, October 1 at 18Z in Dallas, that trail runs from 91.2°F in the 20260921T12:00Z cycle to 78.9°F in the 20260923T06:00Z — a move of -12.3°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 Thursday at 18Z
api.weather.city /v1/history (nbm-qmd)
-12.3 °F normal 0.0 °F · 1 of 8
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
22.2 °F normal 12.3 °F
current run
Milepost
1189 · laid 2026-09-23T17:25:13Z
Model
nbm-qmd · cycle 20260923T06:00Z
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
e8c8474b1ea00de5d1bd10c1c90adb879a700b9a2c0eabba8b1e485a15cec89f
Machine
JSON