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Milepost
1108

TheForecast Post

A chronicle of American weather and climate  ·  Wednesday, 16 September 2026

Minneapolis, Minnesota Revisions MILEPOST 1090

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

74°F in the 20260913T06:00Z run, 65°F in the 20260915T00:00Z — the largest revision of any city on the roster. The current run's 10th-to-90th percentile spread at that hour is 20°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Friday, September 18 at 21Z in Minneapolis, that trail runs from 74.5°F in the 20260913T06:00Z cycle to 65.3°F in the 20260915T00:00Z — a move of -9.2°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)
-9.2 °F normal 0.0 °F · 1 of 4
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
19.8 °F normal 9.2 °F
current run
Milepost
1090 · laid 2026-09-15T10:25:13Z
Model
nbm-qmd · cycle 20260915T00:00Z
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
10f0973bb6dfece9a0eaf96bdbbecf4833101183ae61958df34a7d01f653fcc9
Machine
JSON