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Milepost
1119

TheForecast Post

A chronicle of American weather and climate  ·  Thursday, 17 September 2026

Minneapolis, Minnesota Revisions MILEPOST 1114

Minneapolis's forecast for Tuesday has moved 10°F colder

72°F in the 20260915T06:00Z run, 62°F in the 20260916T18:00Z — the largest revision of any city on the roster. The current run's 10th-to-90th percentile spread at that hour is 10°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Tuesday, September 22 at 21Z in Minneapolis, that trail runs from 72.2°F in the 20260915T06:00Z cycle to 61.8°F in the 20260916T18:00Z — a move of -10.4°F across 8 runs.

The change is larger than the run's own 10th-to-90th percentile spread — the guidance did not merely narrow, it moved off its previous position.

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 Tuesday at 21Z
api.weather.city /v1/history (nbm-qmd)
-10.4 °F normal 0.0 °F · 1 of 4
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
10.1 °F normal 10.4 °F
current run
Milepost
1114 · laid 2026-09-17T10:25:25Z
Model
nbm-qmd · cycle 20260916T18:00Z
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
76eab89e6200cdee562723d0fac6b30049ef3dbbb32749b62b458c9e0069c77f
Machine
JSON