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Milepost
1157

TheForecast Post

A chronicle of American weather and climate  ·  Sunday, 20 September 2026

Minneapolis, Minnesota Revisions MILEPOST 1156

Minneapolis's forecast for Thursday has moved 7°F colder

71°F in the 20260918T12:00Z run, 64°F in the 20260920T06:00Z — the 3rd-largest revision of the 3 cities on the roster that moved at all. The current run's 10th-to-90th percentile spread at that hour is 8°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Thursday, September 24 at 21Z in Minneapolis, that trail runs from 70.6°F in the 20260918T12:00Z cycle to 64.0°F in the 20260920T06:00Z — a move of -6.6°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 21Z
api.weather.city /v1/history (nbm-qmd)
-6.6 °F normal 0.0 °F · 3 of 3
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
8.1 °F normal 6.6 °F
current run
Milepost
1156 · laid 2026-09-20T17:25:20Z
Model
nbm-qmd · cycle 20260920T06:00Z
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
f99504db71db9b440a8b3faa3a1b0bb0027217a792698c27a99122a6904852dc
Machine
JSON