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Milepost
1188

TheForecast Post

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

New York, New York Revisions MILEPOST 1187

New York's forecast for Friday has moved 7°F warmer

63°F in the 20260921T06:00Z run, 71°F in the 20260923T00:00Z — the 2nd-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 17°F.

Successive cycles do not merely refresh a forecast; they leave a trail. For Friday, September 25 at 18Z in New York, that trail runs from 63.1°F in the 20260921T06:00Z cycle to 70.5°F in the 20260923T00:00Z — a move of +7.4°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 18Z
api.weather.city /v1/history (nbm-qmd)
7.4 °F normal 0.0 °F · 2 of 5
8 synoptic cycles
10th-to-90th percentile spread at that hour
api.weather.city (nbm-qmd)
16.8 °F normal 7.4 °F
current run
Milepost
1187 · laid 2026-09-23T10:25:25Z
Model
nbm-qmd · cycle 20260923T00:00Z
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
2c236786515a1c40b3a1e91f9675e95e1d653e9024bbe25ce431e389bd9f809f
Machine
JSON