Boston, Massachusetts Revisions
MILEPOST 1259
Boston's forecast for Sunday has moved 10°F warmer
54°F in the 20260930T06:00Z run, 64°F in the 20261001T00:00Z — the largest revision of any city on the roster. The current run's 10th-to-90th percentile spread at that hour is 21°F.
Successive cycles do not merely refresh a forecast; they leave a trail. For Sunday, October 11 at 18Z in Boston, that trail runs from 54.0°F in the 20260930T06:00Z cycle to 64.5°F in the 20261001T00:00Z — a move of +10.4°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 Sunday at 18Z api.weather.city /v1/history (nbm-qmd) |
10.4 °F | normal 0.0 °F · 1 of 9 8 synoptic cycles |
| 10th-to-90th percentile spread at that hour api.weather.city (nbm-qmd) |
21.1 °F | normal 10.4 °F current run |
- Milepost
- 1259 · laid 2026-10-01T10:25:12Z
- Model
- nbm-qmd · cycle 20261001T00:00Z
- 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
- 7934354897b364a068dc116ae656766e3fbaa7cf0befe1f0cecf4b813d9e56d9
- Machine
- JSON