Edition 2026-09-17 The Ledger Archive API RSS Weather Trader
Milepost
1111

TheForecast Post

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

The Ledger The Ledger MILEPOST 1111

The ledger, through September 17

Mean absolute temperature error runs 2.23°F at day 1 and 3.66°F at day 7, over 441,494 settled forecast-observation pairs.

Every forecast this network publishes for a station with an ASOS report is compared against that report once the valid time has passed, and the residual is written down. This is the standing table for August 18–September 17, 2026.

LeadNDFDNBMpairs
Day 12.282.2367,341
Day 22.472.4265,834
Day 32.722.6363,334
Day 42.962.8560,980
Day 53.253.1258,585
Day 63.543.4256,174
Day 73.823.6643,716
Day 83.9625,530

Mean absolute error, °F, temperature. ASOS reports at :53 and the forecast is stamped on the hour, so a forecast is paired with the nearest observation within 30 minutes and otherwise left unscored.

The numbers in this piece, with what they are measured against
day-1 mean absolute temperature error, NBM
Forecast Network verification ledger
2.23 °F of 33,815
August 18–September 17, 2026
day-3 mean absolute temperature error, NBM
Forecast Network verification ledger
2.63 °F of 31,471
August 18–September 17, 2026
day-5 mean absolute temperature error, NBM
Forecast Network verification ledger
3.12 °F of 29,148
August 18–September 17, 2026
day-7 mean absolute temperature error, NBM
Forecast Network verification ledger
3.66 °F of 26,735
August 18–September 17, 2026
day-1 mean absolute temperature error, NDFD
Forecast Network verification ledger
2.28 °F of 33,526
August 18–September 17, 2026
day-3 mean absolute temperature error, NDFD
Forecast Network verification ledger
2.72 °F of 31,863
August 18–September 17, 2026
day-5 mean absolute temperature error, NDFD
Forecast Network verification ledger
3.25 °F of 29,437
August 18–September 17, 2026
day-7 mean absolute temperature error, NDFD
Forecast Network verification ledger
3.82 °F of 16,981
August 18–September 17, 2026
Milepost
1111 · laid 2026-09-17T00:25:14Z
Desk
ledger v1
Method
ASOS reports at :53 and the forecast is stamped on the hour, so a forecast is paired with the nearest observation within 30 minutes and otherwise left unscored.
Source
/home/maue/forecastpoints/data/verify/2026-08.ndjson
/home/maue/forecastpoints/data/verify/2026-09.ndjson
Digest
037a7c915551071d2773f064247f268f8ab4336055e4beaad615898db84aee90
Machine
JSON