Edition 2026-09-16 The Ledger Archive API RSS Weather Trader
Milepost
1108

TheForecast Post

A chronicle of American weather and climate  ·  Wednesday, 16 September 2026

The Ledger The Ledger MILEPOST 1101

The ledger, through September 16

Mean absolute temperature error runs 2.23°F at day 1 and 3.65°F at day 7, over 432,892 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 17–September 16, 2026.

LeadNDFDNBMpairs
Day 12.282.2366,811
Day 22.472.4264,554
Day 32.732.6362,055
Day 42.972.8559,700
Day 53.253.1257,305
Day 63.523.4154,894
Day 73.813.6542,677
Day 83.9524,896

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 33,175
August 17–September 16, 2026
day-3 mean absolute temperature error, NBM
Forecast Network verification ledger
2.63 °F of 30,832
August 17–September 16, 2026
day-5 mean absolute temperature error, NBM
Forecast Network verification ledger
3.12 °F of 28,508
August 17–September 16, 2026
day-7 mean absolute temperature error, NBM
Forecast Network verification ledger
3.65 °F of 26,095
August 17–September 16, 2026
day-1 mean absolute temperature error, NDFD
Forecast Network verification ledger
2.28 °F of 33,636
August 17–September 16, 2026
day-3 mean absolute temperature error, NDFD
Forecast Network verification ledger
2.73 °F of 31,223
August 17–September 16, 2026
day-5 mean absolute temperature error, NDFD
Forecast Network verification ledger
3.25 °F of 28,797
August 17–September 16, 2026
day-7 mean absolute temperature error, NDFD
Forecast Network verification ledger
3.81 °F of 16,582
August 17–September 16, 2026
Milepost
1101 · laid 2026-09-16T00:25:16Z
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
3a9c5eaa49d71ca116e765b937ea4376c7782206e1d60678ca8ebe53198ee440
Machine
JSON