The ledger, through September 26
Mean absolute temperature error runs 2.23°F at day 1 and 3.85°F at day 7, over 513,115 settled forecast-observation pairs.
The LedgerSaturday, September 26, 2026The Ledger
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Milepost 1214
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 27–September 26, 2026.
| Lead | NDFD | NBM | pairs |
|---|---|---|---|
| Day 1 | 2.29 | 2.23 | 70,270 |
| Day 2 | 2.51 | 2.44 | 70,796 |
| Day 3 | 2.77 | 2.66 | 70,723 |
| Day 4 | 3.01 | 2.90 | 70,570 |
| Day 5 | 3.33 | 3.20 | 69,893 |
| Day 6 | 3.66 | 3.54 | 69,587 |
| Day 7 | 4.05 | 3.85 | 56,195 |
| Day 8 | — | 4.16 | 35,081 |
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 34,872 August 27–September 26, 2026 |
| day-3 mean absolute temperature error, NBM Forecast Network verification ledger |
2.66 °F | of 35,323 August 27–September 26, 2026 |
| day-5 mean absolute temperature error, NBM Forecast Network verification ledger |
3.2 °F | of 35,099 August 27–September 26, 2026 |
| day-7 mean absolute temperature error, NBM Forecast Network verification ledger |
3.85 °F | of 35,024 August 27–September 26, 2026 |
| day-1 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.29 °F | of 35,398 August 27–September 26, 2026 |
| day-3 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.77 °F | of 35,400 August 27–September 26, 2026 |
| day-5 mean absolute temperature error, NDFD Forecast Network verification ledger |
3.33 °F | of 34,794 August 27–September 26, 2026 |
| day-7 mean absolute temperature error, NDFD Forecast Network verification ledger |
4.05 °F | of 21,171 August 27–September 26, 2026 |
- Milepost
- 1214 · laid 2026-09-26T00:25:13Z
- 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.
- Stores
- /home/maue/forecastpoints/data/verify/2026-08.ndjson
/home/maue/forecastpoints/data/verify/2026-09.ndjson - Tagged
- I-500 Daily Weather · by rule, at build
- Digest
- 80012b09fc08f4407aea55cdb2580e3ec97a2530418e509b9c94dd8a666f9fde