The ledger, through September 29
Mean absolute temperature error runs 2.23°F at day 1 and 3.86°F at day 7, over 514,579 settled forecast-observation pairs.
The LedgerTuesday, September 29, 2026The Ledger
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Milepost 1238
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 30–September 29, 2026.
| Lead | NDFD | NBM | pairs |
|---|---|---|---|
| Day 1 | 2.29 | 2.23 | 70,181 |
| Day 2 | 2.51 | 2.44 | 70,193 |
| Day 3 | 2.77 | 2.66 | 70,114 |
| Day 4 | 3.02 | 2.90 | 70,260 |
| Day 5 | 3.34 | 3.20 | 70,792 |
| Day 6 | 3.66 | 3.54 | 70,792 |
| Day 7 | 4.04 | 3.86 | 57,171 |
| Day 8 | — | 4.17 | 35,076 |
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 34,787 August 30–September 29, 2026 |
| day-3 mean absolute temperature error, NBM Forecast Network verification ledger |
2.66 °F | of 34,718 August 30–September 29, 2026 |
| day-5 mean absolute temperature error, NBM Forecast Network verification ledger |
3.2 °F | of 35,396 August 30–September 29, 2026 |
| day-7 mean absolute temperature error, NBM Forecast Network verification ledger |
3.86 °F | of 35,172 August 30–September 29, 2026 |
| day-1 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.29 °F | of 35,394 August 30–September 29, 2026 |
| day-3 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.77 °F | of 35,396 August 30–September 29, 2026 |
| day-5 mean absolute temperature error, NDFD Forecast Network verification ledger |
3.34 °F | of 35,396 August 30–September 29, 2026 |
| day-7 mean absolute temperature error, NDFD Forecast Network verification ledger |
4.04 °F | of 21,999 August 30–September 29, 2026 |
- Milepost
- 1238 · laid 2026-09-29T00:25:14Z
- 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.
- 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
- 29bf2ad37a714f2997c5ea066bad65aa18bbc54ee19f37beadc21a7644fcb4e3