WeatherBlend

Multi-model forecast blending for Bonehill Rocks, Dartmoor

Precipitation — P(wet ≥ 0.1 mm/h)

Per-station hourly occurrence blender. EA Hydrology gauges as truth; LightGBM per lead-time bucket. Three blenders are active per station — Phase 3a (lean, 27 features) as the original champion, Phase 3a_isotonic (3a's output re-mapped by a per-lead pool-adjacent-violators isotonic regression fit on the validation slice), and Phase 3c (rich, 55 features) as the feature-richness challenger with per-model humidity, surface pressure, and EA trailing-rainfall persistence. All three produce predictions every cycle; charts below are grouped by phase so differences between feature richness and post-hoc calibration are visible at a glance.

Bellever Dartmoor

Next 2h at +24h (Phase 3c): mean P(wet) = 0.02, peak 0.04 at 2026-04-25 05:00Z.

Phase 3a — lean (27 features)

Per-model precip + precip-prob, spread stats, covariate means, calendar encodings. Original champion.

P(wet ≥ 0.1 mm/h) — Bellever Dartmoor — Phase 3a0.280.220.170.110.05-0.0004-24 07Z04-24 21Z04-25 11Z04-26 01Z04-26 15Z04-27 05ZValid time (UTC)ProbabilityBlend +24hBlend +48hBlend +72hClimatology

Phase 3c — rich (55 features)

Lean + 18 per-model humidity (dew/RH/depression) + 6 per-model surface pressure + 4 EA trailing-rainfall persistence features. Challenger.

P(wet ≥ 0.1 mm/h) — Bellever Dartmoor — Phase 3c0.280.220.170.110.05-0.0004-24 15Z04-25 03Z04-25 15Z04-26 04Z04-26 16Z04-27 05ZValid time (UTC)ProbabilityBlend +24hBlend +48hBlend +72hClimatology

Three-way comparison — +24h lead

3a (raw), 3a_isotonic (calibrated), and 3c (rich) on the same axis. If 3a_isotonic tracks 3c, calibration alone did the work the extra features were supposed to do.

3a vs 3a_isotonic vs 3c — Bellever Dartmoor — +24h0.040.030.030.020.010.0104-24 07Z04-24 11Z04-24 15Z04-24 20Z04-25 00Z04-25 05ZValid time (UTC)ProbabilityPhase 3a (champion)Phase 3c (challenger)

Dartmoor Nr Hexworthy

Next 2h at +24h (Phase 3c): mean P(wet) = 0.01, peak 0.01 at 2026-04-24 15:00Z.

Phase 3c — rich (55 features)

Lean + 18 per-model humidity (dew/RH/depression) + 6 per-model surface pressure + 4 EA trailing-rainfall persistence features. Challenger.

P(wet ≥ 0.1 mm/h) — Dartmoor Nr Hexworthy — Phase 3c0.240.200.150.100.050.0004-24 15Z04-25 03Z04-25 15Z04-26 04Z04-26 16Z04-27 05ZValid time (UTC)ProbabilityBlend +24hBlend +48hBlend +72hClimatology

Princetown

Next 2h at +24h (Phase 3c): mean P(wet) = 0.02, peak 0.02 at 2026-04-25 05:00Z.

Phase 3a — lean (27 features)

Per-model precip + precip-prob, spread stats, covariate means, calendar encodings. Original champion.

P(wet ≥ 0.1 mm/h) — Princetown — Phase 3a0.240.200.150.100.050.0004-24 07Z04-24 21Z04-25 11Z04-26 01Z04-26 15Z04-27 05ZValid time (UTC)ProbabilityBlend +24hBlend +48hBlend +72hClimatology

Phase 3c — rich (55 features)

Lean + 18 per-model humidity (dew/RH/depression) + 6 per-model surface pressure + 4 EA trailing-rainfall persistence features. Challenger.

P(wet ≥ 0.1 mm/h) — Princetown — Phase 3c0.230.180.140.090.050.0004-24 15Z04-25 03Z04-25 15Z04-26 04Z04-26 16Z04-27 05ZValid time (UTC)ProbabilityBlend +24hBlend +48hBlend +72hClimatology

Three-way comparison — +24h lead

3a (raw), 3a_isotonic (calibrated), and 3c (rich) on the same axis. If 3a_isotonic tracks 3c, calibration alone did the work the extra features were supposed to do.

3a vs 3a_isotonic vs 3c — Princetown — +24h0.020.020.020.020.010.0104-24 07Z04-24 11Z04-24 15Z04-24 20Z04-25 00Z04-25 05ZValid time (UTC)ProbabilityPhase 3a (champion)Phase 3c (challenger)

Hourly detail (next 96h)

Station Phase Valid time Lead P(wet) Climatology Version
Bellever Dartmoor 3a 24h 0.01 0.27 v2026-04-23_071842
Bellever Dartmoor 3a 24h 0.01 0.22 v2026-04-23_071842
Bellever Dartmoor 3c 24h 0.01 0.22 v2026-04-23_154405_phase3c
Bellever Dartmoor 3a 24h 0.02 0.27 v2026-04-23_071842
Bellever Dartmoor 3c 24h 0.04 0.27 v2026-04-23_154405_phase3c
Bellever Dartmoor 3a 48h 0.02 0.27 v2026-04-23_071842
Bellever Dartmoor 3a 48h 0.01 0.22 v2026-04-23_071842
Bellever Dartmoor 3c 48h 0.02 0.22 v2026-04-23_154405_phase3c
Bellever Dartmoor 3a 48h 0.03 0.27 v2026-04-23_071842
Bellever Dartmoor 3c 48h 0.03 0.27 v2026-04-23_154405_phase3c
Bellever Dartmoor 3a 72h 0.06 0.27 v2026-04-23_071842
Bellever Dartmoor 3a 72h 0.02 0.22 v2026-04-23_071842
Bellever Dartmoor 3c 72h 0.04 0.22 v2026-04-23_154405_phase3c
Bellever Dartmoor 3a 72h 0.06 0.27 v2026-04-23_071842
Bellever Dartmoor 3c 72h 0.03 0.27 v2026-04-23_154405_phase3c
Dartmoor Nr Hexworthy 3c 24h 0.01 0.23 v2026-04-23_154459_phase3c
Dartmoor Nr Hexworthy 3c 24h 0.01 0.23 v2026-04-23_154459_phase3c
Dartmoor Nr Hexworthy 3c 48h 0.02 0.23 v2026-04-23_154459_phase3c
Dartmoor Nr Hexworthy 3c 48h 0.03 0.23 v2026-04-23_154459_phase3c
Dartmoor Nr Hexworthy 3c 72h 0.03 0.23 v2026-04-23_154459_phase3c
Dartmoor Nr Hexworthy 3c 72h 0.04 0.23 v2026-04-23_154459_phase3c
Princetown 3a 24h 0.02 0.23 v2026-04-23_071934
Princetown 3a 24h 0.02 0.22 v2026-04-23_071934
Princetown 3c 24h 0.01 0.22 v2026-04-23_154433_phase3c
Princetown 3a 24h 0.02 0.18 v2026-04-23_071934
Princetown 3c 24h 0.02 0.18 v2026-04-23_154433_phase3c
Princetown 3a 48h 0.02 0.23 v2026-04-23_071934
Princetown 3a 48h 0.01 0.22 v2026-04-23_071934
Princetown 3c 48h 0.02 0.22 v2026-04-23_154433_phase3c
Princetown 3a 48h 0.02 0.18 v2026-04-23_071934
Princetown 3c 48h 0.02 0.18 v2026-04-23_154433_phase3c
Princetown 3a 72h 0.04 0.23 v2026-04-23_071934
Princetown 3a 72h 0.02 0.22 v2026-04-23_071934
Princetown 3c 72h 0.03 0.22 v2026-04-23_154433_phase3c
Princetown 3a 72h 0.02 0.18 v2026-04-23_071934
Princetown 3c 72h 0.03 0.18 v2026-04-23_154433_phase3c