WeatherBlend

Multi-model forecast blending for Sennen, Cornwall

Rain models

Per-station P(wet ≥ 0.1 mm/h) — 3a (lean) + 3c (rich), Brier, lower better. Plus per-station rainfall amount (mm/h) — 3f distributional, CRPS, lower better. Δ vs best single NWP — negative = blend wins.

Precipitation — St Erth

Phase 3c · v2026-06-15_170413_phase3c Δ -0.002 vs prev train

Rich P(wet) classifier, 101 features — rich surface (humidity/dew-depression/cloud/EA persistence) + the multi-level pressure (upper-air) block (850/700/500 hPa temps, heights, winds, RH850 across 4 exact NWPs, lead-matched by a leak-free backward ASOF). UA added in-place 2026-06-02 (−3.7%→−6.8% Brier across 24→72h). Trained 2026-06-15. Metric: Test Brier.

Lead Blend Best single Δ vs best
+24h 0.086 precip_mf (0.145) -40.5%
+48h 0.098 precip_ukmo (0.235) -58.4%
+72h 0.106 precip_ukmo (0.265) -60.0%
+96h 0.112 precip_icon (0.248) -55.0%
+120h 0.121 precip_ukmo (0.368) -67.2%
Verify history (2 runs)

Mon + Thu rolling Brier. Per-lead cells turn red when the rolling metric breaches the lead-specific drift threshold; check the verify report for the per-cell breakdown. Version column names the trained model — a fresh champion takes ~5-9d to show.

Run (UTC) Version N +12h+24h+48h+72h+96h+120h
v2026-06-07_145447_phase3c
v2026-06-10_180626_phase3c		 304 0.035
mf: 0.030		0.014
mf: 0.014		0.009
ecmwf: 0.000		0.010
gfs: 0.000		0.040
gem: 0.041		0.007
gfs: 0.000
v2026-06-07_145447_phase3c
v2026-06-10_180626_phase3c		 178 0.258
icon: 0.300		0.120
mf: 0.174		0.155
gem: 0.182		0.255
gfs: 0.300		——

Phase 3a · v2026-06-14_153455 Δ -0.007 vs prev train

Lean P(wet) classifier, 27 features. Trained 2026-06-14. Metric: Test Brier.

Lead Blend Best single Δ vs best
+24h 0.089 precip_mf (0.152) -41.7%
+48h 0.100 precip_icon (0.204) -51.1%
+72h 0.109 precip_icon (0.203) -46.3%
+96h 0.112 precip_icon (0.251) -55.2%
+120h 0.121 precip_gfs (0.216) -43.9%
Verify history (2 runs)

Mon + Thu rolling Brier. Per-lead cells turn red when the rolling metric breaches the lead-specific drift threshold; check the verify report for the per-cell breakdown. Version column names the trained model — a fresh champion takes ~5-9d to show.

Run (UTC) Version N +24h+48h+72h+96h+120h
v2026-06-07_145346 552 0.060
mf: 0.092		0.060
gem: 0.081		0.055
gfs: 0.070		0.042
gem: 0.041		0.005
gfs: 0.000
v2026-06-07_145346 178 0.123
mf: 0.174		0.156
gem: 0.182		0.246
gfs: 0.300		——

Precipitation — St Ives Towednack

Phase 3c · v2026-06-15_170404_phase3c Δ -0.002 vs prev train

Rich P(wet) classifier, 101 features — rich surface (humidity/dew-depression/cloud/EA persistence) + the multi-level pressure (upper-air) block (850/700/500 hPa temps, heights, winds, RH850 across 4 exact NWPs, lead-matched by a leak-free backward ASOF). UA added in-place 2026-06-02 (−3.7%→−6.8% Brier across 24→72h). Trained 2026-06-15. Metric: Test Brier.

Lead Blend Best single Δ vs best
+24h 0.099 precip_mf (0.202) -51.0%
+48h 0.108 precip_ukmo (0.249) -56.8%
+72h 0.121 precip_ukmo (0.259) -53.2%
+96h 0.125 precip_icon (0.257) -51.1%
+120h 0.137 precip_ukmo (0.369) -62.8%
Verify history (2 runs)

Mon + Thu rolling Brier. Per-lead cells turn red when the rolling metric breaches the lead-specific drift threshold; check the verify report for the per-cell breakdown. Version column names the trained model — a fresh champion takes ~5-9d to show.

Run (UTC) Version N +12h+24h+48h+72h+96h+120h
v2026-06-07_145426_phase3c
v2026-06-10_180559_phase3c		 304 0.133
mf: 0.168		0.200
aifs: 0.226		0.131
aifs: 0.143		0.104
gfs: 0.100		0.161
gem: 0.242		0.168
jma: 0.205
v2026-06-07_145426_phase3c
v2026-06-10_180559_phase3c		 178 0.222
icon: 0.300		0.148
icon: 0.236		0.187
ukmo: 0.250		0.251
icon: 0.300		——

Phase 3a · v2026-06-14_153430 Δ -0.006 vs prev train

Lean P(wet) classifier, 27 features. Trained 2026-06-14. Metric: Test Brier.

Lead Blend Best single Δ vs best
+24h 0.101 precip_mf (0.215) -53.1%
+48h 0.110 precip_mf (0.249) -55.8%
+72h 0.124 precip_mf (0.261) -52.6%
+96h 0.127 precip_icon (0.258) -50.7%
+120h 0.137 precip_gfs (0.231) -40.7%
Verify history (2 runs)

Mon + Thu rolling Brier. Per-lead cells turn red when the rolling metric breaches the lead-specific drift threshold; check the verify report for the per-cell breakdown. Version column names the trained model — a fresh champion takes ~5-9d to show.

Run (UTC) Version N +24h+48h+72h+96h+120h
v2026-06-07_145327 552 0.130
mf: 0.217		0.127
gfs: 0.209		0.147
gfs: 0.220		0.186
gem: 0.242		0.172
jma: 0.205
v2026-06-07_145327 178 0.154
icon: 0.236		0.193
gem: 0.273		0.236
icon: 0.300		——

Precipitation — Trengwainton

Phase 3c · v2026-06-15_170358_phase3c Δ -0.001 vs prev train

Rich P(wet) classifier, 101 features — rich surface (humidity/dew-depression/cloud/EA persistence) + the multi-level pressure (upper-air) block (850/700/500 hPa temps, heights, winds, RH850 across 4 exact NWPs, lead-matched by a leak-free backward ASOF). UA added in-place 2026-06-02 (−3.7%→−6.8% Brier across 24→72h). Trained 2026-06-15. Metric: Test Brier.

Lead Blend Best single Δ vs best
+24h 0.088 precip_mf (0.168) -47.6%
+48h 0.095 precip_ukmo (0.250) -61.9%
+72h 0.107 precip_ukmo (0.273) -60.8%
+96h 0.113 precip_ukmo (0.310) -63.6%
+120h 0.122 precip_ukmo (0.366) -66.6%
Verify history (2 runs)

Mon + Thu rolling Brier. Per-lead cells turn red when the rolling metric breaches the lead-specific drift threshold; check the verify report for the per-cell breakdown. Version column names the trained model — a fresh champion takes ~5-9d to show.

Run (UTC) Version N +12h+24h+48h+72h+96h+120h
v2026-06-07_145406_phase3c
v2026-06-10_180531_phase3c		 304 0.078
ecmwf: 0.092		0.073
ecmwf: 0.096		0.082
ecmwf: 0.095		0.102
gfs: 0.100		0.089
gem: 0.119		0.071
gfs: 0.091
v2026-06-07_145406_phase3c
v2026-06-10_180531_phase3c		 192 0.330
mf: 0.300		0.157
ecmwf: 0.245		0.223
ukmo: 0.295		0.402
jma: 0.300		——

Phase 3a · v2026-06-14_153405 Δ -0.006 vs prev train

Lean P(wet) classifier, 27 features. Trained 2026-06-14. Metric: Test Brier.

Lead Blend Best single Δ vs best
+24h 0.091 precip_mf (0.179) -49.3%
+48h 0.099 precip_icon (0.202) -51.3%
+72h 0.109 precip_icon (0.210) -48.0%
+96h 0.113 precip_icon (0.251) -55.0%
+120h 0.123 precip_gfs (0.211) -41.9%
Verify history (2 runs)

Mon + Thu rolling Brier. Per-lead cells turn red when the rolling metric breaches the lead-specific drift threshold; check the verify report for the per-cell breakdown. Version column names the trained model — a fresh champion takes ~5-9d to show.

Run (UTC) Version N +24h+48h+72h+96h+120h
v2026-06-07_145307 566 0.113
ecmwf: 0.163		0.115
gem: 0.173		0.109
mf: 0.140		0.095
gem: 0.119		0.075
gfs: 0.091
v2026-06-07_145307 192 0.157
ecmwf: 0.245		0.221
gem: 0.318		0.402
jma: 0.300		——