No PV forecast modelled snow lying on the modules, so after a snowfall the
optimizer planned with PV that never came. The local Open-Meteo/pvlib
backend can now reduce the forecast by the snow coverage (opt-in via
pvforecast.akkudoktor.snow_enabled):
- Request hourly snowfall and snow depth with the weather and run the NREL
snow coverage model (pvlib.snow) per plane.
- Correct the coverage with measured PV production: production above the
model clears it at once; low production raises it only while snow is
plausible, so curtailment and inverter outages are not learned as snow.
Persisting snow damps the slide rate, fading with
snow_feedback_memory_hours.
- Rebuild the coverage from snow_lookback_days on every update instead of
storing state.
- Exclude intervals with possible snow from the calibration fit.
- Warn when PV meter readings are missing or stale; ignore impossible meter
jumps.
_plane_power keeps its two-value signature (used by the adaptive provider in
#1422); the irradiance comes from the new _plane_power_and_poa.
Tests replay real February 2026 data from one plant (snow on 02-19/20).
Signed-off-by: SchaafAlexander <86607129+SchaafAlexander@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
