Precipitation-probability without precipitation value

[delphir-com]

For some reason hours with precipitation-probability do not have the actual precipitation value... looks like "rain" values are completely missing.

[patrick-zippenfenig]

Precipitation probability is calculated using ensemble models from many weather forecast runs. The actual (deterministic) precipitation amount is only based on a control weather forecast run. It is correct, that precipitation probability can be very high without actual precipitation being forecast.

That being said, the current implementation of precipitation probability is not optimal and only using global weather models. With the recent release of the Ensemble API more regional ensemble model are available, but this information is not yet used for precipitation probability.

Precipitation should be the sum of rain, showers and snowfall. In your screenshot your disabled showers. Was showers showing some values?

[delphir-com]

showers == precipitation in my case, I was just expecting that "high probability" must be accompanied with whatever precipitation values... and by looking at other weather-services - they are "promising" rain around the same time where probability is high but no precipitation returned... so my assumption was that "rain" values are missing from the results :D

[patrick-zippenfenig]

Precipitation probabilities are now calculated for all ensemble models and are used by the regular weather API. This significantly improves consistency between precipitation amount and probability. Of course it is still possible that both show conflicting predictions which is the nature of probabilistic forecasts.