Relies on calibration of subjective forecasts of probability.
Need probability of precipitation forecast.
Uses conditional exceedence fractiles:
- The X50, or amount where there is an equal chance of getting more or less precipitation that that number
- the X25, amount the forecaster thinks there is a 25% percent chance of exceeding that value.
- Can than use curve to set probabilities for any amount.
Used quasi-operationally at the PIT WFO