Determine the probability of precipitation (PoP) using the formula below and the following
PoP = (C * A) * 100 percent
Where C is the confidence that precipitation will occurs somewhere in the forecasted area, and A equals the percentage of the area that will receive measured precipitation if it occurs.
a. A forecaster expresses confidence that there is an 80 percent chance of precipitation in the forecasted area, and it is expected to produce measurable precipitation over 90 percent of the area.
b. A forecaster expresses confidence that there is a 20 percent chance of precipitation in the forecasted area, and it is expected to produce measurable precipitation over 10 percent of the area.