Rule of Thumb: Air that rises cools because it expands as it moves upward. (If the relative humidity is less than 100%, the cooling rate is about 5.5^oF/1000 feet).

Hence, one of the important ways in which a parcel of air can be cooled to its dew point temperature is when lifting or rising motion occurs.

Combining Rules of Thumb: if the air in two regions with high relative humidities is experiencing rising motion, and in one region the dewpoints are quite low, and in the other region they are quite high, in which of these two regions would you expect more precipitation?