Jeff,
The weather forecast is biased toward forecasting more rain than will actually happen.

The main reason: people become angry with the weather forecasters when an event is rained out but rain not forecasted.

If rain is forecasted but no rain, most people are happy. Most are ignorant of farming and ponds and would rather it rarely rained. They like to live in the desert, but like to enjoy cheap water.

We pond owners and farmers are the exception.