XX% chance of rain

[fishie1]

I was never exactly sure how to interpret this in a weather forecast. I kinda assumed it meant that there was an XX percent chance of rain, or the inverse, 100 - XX percent chance of no rain At a presentation by a NOAA official responsible for the WX forecasts and he explained that this actually means that XXpercent of the forecast area will receive rain in the forecast period. Not exactly the same thing since this way rain is a certainty. Just thought I would pass it along FWIW.

(I still don't believe their forecasts)

[troll]

Yes, it really is a coverage issue since the computer models don't take an exact spot and compute the odds. Forecasts vary from deadon to not even close. They are based on human interpretation of multiple computer models, nearby observations, sensor data, and mode.
It helps to know the general pattern in order to assess how accurate the forecast is likely to be. Some patterns are complex and are not well handled by the models while others are very stable and produce consistent results.

When deciding on an offshore trip, I look at tons of info including multiple forecast sources, forecaster discussions, wx models, etc.
I have always wished that for any given forecast, there would be some rating associated which gives a confidence factor. If you read the discussions you will see how much this can vary it is not included in the public forecasts.