From 10 days~, I see that wwl shows X% chance of precipitation, but on weatherbug site precipitation % is different.
Here is picture of current weather forecast. http://s13.postimg.org/i93j91glf/wwl_problem_12.jpg
Weather Watcher refactors the daily precipitation a bit, so it might not always match weatherbug.com. If the precipitation is different in the hourly forecast, then Weather Watcher shows the precipitation from the hourly forecast.
That explains why you’re seeing 10% in the daily forecast right now.