Ever wonder what the difference is between isolated and scattered thunderstorms in a weather forecast?
Well, it depends who you ask. The most popular answer, purportedly endorsed by the National Weather Service, is that its a matter of the probability of the thunderstorms occurrence. (See here and here.) But the WGN Weather Center says instead that its a matter of the likely geographical extent of such storms.
In either case, isolated apparently portends less soakage than scattered.
Reminds me of this from Steven Landsburg:
http://www.thebigquestions.com/2010/04/21/partly-unclear/