In talking with or weather team here's the best way to describe it to
you. Isolated showers are just that, they are isolated to a particular
area. That means there is a good chance a majority of the viewing area
will stay dry.
As for scattered showers, it's probably a good idea to keep the umbrella
handy. When scattered showers are in the forecast it simply means there
is a chance of showers for a larger portion of our coverage area and you
could just see a shower where you are, but not 20 minutes down the road.