At first I thought it must be weather station failure, but then I checked the radar streamlines and what ever it was shows up there as well. I can only assume it must have been a strong local thunderstorm type of event, but it lasted quite a few hours.
I think the Double Is. readings go along way to explaining why I couldn't get settled on the right gear yesterday. Kinda like science fiction leading science fact... When the meter is broken it creates erratic sailing conditions. Think we need some input from the gentlemen in Heavy Weather forum.
I would believe DI to be like that. From experience over the years it can turn nasty when it wants being exposed more than the other nearest places like rainbow beach.