@ZLabe i understand your point, but how do you express variability in a scenario like this, there is some natural variability in meteorological phenomena that should be expressed someway. I read some articles that refer to 3-sigma events, 5-sigma events... i assume that sigma is defined to some time span or something. Maybe the superposition of all curves defines an envolvent that act like a 2-sigma region, just thinking. Big fan of your plots.