We’re surrounded by this colorless, odorless, transparent thing: our atmosphere. It’s full of many components suspended in different ratios depending on where or when you measure.
With me so far? This won’t take long.
Depending on temperature the atmosphere has a finite limit of how much water vapor it can hold. Too much and it becomes saturated. As long as the atmosphere is below saturation (aka 100% humidity), most of the water vapor entering it will be held.
Tonight it’s snowing like crazy ‘over’ all of Connecticut. At the same time it’s only the shoreline where we’ve reached saturation.
At Bradley that overhead snow is evaporating… disappearing as water vapor into the clouds… and hasn’t yet reached the ground.
Think of a sponge. If you pour water into it the sponge will absorb it… until it can’t. That’s saturation. After that everything you pour in will pass right through!
On the shoreline this manifested itself by the very rapid transition from light to heavy snow.