Living beside a river, you soon learn to not be overly surprised should you wake at 6:00 a.m., totter into the great room and glance out at the stream flowing past the cottage, and discover the water level had risen a half-dozen feet during the night—in spite of the fact you hadn't witnessed a single raindrop during the previous 36 hours.
Water, of course, flows downhill. A simple matter of gravity. Therefore, the state of the river's water level in your bailiwick at any given time is a direct but delayed result of weather conditions upstream. How much rain fell and how far are only two of the factors which determines when such run-off water arrives at your place. Additionally, how quickly the rain came down, and how widespread the rainfall was upon the watershed area above you, plus things such as local topography, percolation rate, cover vegetation, and existing groundwater saturation also influence run-off and flow rate.
Too many and too variable to master well enough that you can hone your expectations down to anything precise enough to be called a schedule. An educated guess with plenty of wiggle room is about the best you can do.
However, when you fail to pay even cursory attention to evening weather reports because you were off tromping around under mostly sunny skies at a nearby prairie, photographing things like sweet-scented milkweed, bumblebees on lavender bergamot, and a male redwing blackbird who got all territorial and insisted on screeching at you from atop a swaying stem…well, the unanticipated dawn sight of high, muddy water just beyond the edge of the deck can prove a bit startling. Especially if you hadn't had your coffee.




