I'm hitting the lake Sunday in the trusty aluminum tracker. Any guesses on what the rain will do to the bite?

I'm curious about this as well. Will the rain push water temps up and make fish more active?

Its all about the barometer, when a storm pushes in its is low pressure which helps fishing generally. Once the storm moves out a high pressure front usually settles in which hinders fishing generally.

How long does this process take? Let's say we should expect low pressure Friday, rain Saturday and higher pressure to be here on Sunday? Or will that not take place until Monday?

Usually the high pressure follows a real windy day. That sequence is right on, the low pressure leaves with the rain.

it can be a matter of hours not days...

Yeah depends on how fast the system is moving.