My truck seems to have a bad habit of not wanting to start after a heavy rain....this is the second time after a heavy, overnight rainstorm that it won't start the following morning.

 

I bet if you open the hood you would find the plug wires wet from condensation.
As a test next time it is running and at night or dark out spray water on the plug wires, just a mist, and see if you see sparks jumping all over the place.
Don't forget the coil and wire too.
Dave - - - -

 

That is a high voltage ignition problem and in my experience is usually the coil.

 

And the spark is going to ground maybe at the coil, and if so why?
Bad plug wires because they either have high resistance and spark is finding the easiest way to ground or leaking out the wires to ground.
The water test should show this with a light show in the dark.
Dave - - - -

 

The first time I had this problem, I taped up the two lead wires to the coil with electrical tape and wrapped them lengthwise from the coil all the way to the split loom. I guess I need to double tape them and then tape them together and find some more split loom and cover them up then tape that.....

 

You are talking of the 2 low voltage wires right?
Now it's not good the they are exposed but being damp I don't think would be a cause of no start when damp.
Next time try a hair dryer on just them to see if it changes.
Dave - - - -

 

Cracks in the epoxy casing the coil. Every time I had this problem if the coil was heated with a hair dryer for 5 minutes the engine would fire up immediately confirming that the coil was the source of the problem.

 

Also should pull dist. cap to see if condensation inside.

 

Yea cracks in coil casing is not good.

Good call as I did not think of that but could be a cause.
Dave - - - -

 

I will check both the cap and coil. Hopefully this rain will let up by the time I knock off work...