Jeff, I used to do a lot of rust busting on airplanes & missiles for the US Air Force. From what I can tell from your pictures, this rust is just a surface blemish and nothing to really worry about. You caught it early so you should be able to easily knock it off there by buffing it lightly with a bit of steel wool or some 400 - 600 grit sandpaper. After that you could touch it up with a covering of your choice: touch-up paint, clear lacquer, or maybe some green zinc chromate. Either way, make sure the metal can't interact with oxygen, re apply the weather strip and you should be better than new. Don't forget to check your driver's door too.

It might be a good thing to poke a few holes in the bottom of the weather strip to allow some place for water to drain as well.
Water + metal + oxygen = corrosion.