Advice for Racing in the Rain

Avoid the painted lines on the roads. They are very slick when wet.

You may need to reduce the amount of time you spend aero (ease of braking)

plan on being conservative on the bike. As a runner you can make it all back up on the run

A few thoughts: 

Riding isn't much different.  Just give yourself more time to brake and take it easier in turns.  Avoid painted lines or metal grates/tracks which will get slick.

Definitely glasses with clear lenses.  Nothing worse than rain stinging your eyes.

If the temps are going to be cool, you'll probably want a rain jacket to put on in T1.  If it's warm enough though, skip it.  You're going to get wet.  No need to overheat too.

In transition, I like to use a large garbage bag to keep my things covered even if the stuff is going to get wet as soon as I get going.  I just sit my shoes, socks, hat, race belt, etc.  just inside the bag so it's just about as easy to grab as if it were sitting out on a towel.

I'm sure others will have some more in depth/detailed advice, but some of the things I do are:

Have your tires at a slightly lower pressure than normal to get more grip on the road, less chance of sliding/slipping over.

Be careful on tight corners, a bit less aggressive to make sure you don't slip(I'm not the best or most confident cornerer anyway).

With regard to glasses, I do wear mine in the rain. For me when I have problems it's not the rain falling on the outside of them, it's the increased moisture on the face evaporating onto the lenses and clouding them up. Of course mine are only cheap ones, you may not get this problem with higher quality glasses.

Also, on the bike I like to wear sunglasses, but will this even be possible with clear sunglasses if it's raining? 

Niiice!

I am liking the idea of the bins- never thought of that. At least I can start out with some dry gear. Thanks!

If your worried about handling.. i'd go with riding your road bike if you have one..

the benifits of aero will not be there if your on the brakes  all the time...

I don't have a road bike, so I have to make the tri bike work - or else I am stuck fat tiring on a mountain bike.