I've searched and searched on the boards for the answer to my question but to no avail. I'm sure someone will be able to point me to one or help me out. For some reason, as of lately, my buttercream is 'bulging' between my layers. As much as I smooth it, I end up with a ripple. Why? What is causing that? The only thing I can think that has changed is the heat. If you can help me out I would REALLY appreciate it! THanks so much.
Kim

How soon after you bake your cakes are you decorating?

Cakes might need to settle longer.

You need a stiffer butter cream between your layers. You also need to let your cakes settle for a few hours before decorating.

Yep, Stiff buttercream dam and let settle a little longer.

Hmm. Stiff buttercream must be my issue because most of my cakes are coming from the fridge (where I let them thaw from freezer for 12-24 hours). I use a mixture of butter and shortening in my buttercream, is it possible for the butter to be 'melting'? Should I simply add less water?

I use butter and hi ratio shortening in my butter cream. When I make my batch of butter cream instead of adding 1/3 cup liquid I start with 1/4 cup. Then once I am done filling my cakes I add additional liquid until I get the correct consistency of butter cream.

Fantastic tip sweettreat101. I'll be sure to try that.

Thanks to everyone who posted!!!!