this car howls when it starts up and goes away when it warms up

It's hard to guess what is causing the noise without hearing it first hand. My first guess would be a loose or contaminated fan belt. Look for a lose fan belt, wear, cracks or oil or anti freeze contamination on the fan belt. If it's not fan belt related a mechanic is going to have to test drive the car with you so you can point out the noise. Could it be a vacuum sound that would seal as the engine gets up to operating temperature?