1997 Ford Ranger Squealing noise under the hood

My ranger starts fine and sounds normal while the engine is cold, but when the engine starts to warm up I hear a chirp chirp chirp and then a full on squeal. I am not sure, but it may stop when I get to speeds of 30mph or above. I do know that after I have driven higher speeds and slow down that the noise has seemed to lessen, but promptly returns after a minute. I recently had the serpentine belt replaced, the slave cylinder replaced, and the ignition coil replaced; but the noise did not appear until at least a few months after they were replaced. Any ideas?