My air conditioning in my truck is making a constant howling noise, what is causing this?

My truck is a 95 Ford F150 xl 4.9L I6. A few minutes after I start my truck the A/C makes a constant howling noise when it is on the top fan speed and one lower. I don't know what is causing this.

Satan breathing down my neck that's why you hear that geeze!

So does it do it in vent and heat positions? If so, the fan is going.

A/C compressor could be about to fail or at least the bearings on the accessory drive belt pulley are.