ES250,Power steering stiff when cold

On cold days, my power steering is extremely stiff if the engine is cold. On top of this, it feels like the steering wheel is jolting trough a cold turn. However, this stops after completing a turn all the way to the left and to the right and after the engine has warmed up completely. Referring back to the jolting of the steering wheel, you can hear the belt squeak on each jolt as it's being turned. There's no issue after the engine has warmed up and made a couple turns on the steering wheel. Would this be a sign of a bad power steering pump? I notice a jolting steering wheel when goin