. The skydiver will soon open her parachute. How will her velocity change when
the parachute first opens?

How will her velocity change when  does parachute first open?

The skydiver's weight is balanced by the air resistance. There is no resultant force and the skydiver reaches terminal velocity. When the parachute opens, the air resistance increases. The skydiver slows down until a new, lower terminal velocity is reached.

When a skydiver opens their parachute, they accelerate upwards. This is not the same as saying the move upwards. Acceleration is a change in velocity. They keep feeling an upward force (while moving downward) that slows them until they get to a new terminal velocity.

What force changes when a parachute opens?

An open parachute increases the cross-sectional area of the falling skydiver and thus increases the amount of air resistance which he encounters (as observed in the animation below). Once the parachute is opened, the air resistance overwhelms the downward force of gravity.

What happens if you open the parachute too early?

You are likely to drift off the drop zone. The winds can be pretty heavy at high altitudes, and unless you steer continuously they may blow you off-course. Needless to say, the refrigeration effect of the wind and slipstream will make you feel even colder than the mere altitude. Your landing is likely to be rough.