A nurse in the labor and delivery unit is attending to a client in labor. The nurse applies an external fetal monitor and toco transducer. The FHR is around 140/min. Contractions are every 8 min and 30 to 40 seconds in duration. The nurse performs a vaginal exam and finds the cervix is 2 cm dilated, 50% effaced, and the fetus is at a -2 station. Which stage and phase of labor is this client experiencing?