COLUMBUS, Ohio — Central Ohio is under a flood watch through 8 a.m. Monday as another round of rain moves into the region Sunday night, with additional flooding possible in parts of southern Ohio. Sunday began with partly sunny, humid conditions and temperatures expected to reach the low 80s. After sunset, a weak area of low pressure moving through the Ohio Valley is expected to pull a cold front across the state, bringing scattered showers and isolated thunderstorms. The heaviest pockets of rain are possible overnight, particularly in southern Ohio, where already-wet ground and rising waterways could increase the risk of flooding. Residents in flood-prone areas should monitor local alerts, avoid driving through flooded roads and be prepared for changing conditions. Rain will linger Monday morning, followed by mostly cloudy skies, scattered afternoon showers and temperatures in the 60s. Another round of rain is likely Monday night. Conditions are expected to briefly dry out Tuesday before rain returns Wednesday as another disturbance develops a wave of low pressure. High temperatures should remain between 65 and 70 degrees for much of the week, while morning lows fall into the 50s. Fall officially arrives at 8:05 p.m. Eastern time Tuesday. Drier, improving conditions are expected toward the end of the week as a storm system near the Atlantic coast moves farther away.