Smaller watercourses like the Whitson River, Junction Creek, Romford Creek and many others will rise and some flooding may be experienced in low lying, known hazard areas.
The larger river systems in Greater Sudbury, namely the Vermilion, Wanapitei and Onaping, should also be closely monitored as levels and flows will increase.
Additional rainfall amounts of 15 to 20 millimetres are expected tonight, said the NDCA.
Tonight's rainfall could bring the total rainfall amounts in Greater Sudbury up to 50 millimetres by Tuesday morning. In the wake of the heavy rain, snow on Tuesday is forecast later in the day as colder air moves in.
Snowfall amounts are not expected to be significant.
The current forecast for later this week calls for temperatures below zero and limited precipitation, which will help slow the runoff and snowmelt.
The NDCA is in contact with the City of Greater Sudbury and will be communicating with other partners as required.
All residents in the City of Greater Sudbury are strongly advised to closely monitor the conditions overnight and into Tuesday. Public safety is the No. 1 priority. Creek and river banks will be very slippery and unsafe and must be avoided, especially by children who are on March break this week.
Any residents in the City of Greater Sudbury who may experience problems due to overland runoff or localized flooding are to call the City at 311, 24 hours a day.
The NDCA will update this message as required over the next number of days.