Merrimack River - Black Rock Creek Entrance Rainfall ForecastUnited StatesMAEssex CountyMerrimack River - Black Rock Creek EntranceToday 18 Apr10%Sat 19 Apr25%Sun 20 Apr10%Mon 21 Apr5%Tue 22 Apr60%Wed 23 Apr10%Thu 24 Apr10%Merrimack River - Black Rock Creek Entrance rainfall forecast issued today at 3:04 pm. Next forecast at approx. 5:04 am.1-Day3-Day5-Day Graph Plots Open in Graphs Rainfall Probability Forecast NOAA Rain Today Real-Time Boston RadarNational SatelliteNational SynopticGet WillyWeather+ to remove ads