This is a QPF map from the NOAA site and it is showing a whole heck of a lot of rain that is forecast to fall in a 4-5 day timeframe, starting Tuesday and ending Saturday. In total, in the 4-5 day period, parts of New England, especially southern New England, could be seeing rainfall amounts on the order of 4-6". A half-foot of rain could pose a risk of flooding.
It will not rain straight on through the period, but there will be bouts of showers and heavy thunderstorms, that will have this rain fall in a short time period. We will likely see an inch of rain at a time. The first day with a chance of showers will be later on tomorrow night, but it is a small chance and most places will be dry during the day tomorrow. A few evening showers and thunderstorms, especially in CT and RI will be possible, I would say a 25-40 percent chance. Then Wednesday will be a rather rainy day with showers and thunderstorms, locally heavy, pretty much all day which will yield quite a bit of rainfall before a semi dry day on Thursday, yielding another pretty wet Friday and Friday night with more heavy rains and thunderstorms, but there will be completely dry periods on both Wednesday and Friday. It will not be raining the entire day. It will be very wet though and during peak rainfall, street and urban flooding will be possible. It will also be extremely humid as well after today with dewpoints getting back to the oppressive levels by Wednesday through Friday and Saturday. Dewpoints will likely be in the 68-72 degree range. It will feel gross.