A tornado watch is in effect for Brooklyn and Queens, along with much of the rest of southern New York and New York City.
According to the National Weather Service, there could be as much as one inch of rainfall very quickly over the course of the day Monday.
Areas that are prone to flooding or have poor drainage could also experience problems, the NOAA said.
The tornado watch is in effect until 5 p.m.
Under a tornado watch, conditions are right for the formation of tornadoes, though none have yet been spotted.