A powerful storm is about to dump an entire month’s worth of rain on the Northeast, forecasters warn. The New York City metropolitan area can expect two to five inches (five to 13 centimeters) of rain over the next two days, with locally higher amounts possible. There is potential for life threatening flash flooding. Urban and poorly drained areas are particularly prone to flash flooding as pavement and other hard surfaces prevent water from soaking into the ground. Other major cities are facing a flash flood threat as well, including Boston, Massachusetts; Hartford, Connecticut; and Newark, New Jersey.