Hurricane Harvey dropped tremendous amounts of rain over Texas and parts of Louisiana.  It’s estimated that values exceeded a 500 year storm in many locations.  A 500-year storm is one that has a 1 in 500 chance of occurrence in any given year. The Washington Post  has an interesting graphical story on what a 500-year storm would look like in five cities around the US, including Tampa and Miami FL.  While those are two of the most vulnerable cities in the Southeast right now, anywhere in the region could experience extreme flooding, particularly from a tropical system, although there have also been extreme rainfalls not associated with tropical weather such as the Atlanta GA floods of September 2009. You can see the story here.