Except for a brief period for college, I've spent all of my life living close enough to the Texas coast for Hurricane Season to be an issue, but it was only recently that I began to notice the forecasters mentioning "tropical waves." What the heck are those?
Turns out that they are baby hurricanes (although not all of them grow up to be hurricanes). According to The Weather Channel, a tropical wave is "[a] low pressure trough of persisting winds that blow from east to west." This can develop into a "tropical disturbance," which may then grow to a "tropical depression." A tropical depression can grow up to be a "tropical storm," which in turn can grow up to be a "hurricane."
All of these are "tropical cyclones." A tropical wave can morph into a hurricane in about five days.
If you want a satellite view of these systems, check out the CIMSS website: http://cimss.ssec.wisc.edu/tropic2/
So, keep an eye on those tropical waves, you never know what they might grow up to be.