While you are at it, take a look at the Tropical Discussion link. They note this:
---
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT MON AUG 13 2007

SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE THAT A BROAD LOW PRESSURE AREA HAS FORMED IN THE SOUTHEASTERN GULF OF MEXICO ABOUT 90 MILES NORTH-NORTHEAST OF CANCUN MEXICO. UPPER-LEVEL WINDS ARE BECOMING MORE FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM...AND A TROPICAL DEPRESSION COULD FORM LATER TODAY OR TOMORROW AS THE LOW MOVES TO THE WEST-NORTHWEST AT 10 TO 15 MPH.
---

That storm could reach U.S. landfall before TS #4, which is still out in the Atlantic. That depends on the track, of course. It's worth noting that the weather station at Key West has been reporting record low minimum temperatures for a couple of weeks now. If that data is representative of warm water temperatures in the Gulf of Mexico, this little storm could pop into something big in a hurry.

http://www.ssd.noaa.gov/goes/east/gmex/ir2-l.jpg

E. Swanson