At midday, the 12Z GFS introduces a new tropical cyclone risk emerging in the vicinity of the Yucatan Peninsula and traveling northwestward toward the Houston area early-to-middle of next week.
A sharp upper trough delivers a cool burst to South America during the 6-10-day period. The risk of <32F is evident across Argentina with a slight risk as far north as Southeast Brazil.
The most destructive and life-threatening aspect of a tropical cyclone is flooding. Debby brings a gigantic area of excessive rainfall and attendant flash flood risk to the Southeast and East U.S. this week. 2-3 feet of rain is possible in parts of the Southeast U.S. as Debby stalls after moving inland.
The next issue is an evolving rainstorm in Florida and along the Atlantic Seaboard developing this weekend and lasting for much of next week. The culprit is Tropical Disturbance 97L, currently located over northwest Haiti, and given an 90% chance of tropical cyclone development after 48 hours (by NOAA/NHC).