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 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).
During the past 30 days (July), the 2-meter temperature prediction verification for North America is best forecast by ECM ENS while the volatile GFS is last. The Artificial Intelligence Forecast System (AIFS) was 4th of 5 leading models.