Tropical Storm Isaac

Tropical Storm Isaac could reach Florida by early Monday. (National Hurricane Center / August 22, 2012)

As weather watchers eye Tropical Storm Isaac in the southeastern Caribbean, what is likely to become Tropical Storm Joyce isn't far behind it in the Atlantic.

We are still a few days away from an idea of where Isaac might impact the U.S., if at all. Meteorologists are debating whether the storm, currently expected to near south Florida by Monday morning, will track toward the Gulf of Mexico or up the East Coast. This is getting a lot of attention because of the Republican National Convention in Tampa next week.

It's also not clear, of course, if Maryland will see any of the storm, whether remnants and rain or something more like Irene coming up the coast.

Isaac could also continue in its current direction and head toward the Yucatan, or turn and head out to sea. Much of it depends on how the storm responds to nearby systems, such as a small trough of pressure over the Southeast, Weather Underground chief meteorologist Jeff Masters writes.

If the storm does eventually reach the East Coast, its rain could be welcome in many parts. AccuWeather blogger Henry Margusity points out a map of recent rainfall showing no need for it in the western Carolinas, where a tropical storm could mean major flooding, but elsewhere, it could help.

Baltimore is 8.5 inches short of normal rainfall so far this year, as measured at BWI Airport.

The National Hurricane Center gives another storm not far behind Isaac in the Atlantic a near-100 percent chance of forming into a tropical cyclone, which would earn it the name Joyce.

Have a weather question? E-mail me at sdance@baltsun.com or tweet to @MdWeather.