Weather Underground Forecast for Thursday, May 23, 2013.

While tropical cyclone development is not anticipated in the tropical Atlantic Ocean on Thursday, areas of unsettled weather will develop in the Caribbean Sea and neighboring islands. High pressure north of the Caribbean Sea and a tropical wave crossing the southwestern corner of the basin toward southern Central America will maintain moderate to fresh trades across much of the Caribbean basin. Ample moisture and energy streaming across islands just north of the basin will create chances of light to moderate scattered showers and chances of thunderstorms in the Bahamas, Cuba, Hispaniola, Puerto Rico, and Jamaica. Meanwhile, more robust showers and with chances of thunderstorms are anticipated in the southwestern corner of the basin and across Panama, Costa Rica, and Nicaragua due to the approaching tropical wave and the proximity of the monsoon trough.

For South America, heavy rain, strong winds, and storms will continue across the northern tier of the continent as warm and humid flow streams across the region. To the south, rain and thunderstorm activity picks up in southeastern Brazil from areas near Sao Paulo through Rio de Janeiro, while lighter showers continue in parts of northern Santa Catarina and Paraguay. Further south, heavy precipitation drenching the southern third of Chile will begin to weaken as the strong low impacting the region moves eastward across southern Argentina toward the south Atlantic Ocean. Expect areas of light to moderate rain to accompany the low across the southern tail of Argentina.