Tropical storm conditions headed to Nicaragua, Costa Rica

Central America is bracing for tropical storm conditions.

The tropical system, now located off the northern coast of Colombia, has a 90% chance of developing into Tropical Storm Bonnie on Thursday as it approaches Nicaragua and Costa Rica.

It's expected to strengthen into a strong tropical storm before landfall Friday evening.

Heavy rainfall and gusty winds will be the biggest threat.

Hurricane watches are in effect for parts of Nicaragua's east coast and tropical storm warnings were issued for Colombia, Nicaragua, Costa Rica and the island of San Andres.

Early next week, the storm is expected re-emerge in the eastern Pacific and strengthen into a Category 1 hurricane off the coast of Mexico. Tropical storm watches were issued for parts of the west coasts of Nicaragua and Costa Rica.

Meanwhile, another tropical system is heading to coastal Texas and Louisiana, bringing heavy rain Thursday into Friday.

The heaviest rain will be focused along the Texas/Louisiana border. Areas between Houston and Lake Charles may see more than six inches of rain. Houston and Lake Charles can expect between two and four inches of rain.

The heaviest rain will happen Friday morning through the evening commute. Residents should be prepared for flash flooding.

ABC News' Riley Winch and Melissa Griffin contributed to this report.