The storms are on track to make landfall somewhere along the Gulf Coast within hours of each other.
Louisiana Gov. John Bel Edwards declared a state of emergency Friday ahead of the storms and on Saturday asked President Donald Trump to grant federal emergency status to the state.
On Tropical Storm Laura, the U.S. National Hurricane Center said, "At 500 PM AST [2100 UTC], the center of Tropical Storm Laura was located near latitude 18.0 North, longitude 68.1 West". There's also a Tropical Storm Watch for the Mississippi/Alabama border eastward to the Alabama/Florida border.
In Puerto Rico, the storm knocked down trees in the island's southern region and left more than 200,000 clients without power and more than 10,000 without water across the US territory. A tropical storm warning has been issued for Puerto Rico, which was expected to begin feeling Laura's effects by Saturday morning. Depending on how it holds together, its strength moving into the Gulf of Mexico will be greatly impacted.
Marco is continuing to strengthen and will likely be a hurricane soon.
Laura's threat to Alabama is less clear: Laura still has to cross over Hispaniola, Cuba and the Gulf of Mexico, so its track is more uncertain and its effect on Alabama also uncertain as of Saturday.
If Laura goes over land, Puerto Rico and the mountains of Haiti, the Dominican Republic and Cuba could tear it apart and not make it much of a threat to the mainland United States, meteorologists said.
The center of the storm was expected to move away from Puerto Rico as it headed for the Dominican Republic during the night.
Marco is forecast to produce heavy rains with possibility of flash flooding. The Air Force Reserve Hurricane Hunter aircraft dispatched to evaluate the storm measured sustained winds of 75 miles per hour. Now located off the west coast of Cuba, it is expected to head in a more northerly direction towards the Gulf Coast. A tropical storm warning included Lake Pontchartrain in Louisiana, and metropolitan New Orleans. Not too many changes within Marco or Laura this morning.
The tropical storms are forecast to meet in the Gulf on Tuesday.
Marco, which formed in the northwestern Caribbean, churned its way toward the Gulf of Mexico and was expected to move near the Yucatán Peninsula on Saturday, according to the hurricane center. The region along the Texas to MS coasts also accounts for 45% of total US petroleum refining capacity.
Tropical storm force winds extend 70 miles from the center.