Florida Governor Rick Scott has issued a state of emergency as tropical storm Erika approaches the state after leaving a trail of death and destruction on the eastern Caribbean island of Dominica.

Scott made the declaration Friday shortly after forecasters said the storm is projected to strike the southern tip of the state and then travel northward.

The order ahead of time gives Scott and other state officials the upperhand to prepare for the storm. It calls for the activation of the National Guard and gives emergency crews and vehicles the ability to move freely throughout the state.

Photos and videos posted on social media showed floodwaters inundating streets and causing buildings to collapse in Dominica.

The Antigua Weather Service said that up to 15 inches of rain fell there between late Wednesday and early Thursday.

At least 20 people were reported dead and another 31 missing, authorities said.

President Barack Obama was informed about disaster preparations, according to the White House.

The Federal Emergency Management Agency has dispatched assistance teams to Puerto Rico, St. Croix and St. Thomas and "they continue to back response activities to ensure that there are no unmet needs on those islands," White House Press Secretary Josh Earnest said on Friday.

The agency has also set up relief supplies in the state of Georgia.

Erika will likely remain at tropical storm strength as it nears Florida, according to the National Hurricane Center.  However, the center said Erika is expected to weaken and could even dissipate in the next 12 to 24 hours.

"If the center of Erika survives the mountainous terrain of Hispaniola (the island which is home to the Dominican Republic and Haiti) it should slowly reorganize back into a tropical storm this weekend just northeast of Cuba," AccuWeather hurricane expert Dan Kottlowski said.

"If Erika does not survive the interaction with Hispaniola, it may never reorganize into a coherent tropical storm again and impact on Florida would be reduced," he added.

US Drought Monitor said that some rain would be welcome in South Florida, where some areas are in severe or extreme drought. However, that may not be the case elsewhere in Florida.