Hurricane Harvey plodded toward a wet exit Friday, leaving more misery in its wake with intense rain and flooding predicted far north as Kentucky.

Poised to take Harvey's place, Hurricane Irma spun up from a tropical storm to a "dangerous" Category 3 hurricane as it traveled across the Atlantic Ocean. Irma could reach Category 4 with sustained winds above 130 mph as it edges toward the Lesser Anteilles, north of South America, early next week.

"If Irma builds to a Category 4, and then hits the U.S. mainland, it will be the first time in more than 100 years the U.S. has been hit by two Category 4 hurricanes in the same year," said Evan Myers, senior Accuweather meteorologist.

At 11 a.m. Friday, Irma had sustained winds of 110 mph with stronger gusts, according to the National Weather Service. The storm was moving west-northwest at 13 mph, but a turn to the west-southwest was expected on Saturday, the service said.

"Fluctuations in strength, up or down, are possible during the next few days, but Irma is expected to remain a powerful hurricane through the weekend," the service said.

Irma's career path isn't set yet, potentially heading either north or south of Puerto Rico. There is no projected landfall yet.

"There is the potential for Irma to ramp up to an even more powerful hurricane in the coming days," according to Dan Kottlowski, an AccuWeather hurricane expert.

Accuweather urged officials in the eastern Caribbean to monitor "this evolving and dangerous hurricane.

In the meantime, Harvey's unrelenting rain still commands the spotlight even as it dissipates into a tropical depression.

Flooding is expected to continue in Texas for days, and in spots up the lower Mississippi River valley to the Ohio River valley as the storm crawls north and east.

Four to 8 inches of rain, with a serious threat of flash flooding, are projected across the Tennessee Valley and West Virginia, as water rushes from higher elevations to low-lying areas.

"As the rains move into the northeast, residents of these areas should remain extremely vigilant," Myers said.

The Nashville area, which got up to 10 inches of rain in the past day, closed schools Friday. The river levels do not come close to the historic 2010 flood, which caused over $2 billion in property damage and claimed the lives of 11 people in Davidson County.

Richard Williams woke up to find water already knee deep in the Chestnut Flats Apartments, when a neighbor pounded on his door at 11:30 p.m. Thursday.

All 13 residents of the complex were evacuated to a Red Cross shelter. About 50 people evacuated from flooding across the city.

The National Weather Service in Louisville issued a flash-flood warning for that area Friday until noon.

After dumping a record nearly 52 inches of rain on Houston, Harvey has already killed at least 39 people. Search and rescue efforts continue block by block in Houston.

Building temporary housing and repairing damaged structures is a process that officials warn will prove frustrating.

More than 325,000 people had applied for federal disaster assistance because of Harvey by Thursday morning, with $57 million paid out by that point. More than 37,000 people were in emergency shelters, after 8,000 families had moved to 9,000 hotel rooms.

"This is an unprecedented event," said Alex Amparo, assistant administrator for recovery at the Federal Emergency Management Agency.

Joel Myers, AccuWeather's founder and chairman, called Harvey "the worst natural disaster in American history."

FEMA Administrator Brock Long, had a crisp answer Thursday for his prediction for Harvey for the next few days, as he worked on the aftermath in Houston.

"For Harvey to exit the nation, hopefully," Long said.

Contributing: The Tennessean.