GUATEMALA CITY (AP) — The remnants of Tropical Storm Matthew drenched parts of Central America and southern Mexico on Sunday, a day after it weakened to a tropical depression.

The storm's forward movement slowed to a crawl and top wind speeds fell to about 25 mph (35 kph). Its center was about 40 miles (65 kilometers) southeast of the Gulf coast city of Villahermosa — an area already hit by severe flooding in recent months.

Forecasters at the U.S. National Hurricane Center in Miami said the system's slow movement means it could produce rainfall totals of 6 to 10 inches (15 to 25 centimeters) over parts of Mexico and Guatemala, threatening deadly flash floods and mudslides.

Mexico's National Water Commission said it was working to widen and deepen channels below dams in preparation.

In Honduras, the National Emergencies Commission said at least 6,600 people in eight coastal provinces were forced from their homes by Matthew, and nine bridges damaged by flooding.

The storm also displaced more than 500 people and blocked highways in neighboring Guatemala.

Guatemala has already been buffeted by heavy rains in recent months that killed about 274 people and caused $1.1 billion in damage, according to government estimates.

Matthew made landfall as a tropical storm Friday on Nicaragua's Caribbean coast and quickly crossed into Honduras, where it toppled utility poles and left thousands without power for hours.

Meanwhile, far from land in the open Atlantic, Lisa weakened to a tropical depression early Sunday with maximum sustained winds of 35 mph (55 kph). Further weakening is expected.