(CNN) -- Hurricane Barbara weakened to a tropical storm Wednesday after it crashed ashore along Mexico's southern Pacific coast.
Barely a hurricane, the moisture-laden storm made landfall in the state of Chiapas, about 20 miles west of Tonala, the U.S.-based National Hurricane Center said.
Barbara had sustained winds then of 75 mph, and was moving north-northeast at 9 mph. Winds weakened to 50 mph by Wednesday night.
The storm was about 50 miles west-northwest of Tuxtla Gutierrez, according to the hurricane center's last advisory.
Barbara is expected to dump between 6-10 inches of rain, with up to 20 inches possible in some areas.
"These rains could cause life-threatening flash floods and mud slides," the hurricane center warned.
On the forecast track, Barbara is expected to move over southeastern Mexico into Thursday.
Rapid weakening is forecast during that time. Barbara is expected to dissipate within days.
The storm is the second of the eastern Pacific hurricane season, after Tropical Storm Alvin this month.