(CNN) -- Tropical Storm Barbara strengthened Tuesday in Mexico's Pacific coast, where it's expected to make landfall, forecasters said.
The storm, with maximum sustained winds of 45 mph (75 kph), is stationary about 120 miles (195 kilometers) south-southwest of Salina Cruz. It's expected to move to the north and make landfall in Mexico on Wednesday, the U.S. National Hurricane Center said.
"Additional strengthening is forecast tonight and on Wednesday before the center of Barbara reaches the coast," forecasters said. "Weakening is forecast after landfall and Barbara should dissipate over southern Mexico by Thursday."
Up to 10 inches of rain is possible in southeastern Oaxaca state, the hurricane center said.
A tropical storm warning is in effect from Lagunas de Chacahua to Boca de Pijijiapan.
It means that tropical storm conditions are expected in the area within 12 to 24 hours.
CNN's Steve Almasy and Taylor Ward contributed to this report.