Tropical Storm Julio formed off Mexico's Pacific coast on Saturday and was headed toward Baja California Peninsula.

The storm was forecast to brush the west coast of the peninsula near Cabo San Lazaro on Monday morning, and make landfall Tuesday further north near Punto Abreojos.

Forecasters said Julio was not expected to become a hurricane, though it will likely strengthen. The storm packed maximum sustained winds of 40 mph and was centered Saturday afternoon about 240 miles south-southeast of the tip of the Baja Peninsula, according to the National Hurricane Center in Miami.

"We think it's going to remain a tropical storm. There's not a zero chance of a hurricane but it's very small," said Richard Knabb, a senior hurricane specialist with the center.

A tropical storm watch was issued from Santa Fe on the west coast of the peninsula to Buenavista on the Gulf of California.

A watch means that tropical storm conditions are possible within 36 hours.

Julio was moving northwest at 12 mph.