Tropical Storm Octave pummelling Mexico's Baja California peninsula fizzled overnight into a tropical depression, US weather forecasters said Tuesday.

Octave however is still forecast to dump heavy rain in the region, the US National Hurricane Center said in its 0600 GMT bulletin.

All tropical storm warnings for Octave had been canceled, as the storm's maximum sustained winds dropped to near 35 miles (55 kilometers) per hour.

On the forecast track "the center of Octave or its remnants will be moving over the southern Baja California peninsula and the Sea of Cortez on Tuesday," the NHC said.

Mexico however is still preparing for potentially deadly flooding and landslides, as Octave is expected to drop between one and six inches of rain across Baja California and the mainland state of Sonora, "with isolated maximum amounts of eight inches possible."

The storm however may already have claimed victims: a single-engine Cessna 208-B plane with 14 people aboard went missing Monday after it took off from Loreto, a popular resort destination for Americans and Canadians in Baja California Sur state, officials said.

When the plane did not reach its destination a search was launched, but due to bad weather conditions related to Octave "we have unable to locate the airplane," read a statement from the secretariat of Communications and Transportation.

There was no immediate word on passengers on the plane which belongs to a charter company that flies between Baja California Sur and Sinaloa and Sonora states.

Octave arrives just three weeks after Mexico weathered the dual blast of storms Manuel and Ingrid.

At least 157 people were killed in the historic downpours, including 101 in the southern Guerrero state. Dozens were left missing in the mountainous village of La Pintada after a landslide buried a third of the community.

September's torrential rains left 1.7 million people homeless.

Meanwhile, Tropical Storm Priscilla, located some 600 miles (970 kilometers) southwest of the southern tip of Baja, weakened a bit, packing winds of up to 40 mph (65 kph), the NHC said.

Priscilla, which was heading north and forecast to soon turn northwest and away from land, was expected to also further weaken into a tropical depression on Tuesday, the Miami-based center said.