MEXICO CITY, Sept. 25 (Xinhua) -- Tropical storm Rosa has formed off Mexico's Pacific coast, said Mexico's National Meteorological Service (SMN) on Tuesday.

According to SMN, Rosa was located about 620 kilometers southwest of the port city Manzanillo, in the Mexican western state of Colima, with wind speeds of approximately 75 kph with gusts up to 95 kph.

Experts predicted that the storm would grow to a Category 1 hurricane on Wednesday evening, and move northwest, parallel to the Mexican coast.

There is a possibility that Rosa will strengthen to a Category 2 hurricane on Friday, and last for two days.

For now, Rosa threatens the states of Nayarit, Jalisco, Colima and Michoacan, all in western Mexico, with heavy storms.

SMN is warning residents of these states to use extreme caution due to heavy rains, strong winds and high waves.

The northwest and west of Mexico has been enduring intense rains for the last week.

At least five people have died in the state of Sinaloa, and another seven were killed in the state of Michoacan due to flooding caused by heavy rains, local authorities reported.