Polo, a tropical storm in the Pacific Ocean, is expected to become a major hurricane this week

MIAMI (AP) — Tropical Storm Polo will rapidly intensify in the Pacific Ocean and become a major hurricane later this week, forecasters said Monday.

Polo could bring heavy rain, rough surf and tropical-storm-force winds to parts of Mexico late Tuesday into early Wednesday, according to an advisory from the Miami-based National Hurricane Center.

Meteorologists predicted Monday that Polo would drop 4 to 8 inches of rain, with isolated totals near 12 inches, across coastal portions of the Mexican states of Guerrero and Michoacán through Thursday. Flooding and mudslides were possible.

Still a tropical storm as of Monday, Polo had maximum sustained winds of 65 mph. It was centered about 255 miles south-southeast of Manzanillo, Mexico, and 200 miles southwest of Zihuatanejo. The system was moving east at 5 mph.

Farther west in the Pacific Ocean, Tropical Storm Odalys was far from land but expected to become a hurricane by midweek.

Odalys had maximum sustained winds of 45 mph on Monday. It was located just over 1,400 miles west-southwest of the southern tip of Mexico's Baja California peninsula. It was moving northwest at 12 mph.

In the Atlantic Ocean, Tropical Storm Fay was weakening. Top winds were down to 50 mph, and Fay was 430 miles southwest of the Azores.

No Atlantic hurricanes have formed yet this year, and this year has set a record for the longest a season has gone without a hurricane. The effects of this year's El Niño crush storms before they get going.