A new tropical storm has formed in the Pacific Ocean, potentially bringing dangerous winds, rain and floods as it rolls up the West Coast.

The 13th named storm of this Pacific hurricane season has been designated as Mario and was described by the National Hurricane Center (NHC) on Friday as a ‘mini’ tropical storm.

Mario formed about 23 miles off the coast of Guerrero, Mexico, with sustained winds near 40 mph after rapidly strengthening overnight. 

The storm is moving west-northwest at about 14 mph, roughly parallel to the southwestern Mexican coastline.

It is expected to continue on this track for several days under the influence of a high-pressure ridge over northern Mexico and the Pacific Ocean. 

A tropical storm watch was in effect for parts of the Michoacan state. It spanned from Lazaro Cardenas to Punta San Telmo. 

Forecasters have issued warnings that Mario is anticipated to intensify while it travels northward toward the southwestern United States. Experts from AccuWeather indicate that the storm might develop into a hurricane before it approaches the Baja California Peninsula.

Heather Zehr, a senior meteorologist at AccuWeather, stated: ‘Some moisture might start appearing as clouds and occasional showers as soon as Tuesday in certain areas of Southern California, Arizona, and southern Nevada, but it is more likely to happen from Wednesday onward.’

This is a developing story. More updates to follow. 

Tropical storm Mario formed Friday morning off the coast of southern Mexico

Mario is expected to keep moving west-northwest for at least the next four days under the influence of a mid-level ridge over northern Mexico and the eastern Pacific Ocean.

‘Mario will lead to rainfall totals of 2 to 4 inches, with local amounts of 6 inches, across southern Mexico through Sunday,’ the NHC alert reads.

‘This brings a risk of flash flooding, especially in areas of higher terrain.’

While Mario is currently off the coast of Mexico, meteorologists are keeping an eye out for any sudden shifts toward the US. 

ABC meteorologist Jorge Torres shared on X: ‘Still too early to know if it could impact Arizona or the Desert Southwest… but we’re keeping a close eye.’

The NHC noted that Mario is an abnormally small storm, which is making it difficult to predict its track or future intensity.

‘Model guidance is having a challenging time simulating Mario’s future due to the storm’s small size and proximity to Mexico’s coastal topography,’ the hurricane center shared.

If Mario stays offshore, some forecast models suggest it will soon reach warmer waters that could help it strengthen, though wind shear may slow its development. 

Mario is moving up around the west coast of Mexico and while it is

Even without making landfall, parts of the southern coast could still see heavy rain and dangerous surf over the next few days.

Mario comes as a departing storm is set to leave much of the US West drier and warmer this weekend, AccuWeather reported. 

The large storm that recently brought cooler air, heavy showers and gusty thunderstorms from the Rockies to near the Pacific coast will move out this weekend. 

However, the dry weather may be short-lived, as Tropical Storm Mario near Mexico could bring moisture northward next week.

From Wednesday morning through Thursday morning, many areas from the Rockies to the Interstate 5 corridor in the US received small amounts of rain, ranging from a few hundredths to several tenths of an inch. 

Some spots in Northern California and eastern Oregon picked up between 0.5 and 1 inch. Most of western Arizona, southern Nevada, and Southern California stayed dry.