New Tropical Storm Roslyn to strengthen and threaten western Mexico

AccuWeather forecasters say the Eastern Pacific basin has come to life following a brief break in tropical activity. A brewing tropical system south of Mexico became Tropical Depression 19-E on Wednesday evening was upgreated to Tropical Storm Roslyn on Thursday. Rosyln is set to bring heavy rain and damaging winds to western portions of Mexico in the next few days as a hurricane.

Tropical Storm Julia was the last storm to roam in the East Pacific after it crossed over from the Atlantic basin more than a week ago. The last storm to actually form in the basin was Tropical Storm Paine. Paine developed in the open waters of the Pacific during the first week of October and was never a threat to land.

Unlike Paine, forecasters say the new tropical system in the basin could produce significant impacts.

Roslyn is located in an environment where atmospheric factors are conducive for further development.

"It is located in a zone of low, vertical wind shear and warm waters, which should aid in further strengthening to hurricane by late week," AccuWeather Senior Meteorologist Adam Douty explained.


Forecasters say it will likely take a path that parallels Mexico's southern coastline for a few days before it turns toward the northeast. This path is forecast to place the system on a crash course with the states of Sinaloa, Nayarit and Jalisco later this weekend into early next week.

AccuWeather forecasters are concerned it could reach Category 2 hurricane strength (maximum-sustained winds of 96-110 mph or 154-177 km/h) on the Saffir-Simpson Hurricane Wind Scale before landfall, depending on how quickly this brewing system is able to organize and strengthen.

"Regardless of the intensity of the system at landfall, flooding rain and mudslides are going to be a threat," Douty cautioned.

The heaviest rain from Roslyn is forecast to arrive for portions of the Mexican coastline during the weekend as it begins its turn toward land. Drenching rainfall from this system will quickly raise flooding concerns, especially for areas that endured a direct hit from Hurricane Orlene in the first days of October.

Torrential rainfall can rapidly produce areas of flash flooding as well as force area streams and rivers to swell. Heavy rainfall can also work to compromise the integrity of area soil and lead to dangerous mudslides, AccuWeather meteorologists say.

In addition, damaging winds are possible near where Roslyn ultimately makes landfall. Damage to trees, power lines and some structures is not out of the question depending on how strong the system is at landfall.

Even ahead of direct impacts to land, rough seas and dangerous rip currents will be a significant concern for the rest of the week.

By early next week, the circulation of Roslyn is expected to be ripped apart by Mexico's mountainous terrain. Forecasters say its possible some of the then tropical rainstorm's lingering moisture gets pulled into the south-central United States.

"A storm moving out of the Rockies will pick up some of the tropical moisture later this weekend into the following week," AccuWeather Senior Meteorologist Bill Deger explained. This could result in some much-needed rain, which will include the risk of gusty thunderstorms, from Texas into the central Plains, he added.

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