Tropical Storm Bonnie Could Achieve A Rare Feat: Changing Oceans

Tropical Storm Bonnie (finally) formed in the far southern Caribbean Sea on Friday afternoon, becoming the second storm of the 2022 Atlantic hurricane season. We’ve been watching this system for a while now, performing its will-it-or-won’t-it routine as it skimmed the northern shores of South America.

This tropical storm will be a big deal for folks in Central America. Very heavy rainfall over mountainous terrain will lead to widespread and life-threatening flash flooding across much of Nicaragua and Costa Rica through the weekend.

The National Hurricane Center‘s 11:00 a.m. EDT update on Friday showed Tropical Storm Bonnie as a minimal tropical storm, moving west a decent clip toward the Nicaraguan coast. Forecasters expect the storm to make landfall on Friday night, lingering through the day on Saturday for many areas.

Even weak tropical systems are bad news when they hit Central America. The region’s rugged terrain exacerbates flash flooding from tropical systems that cross the area. The NHC’s advisory calls for 4-8 inches of rain, with localized amounts of a foot or more possible.

Bonnie is a strange tropical storm that has the potential to land a spot in the recordbooks. Not only is this one of the farthest-south storms ever recorded—thanks to a strong ridge of high pressure over the Atlantic shunting it far to the south—but forecasters expect it to survive its encounter with Central America and emerge over the eastern Pacific unscathed.

It’s very, very rare for tropical systems to cross from the Atlantic to the Pacific intact. Land interaction typically shreds these storms apart, leaving only their cloudy remnants to wander into the adjacent ocean and look for more opportunities to organize into a new storm.

But the latest NHC forecast calls for Tropical Storm Bonnie to cross Nicaragua intact this weekend,  thanks in large part to its swift forward speed and the narrowness of this part of Central America. Forecasters expect Bonnie to emerge in the eastern Pacific on Saturday as a tropical system with the same center of circulation it developed over on the Atlantic side. 

If the storm accomplishes this rare feat, it’ll retain its Atlantic name. Forecasters expect Bonnie to continue its Pacific adventure even stronger than it started life, potentially strengthening into a hurricane as it parallels Mexico’s western coast heading into early next week.

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