Category 5 Hurricane Otis Rapid Intensification Was 'Nightmare Scenario,' Historic Strike On Acapulco

Category 5 Hurricane Otis was a nightmare scenario of rapid intensification prior to landfall near a heavily populated city that had never experienced such a ferocious storm in modern times.

Here's what happened: Otis exploded from a tropical storm Tuesday morning to a Category 5 hurricane Tuesday night.

Rapid strengthening​ near landfall. This incredible rapid intensification happened less than 24 hours before Otis plowed ashore near Acapulco, Mexico just after midnight Wednesday with maximum winds of 165 mph.

This historic intensification was not forecast well. Otis was among the most prolific rapid intensification events on record not just in the Eastern Pacific, but globally. While a hurricane watch was issued Monday afternoon, and hurricane warning issued early Tuesday morning, computer model and National Hurricane Center forecasts severely underestimated its intensity.

Hurricane intensity forecasts have improved over the years. But, this stronger, faster intensification can happen with smaller storms, moving over deep, warm water with favorable winds aloft spreading apart and humid air. All those factors were in play with Otis.

It left those near the coast scrambling to prepare. Instead of expecting a strong tropical storm or Category 1 hurricane, per forecasts Tuesday morning, this part of the Mexican coast had to quickly prepare for a Category 4 or 5 hurricane in a matter of hours as Tuesday afternoon and evening's forecasts were abruptly shifted higher.

I​t happened near a major city not used to intense hurricanes. If all that wasn't dire enough, Acapulco hadn't seen a hurricane stronger than Category 1 pass near the city in its historical record dating to the mid-20th century.

B​ut this wasn't a Category 2 or even 3. It was the most intense landfall on record for Mexico's Pacific Coast.

T​his underforecast rapid intensification to a violent hurricane in the hours immediately before landfall over a city of 1 million people not used to strong hurricanes is a "nightmare scenario" hurricane forecasters and emergency managers dread.

I​t's likely no longtime residents, not to mention any tourists in town, had experienced a hurricane of the ferocity of Otis.

O​ther examples of intensification near landfall: There have been several recent examples of this unsettling rapid intensification.

L​ast September, Hurricane Ian rapidly intensified three different times, including briefly to Category 5 status before mauling southwest Florida as a Category 4 hurricane.

H​urricanes Ida, Laura, Michael and Harvey also rapidly intensified before their Gulf landfalls.

A​nd while not nearly as strong, tiny Humberto unexpectedly strengthened from a tropical depression to Category 1 hurricane in just 19 hours before moving ashore along the upper Texas coast in September 2007.

(​MORE: Why Small Tropical Cyclones Can Be Difficult To Forecast)

E​xpect more of this: Defined as at least a 35 mph increase in winds in 24 hours or less, rapid intensification is twice as likely to happen now in the Atlantic Basin compared to 30 years ago, according to a recent study.

A separate 2019 study found the chance of rapid intensification had increased from 1 in 100 in the early 1980s to a 1 in 20 chance by the 2010s.

S​ince a hurricane's potential intensity depends on a supply of deep, warm water, and moist air, it means hurricanes have a better chance of being stronger and intensifying rapidly ​in a warming world.

That's disconcerting, given the pockets of shallow, warm water that can exist near coastlines in the hurricane zone, as happened with Otis.

A​nd that remains a significant challenge for scientists developing more sophisticated computer models to accurately forecast the next such event with as much warning as possible.

Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. His lifelong love of meteorology began with a close encounter from a tornado as a child in Wisconsin. He studied physics at the University of Wisconsin-Madison, then completed his Master's degree working with dual-polarization radar and lightning data at Colorado State University. Extreme and bizarre weather are his favorite topics. Reach out to him on X/Twitter, Facebook and Threads. 

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