Who needs an ‘extremely dangerous’ Category 4 hurricane?

Written by Staff Writer

More than 60 of the 30 most active hurricane seasons since 1980 have occurred since 2000, and 2018, which set another record, was no exception. The Atlantic hurricane season, which runs from June 1 to November 30, has been highly active since the 1990s, and of the 20 most active Atlantic hurricane seasons, 18 occurred since 2000.

The forecast calls for seven named storms: one strong hurricane (hurricane strength or higher), and seven named tropical storms: three hurricane strength, and five named tropical storms. The first named storm of the Atlantic season will be named Cindy on May 29, according to the forecast.

The Saffir-Simpson Hurricane Wind Scale only allows for Category 1, Category 2 and Category 3 hurricane level winds, which at present means a storm could cause sustained winds of 74 mph or greater, which would be felt onshore, or an island.

In order to qualify as an “extremely dangerous” Category 4 storm, winds need to be 131 mph or higher, making it a Category 5. According to the National Hurricane Center, a storm reaching the 100 mph threshold (Category 4) would be responsible for 2,900 fatalities in the United States. Only two Category 4 storms have made landfall in the US since 1900. The first was in 1965, when Hurricane Camille made landfall in Mississippi, and the second was in 2017, when Hurricane Harvey made landfall in Texas.

Flier on Biscayne

The last time two Category 4 storms made landfall in the US was in 1992, when Hurricane Andrew made landfall in Florida and Hurricane Wilma made landfall in Florida. Unfortunately, Wilma and Hurricane Katrina, the only Category 5 hurricane to make landfall in the US in the 20th century, were both Category 4 storms in the Atlantic basin in 2005.

A one-in-80-year Hurricane Andrew, made landfall in southern Miami-Dade County, Fl., on September 25, 1992. A long-duration landfall is about the likelihood of seeing a Category 4 hurricane in any given season, according to the National Hurricane Center. The 20 most active hurricane seasons occurred between 1940 and 1970.

2016 hurricane season in 4 by CNN

While Hurricane Maria caused catastrophic damage in Puerto Rico in September 2017, the US territory had already endured its biggest hurricane loss, with the 1938 hurricane bearing down on the island, according to FEMA. Maria was the strongest hurricane to make landfall in Puerto Rico in 100 years. It had sustained winds of up to 185 mph, making it the strongest storm to make landfall in the Northern Hemisphere in 2018 and the fourth strongest ever. And it wasn’t the first of Puerto Rico’s other three hurricanes that season, either, as Hurricane Irma had sustained winds at 145 mph.

Maria and Irma also generated extensive flooding, with Maria contributing more than 14 million feet of rain. From 1941 through 1980, only the 1938 hurricane and “The Big One” in Galveston, Texas, had larger rainfall amounts on record in the Atlantic basin.

Pacific hurricane season

The Pacific hurricane season lasts from June 1 to November 30. Last year, this calendar year was the stormiest ever recorded in the region, with 10 of the 12 seasons since 1950 having been above average, according to the National Oceanic and Atmospheric Administration.

The Pacific hurricane season is influenced by what meteorologists call the monsoon circulation, which is the atmospheric circulation where humid sea and atmospheric conditions meet at a central point to form a multi-day rainfall event.

The rainfall event, according to NOAA, could also be influenced by the tropical central high pressure pattern, which is a frontal system or core of upper level winds. While both can bring rain to the tropical central Pacific, the structure of the high pressure may not impact the southwest Pacific, so rainfall from tropical storms and hurricanes there may depend on how strong they are and where they track, according to the Center.

The west-central Pacific rainfall event usually produces heavy rain, while the eastern Pacific rainfall event typically features cool and moist, or subtropical, features. Southeast Asia, Africa and Australia can also experience heavy rain as the monsoon circulation then interacts with the subtropical storm systems near Asia and Africa.

Copyright 2018 CNN

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