Super Typhoon Goni exploded into Earth’s most powerful storm of 2020 as a category 5 storm with 180 mph winds in the waters to the east of the Philippines, at 11 a.m. EDT Friday, October 30. Goni is expected to make landfall on Luzon Island in the Philippines on Sunday as a category 4 storm, and pass very close to the capital of Manila at category 1 strength or stronger.
Goni put on an extremely impressive bout of rapid intensification beginning at 0Z October 28, strengthening by 145 mph, from a 30-mph tropical depression to a 175-mph super typhoon, in 54 hours. According to Sam Lillo, only five storms in the global tropical cyclone database have achieved a 145-mph increase in 54 hours or less: Typhoon Vera in 1959 in the northwest Pacific; Hurricane Linda in 1997 in the northeast Pacific; Cyclone Zoe in 2002 in the southeast Pacific; Hurricane Wilma in 2005 in the Atlantic, and Hurricane Patricia in 2015 in the northeast Pacific.
Forecast for Goni
Goni took advantage of nearly ideal conditions for intensification on Thursday and Friday, with light wind shear less than 10 knots, a very moist atmosphere, ocean temperatures of 30 – 31 Celsius (86 – 88° F), and an ocean heat content of 150 kiljoules per square centimeter. These favorable conditions are expected to persist through Saturday. However, the typhoon will experience a less favorable upper-level outflow pattern, which should cause some weakening. In addition, satellite imagery suggested on Friday that the tiny eight-mile diameter eyewall of Goni was probably about to collapse and be replaced by a new eyewall with a much larger diameter. This process, known as an eyewall replacement cycle, typically results in a weakening of the storm’s winds by 10-20 mph.
The official Joint Typhoon Warning Center forecast at 11 a.m. EDT Friday called for Goni to be a weaker but still devastating 145-mph category 4 typhoon at landfall in Luzon early on Sunday, November 1 (U.S. EDT). Goni is a relatively small typhoon, and land interaction will weaken the storm rapidly as it passes over Luzon. However, Goni may pass close enough to the megacity of Manila (metro area population, 13 million) to bring the eyewall winds of the storm to the world’s most densely populated city. At that time, the 12Z Friday run of the HWRF model predicted that Goni would be a category 1 typhoon with 85 mph winds.
Winds of that magnitude in Manila are likely to cause a major disaster. The most recent typhoon to pass within 30 miles of Manila was Typhoon Rammasun of 2014 (known as “Glenda” in the Philippines), which passed 25 miles to the south of Manila as a category 2 storm with 105 mph winds. Rammasun was the third-costliest typhoon in Philippines history, with $885 million in damage. The typhoon killed 106 people in the Philippines and knocked out power to 90% of Manila.
Once Goni emerges into the South China sea after crossing Luzon, high wind shear, drier air, and cooler sea surface temperatures will likely prevent significant re-intensification. Goni is predicted to hit storm-weary Vietnam on November 4 as a tropical storm.
Goni is Earth’s third category 5 storm of 2020
Super Typhoon Goni joins Cyclone Amphan (160 mph winds in the North Indian Ocean in May) and Cyclone Harold (165 mph winds in the Southeast Pacific in April) as one of Earth’s three category 5 storms of 2020. Earth averaged 5.3 Category 5 storms per year between 1990 and 2019, according to ratings made by NOAA’s National Hurricane Center and the U.S. Navy’s Joint Typhoon Warning Center, so two more Cat 5s would make it a near-average year in that respect.
Post-season analysis finds an extra category 5 typhoon in 2019
In 2019, there were six category 5 tropical cyclones, and not five, as originally thought, according to the 2019 JTWC best track for the Western Pacific, released last month. There are three highly notable changes in the re-analysis (thanks go to Jasper Deng for this information):
1. Typhoon Bualoi, originally assessed as a category 4 typhoon with 145 mph winds, was upped to a 160-mph category 5 super typhoon.
2. Typhoon Hagibis’ winds were upgraded to a remarkable 185 mph. In 22 hours, Hagibis’ winds increased by 115 mph. This comes very close to the world record for fastest 24-hour intensification: 120 mph, set by Hurricane Patricia off the Pacific coast of Mexico in October 2015.
3. Super Typhoon Halong’s winds were upped from 180 mph to 190 mph. By one method of classifying tropical cyclones, Halong was Earth’s eighth-strongest storm ever.
Two other tropical cyclones just missed achieving category 5 status in 2019, topping out with 155 mph winds (157 mph winds are the threshold for a Cat 5): Cyclone Fani in the North Indian Ocean on May 2, and Cyclone Ambali in the Southwest Indian Ocean. Ambali is notable for setting a mark for the largest 24-hour intensification on record in the Southern Hemisphere, after it intensified 115 mph in just 24 hours. The previous record was 110 mph in 24 hours by Cyclone Ernie in 2017. No final re-analysis for these storms has yet been released.
Strongest tropical cyclones are getting stronger
Scientists theorize that a warming climate should make the strongest tropical cyclones stronger, since hurricanes are heat engines that extract heat energy from the oceans, converting it to kinetic energy in the form of wind. In a 2019 Review Paper by 11 hurricane scientists, “Tropical Cyclones and Climate Change Assessment: Part I. Detection and Attribution“, 10 of 11 authors concluded that the balance of evidence suggests a detectable increase in the average intensity of global hurricanes since the early 1980s; eight of those 11 concluded that the balance of evidence suggests that human-caused climate change contributed to that increased intensity.
All those 11 authors agreed that the balance of evidence suggests that the proportion of all hurricanes reaching category 4-5 strength has increased in recent years; and eight of them concluded that the balance of evidence suggests that human-caused climate change contributed to that increase.
A 2019 five-minute video by Peter Sinclair of Yale Climate Connections includes my analysis on how hurricanes are changing in the new warming climate.
We plan to do the next “Eye on the Storm” post on Sunday afternoon.
Posted on October 30, 2020 (4:43 pm EDT).