Super Typhoon Haishen bombed into a mighty category 4 storm with 155 mph winds on Thursday, becoming Earth’s third-strongest storm of 2020. Haishen is expected to hit South Korea on Sunday, making the third landfalling typhoon in Korea (including both North Korea and South Korea) in a two-week period.
On August 27, Typhoon Bavi made landfall over North Pyongan Province, North Korea, as a minimal category 1 typhoon with 75 mph winds. On September 2, Typhoon Maysak made landfall as a category 2 storm with 100 mph winds just west of Busan, South Korea’s second-largest city and the world’s fifth-largest port.
Haishen put on an impressive display of rapid intensification on Thursday, strengthening in 24 hours from a low-end category 3 storm with 115 mph winds to a 155-mph super typhoon with a central pressure of 915 mb by 2 a.m. EDT Friday, according to the Joint Typhoon Warning Center (JTWC). Haishen maintained that intensity through the 11 a.m. EDT Friday advisory, when the typhoon was located over the record- to near-record warm waters about 700 miles south of Japan, heading northwest at 10 mph towards Korea. Haishen was already bringing heavy rains to the islands south of mainland Japan, as seen on Japanese radar.
Only two storms so far in 2020 have been stronger than Haishen: category 5 Tropical Cyclone Harold in the Southeast Pacific, which peaked with 165 mph winds and a pressure of 912 mb on April 6, and category 5 Tropical Cyclone Amphan, which peaked with 160 mph winds and a pressure of 907 mb on May 18 in the North Indian Ocean.
Forecast for Haishen
Haishen likely has hit its peak intensity, with the JTWC forecast calling for slow weakening to begin on Saturday morning. Haishen will be over record- to near-record warm ocean waters of 30 – 31 degrees Celsius (86 – 88°F) through Saturday. But it will cross over the cold wake left by Typhoon Maysak, to the south of Korea, by Sunday morning, perhaps inducing more rapid weakening. Haishen is expected to pass near the Japanese island of Amami Oshima, located about 100 miles northeast of Okinawa, around 2 a.m. EDT Sunday. Storm chaser James Reynolds is on Amami Oshima (population 73,000), and will be sending reports via Twitter (https://twitter.com/EarthUncutTV).
JTWC predicts that Haishen will hit South Korea on Sunday afternoon (U.S. EDT) as a weakening category 3 or category 2 storm. The typhoon likely will bring significant wind and storm surge damage to the coast. Even if Haishen passes far enough west of Busan to spare the city its strongest winds, the storm’s broad, powerful circulation likely will push a substantial storm surge toward the Busan area, where the geography is particularly prone to surge impacts.
What’s more, typhoons appear to be delivering larger storm surges to the Busan area even after taking into account sea-level rise caused by climate change. A 2016 study in the Journal of Coastal Research led by Sang Myeong Oh and co-authors found that typhoon landfalls from 1962 to 2014 drove a seven-inch increase in the annual maximum surge height in Busan, a rate of increase about 50% higher than the local trend in mean sea-level rise. The researchers attributed the higher surges to stronger typhoons resulting from increasing sea surface temperatures and decreasing wind shear.
It appears that Typhoon Maysak’s storm surge on September 2 in Busan was not severe, possibly because Maysak’s angle of approach was somewhat oblique (from the south-southwest) and because Maysak’s eastern eyewall and its strong onshore winds ended up reaching the coast east of the metropolitan area. In contrast, Haishen is expected to strike west of Busan, and the typhoon’s more perpendicular angle of approach would suggest more storm surge in Busan.
Another serious concern is the widespread four-to-eight inches of rain Haishen is expected to dump over both North Korea and South Korea. These rains will be falling atop ground soaked, due to South Korea’s second wettest monsoon season on record and the passage of Typhoon Bevi and Typhoon Maysak.
An unprecedented battering for Korea
According to NOAA’s historical hurricanes database, Korea between 1945 and 2019 has not been hit by three typhoons (sustained winds of at least 74 mph) in one year, so Typhoon Haishen’s landfall will be historic. The NOAA database lists 14 typhoons that have passed over South Korea prior to 2020 – 10 at category 1 strength, three category 2s and one category 3. Only three typhoons passed over North Korea prior to 2020, all minimal category 1 storms with 75 mph winds.
Typhoon Maysak is being blamed for two deaths in South Korea and three in Russia. In addition, 41 crew members of a livestock ship are missing after their ship sank in the typhoon. Two crew members have been rescued.
Damage reports from North Korea from Typhoon Bavi’s landfall there are hard to come by, but there are reports that the typhoon caused major flooding in portions of the secretive nation.
Four areas in the Atlantic to watch
In the Atlantic, the National Hurricane Center (NHC) was still issuing advisories for Tropical Depression Omar on Friday. Omar was located in the remote North Atlantic in the waters between Bermuda and Newfoundland, Canada, and it is not a threat to any land areas. Omar will likely dissipate by Saturday.
The 2 p.m. EDT Friday Tropical Weather Outlook from NHC was a busy one, highlighting three disturbances with the potential to develop into tropical cyclones. NHC designated a tropical wave near 11°N, 38°W as 91L. Satellite images showed 91L had changed little since Thursday, with an elongated surface circulation and a modest amount of heavy thunderstorm activity that was being hampered by dry air and high wind shear.
That shear and dry air are predicted to abate by Monday, giving 91L the potential to develop into a tropical depression. NHC gave 91L two-day and five-day odds of development of 20% and 30%, respectively. This system is predicted to meander in the central tropical Atlantic at speeds of around five mph over the coming five days, and has modest support for development from the top three models for predicting tropical cyclone genesis.
A large and complex tropical wave just west of the Cabo Verde Islands, designated 92L by NHC on Friday afternoon, was headed west to west-northwest at roughly 15 mph. Satellite images showed the wave had changed little since Thursday, with a modest amount of poorly organized heavy thunderstorm activity, but a good deal of spin. The system was at the edge of a large area of dry air associated with the Saharan Air Layer, and the dry air may interfere with development through the weekend. When the wave reaches the central Atlantic on Monday and Tuesday, passing to the north of 91L, it is expected to find a moister atmosphere with low-to-moderate wind shear, increasing chances of development. Models give this wave strong support for development. NHC gave the wave two-day and five-day odds of formation of 40% and 80%, respectively. An interaction with 91L may occur, making the future tracks of both of these disturbances difficult to predict.
A new tropical wave will emerge from the coast of Africa on Sunday, and it is predicted to head west to west-northwest at roughly 15 mph through the Cabo Verde Islands early next week. This wave has strong model support for developing into a tropical depression by Wednesday. NHC gave it two-day and five-day odds of formation of 0% and 60%, respectively.
The next name on the Atlantic list of storms is Paulette. The earliest sixteenth named storm on record for the Atlantic is Philippe from September 17, 2005. Including Paulette, only six more names remain on the 2020 Atlantic list before NHC will have to turn to the Greek alphabet, a last resort that’s been used only in 2005. That unforgettable year produced tropical storms Alpha, Beta, Gamma, Delta, Epsilon, and – on December 30 – Zeta.
With the Labor Day weekend at hand, there will be no new post here on the tropics until Sunday, September 6, at the earliest.
Bob Henson contributed to this post.
Posted on September 4, 2020 (3:08pm EDT).