Infrared image of Maysak
Infrared image of Typhoon Maysak at 1400Z (10 a.m. EDT) Monday, August 31, 2020. The island of Okinawa is outlined just to the northeast of Maysak's eye. (Image credit: SSEC/CIMSS/University of Wisconsin)

After sweeping across Japan’s Ryukyu Islands on Monday night local time, powerful Typhoon Maysak is headed for a likely Wednesday landfall in South Korea that may lead to widespread and potentially severe damage.

At 8 a.m. EDT Monday, August 31 (3 p.m. Tuesday Korea Standard Time), Maysak was about 110 miles south-southwest of Kadena Air Force Base on the island of Okinawa, according to the U.S. Joint Typhoon Warning Center, JTWC, which reported that Maysak was packing 1-minute sustained winds of 125 mph, the equivalent of a Category 3 hurricane.

Maysak was on track to pass directly over or just west of tiny Kumejima island, where storm chaser James Reynolds (@EarthUncutTV) was stationed. Kumejima has only a few thousand residents. Maysak’s center is likely to pass about 40-50 miles west of more populous Okinawa, which has more than a million residents. At that distance, the island will not feel the full brunt of the storm. Intense squalls will be possible, though, as Maysak has a large circulation. Wind gusts of more than 60 mph were reported at Kadena AFB between around 10 and 11 a.m. EDT Monday.

Maysak could produce far more widespread damage later this week. Forecast models have consistently taken Maysak on an arcing path north and northeast into South Korea by Wednesday. Busan, the nation’s second largest city and the world’s fifth largest port, is expected to end up on the typhoon’s dangerous right-hand side, with destructive winds and storm surge a real threat. Maysak then will angle leftward, taking an unusual course near the peninsula’s east coast that could bring torrential rains and high wind across both South and North Korea and into far northeast China as the typhoon transitions into an unusually strong extratropical storm.

Maysak’s rapid motion will help limit total rainfall amounts, but the Korean peninsula is primed for flooding. Only a week ago, Typhoon Bavi – a weaker storm than Maysak – dumped heavy rain as it passed west of the peninsula before making landfall in western North Korea. What’s more, South Korea has endured one of its wettest and longest monsoon seasons on record this year, lasting for 54 days, according to the Korea Meteorological Administration. As noted by the Korea Herald, the nation as a whole averaged roughly 920 millimeters (36.22 inches) of rain from June 1 through August 15, compared to the long-term average of around 570 mm (22.44 inches).

Figure 1
Figure 1. Only one typhoon is known to have made landfall on the Korean peninsula at major hurricane (Category 3) strength: Sarah (1959). Maemi (2003) and Faye (1995) weakened to Category 2 strength just before landfall. (Image credit: NOAA Historical Hurricane Tracks)

Maysak appears destined to be among South Korea’s most intense typhoons on record, and perhaps the most intense. Typhoons reaching the south coast are among the most dangerous for the nation, because they are less likely to encounter the cooler waters and higher wind shear that often prevail further north. Multiple runs of the HWRF, among the top models for tropical cyclone intensity, have projected a central pressure for Maysak near the South Korea coast between 935 and 945 mb. The lowest pressure recorded in any typhoon in South Korea is 950 mb, observed during Typhoon Maemi on Jeju Island on September 12, 2003.

Meimi, which had peaked as a Category 5-equivalent super typhoon, made landfall just west of Busan. Severe impacts from Meimi included 117 deaths, $4.8 billion in damage (USD 2003), some 5,000 homes destroyed, and widespread crop damages. The only other comparable typhoon to strike the South Korea mainland, Sarah (1959), also made landfall just west of Busan. Sarah’s impacts were catastrophic, including at least 669 deaths and 14,000 destroyed homes.

A plethora of percolating Atlantic systems brings close to brief lull

The brief calm spell in the Atlantic after Hurricane Laura’s destructive landfall in Louisiana has drawn to an abrupt end. In its tropical weather outlook at 8 a.m. EDT Monday, August 31, the National Hurricane Center was tracking no fewer than four systems that could become tropical cyclones.

Figure 2
Figure 2. GeoColor satellite image of Invest 99L at 1550Z (11:50 a.m. EDT) Monday, August 31. (Image credit: RAMMB/CIRA/Colorado State University)

The most concerning threat to land this week is Invest 99L, a disturbance in the eastern Caribbean Sea. As of Monday morning, 99L was looking more organized, with mid-level spin evident, but not yet any low-level circulation. 99L is embedded in a moderately moist atmosphere (mid-level relative humidity around 60-65%), and it will be passing over warm sea-surface temperatures of around 29°C (84°F).

Wind shear of 15-20 knots is expected to keep the brakes on 99L as it crosses the Caribbean, so any development should be gradual, at least into midweek. Models agree that strong east-to-west steering currents will drive 99L toward the coast of Belize and northern Honduras by late this week, most likely as a strong tropical storm. Prolonged heavy rains are possible, especially in northern Honduras. NHC gave 99L 70% odds of becoming at least a tropical depression by Wednesday and an 80% chance through Saturday.

Figure 3
Figure 3. GeoColor satellite image of Invest 90L at 1550Z (11:50 a.m. EDT) Monday, August 31, 2020. (Image credit: RAMMB/CIRA/Colorado State University)

The other system of immediate interest, Invest 90L, is brewing just off the southeast U.S. coast, but it’s not expected to move inland. Surface pressures are high, and dry air was keeping shower and thunderstorm activity (convection) modest around this weak low on Monday morning.

However, a low-level circulation appeared to be taking shape. Light wind shear (below 10 knots), a moist atmosphere (relative humidity around 70%), and warm SSTs around 29-30°C (84-86°F) may allow 90L a chance for modest development before wind shear increases dramatically by midweek. Upper-level southwesterlies will push 90L northeastward, parallel to the Southeast coast, before it heads out into the Atlantic. NHC gave 90L a 70% chance of becoming at least a tropical depression by Wednesday or by Saturday.

Torrential rains in China cause $2.9 billion in damage, leave 63 dead or missing

The next two names on the Atlantic list are Nana and Omar. The earliest fourteenth named storm of any Atlantic season in records back to 1851 is Nate (September 5, 2005), so this year is likely to continue setting a record pace.

Figure 4
Figure 4. Infrared satellite image from the eastern tropical Atlantic at 1545Z (11:45 a.m. EDT) Monday, August 31, showing two disturbances of interest. (Image credit:

There is plenty of time to watch two other tropical waves in the far eastern Atlantic. One just moving off the African coast (right side of image) appeared healthier on Monday, with a broad field of convection. NHC is giving it a 30% chance of development between Wednesday and Saturday. A smaller, slower-moving wave just downstream (left side of image) was struggling to maintain its convection and is not expected to develop, with only a 10% chance later this week.

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Posted August 31, 2020 (1:43 p.m. EDT).

Bob Henson is a meteorologist and journalist based in Boulder, Colorado. He has written on weather and climate for the National Center for Atmospheric Research, Weather Underground, and many freelance...

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