NASA image
Visible image from NASA's Terra satellite of Typhoon Maysak on August 31, 2020, after the storm had moved past Japan's Ryukyu Islands (outlined). (Image credit: NASA Worldview)

Fearsome Typhoon Maysak began angling toward the southern coast of South Korea on Tuesday, September 1, after swinging through Japan’s Kyushu Islands as the equivalent of a Category 4 hurricane. Maysak is on track to slam populous southeastern South Korea on Wednesday night local time with sustained winds that could exceed 100 mph, together with a destructive storm surge.

Typhoon Maysak could become one of South Korea’s strongest typhoons on record

Maysak’s eastern eyewall – the most dangerous part of this storm – passed directly over Japan’s tiny Kume Island on Monday night. A peak wind gust of 54 meters per second (about 122 mph) was reported at Kitihara on Kume Island, which received almost nine inches of rain in 24 hours, according to weather.com’s Jonathan Erdman. Hurricane chaser James Reynolds (@EarthUncutTV) documented shrieking winds and huge waves.

“Happy to report I saw no major building damage on Kumejima which is to be expected, these islands are built for the strongest typhoons,” Reynolds tweeted. “Power is out in many places and lots of cleaning up to be done.”

Maysak is continuing to track toward a potential landfall west of Busan – South Korea’s second-largest city and the world’s fifth-largest port. That track would put the Busan area on the storm’s more dangerous eastern side. 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 Korea and North Korea and into far northeast China as the typhoon transitions into a strong extratropical storm.

Even if Maysak 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 stronger surges to the Busan area even after sea-level rise due to climate change is taken into account. A 2016 study in the Journal of Coastal Research led by Sang Myeong Oh found that typhoon landfalls from 1962 to 2014 drove a seven-inch increase in the annual maximum surge height (AMSH) in Busan, a rate of increase about 50% higher than the local trend in mean sea level (MSL).

On the plus side, Maysak has embarked on a weakening trend that will cut its top winds prior to landfall. Vertical wind shear is increasing, and the typhoon’s once-distinct eye became fragmented on satellite imagery on Wednesday. Moreover, the western half of Maysak will be passing over a cool wake left behind by Typhoon Bevi, which passed west of the Korea Peninsula just a week ago. Sea surface temperatures (SSTs) in this wake are lower than the standard 26°C (79°F) threshold for sustaining a tropical cyclone (though much warmer just to the east, where the bulk of Maysak will be traveling). There is also the possibility of an eyewall replacement cycle, the “shedding” of an old eyewall that can reduce a tropical cyclone’s strength for a day or so. In this case, Maysak would have to rebuild a new eyewall quickly under less-than-optimal conditions before making landfall.

Figure 1. Forecast from the 6Z Tuesday, September 1 run of the HWRF forecast model showing Typhoon Maysak nearing landfall on the south central coast of South Korea at 15Z Wednesday (midnight Wednesday night Korea time) with a projected central pressure of 934 mb and top sustained winds of 90 knots (about 105 mph). This is not an official forecast of landfall location and strength. (Image credit: tropicaltidbits.com)

All things considered, it remains possible that Maysak will strike South Korea with a central pressure below the national record of 950 mb, as consistently indicated by multiple runs of the HWRF model (one of the best for tropical cyclone intensity).

Widespread 4-8 inch rains from Maysak will be falling atop ground soaked by South Korea’s second wettest monsoon season on record, and also by rains from Typhoon Bevi just last week.

Next up: Haishen

More trouble lies on the horizon with Tropical Storm Haishen, now gathering strength in the Northwest Pacific. Long-range models show that Haishen could reach Category 4 strength on a course that will take it over or near southwest Japan by Sunday, and perhaps toward the Korean peninsula as a weakening system after that.

Figure 2. Departures from average sea surface temperature (degrees Celsius) across the Northwest Pacific on September 1. (Image credit: tropicaltidbits.com)

Monsoon and typhoon season over the tropical Northwest Pacific had been remarkably calm until the last few days of August. For the first time in the satellite era, no typhoons were reported during July. As one might expect in the warming climate, the lack of activity to churn up the waters allowed the Northwest Pacific to warm to record or near-record levels (see image below). These warm waters will give a major boost to Haishen as it heads toward Japan.

Tropical Storm Nana expected to drench northern Honduras

On Tuesday morning, September 1, NOAA’s National Hurricane Center (NHC) dubbed a strong disturbance south of Jamaica Potential Tropical Cyclone 16. NHC uses the “potential tropical cyclone” (PTC) designation, first used in 2017, for any system that is not yet a tropical cyclone (meaning a center of low pressure with a warm core and a closed circulation at the surface) but one that could affect land as a tropical storm within 48 hours. The system was upgraded to Tropical Storm Nana on Tuesday afternoon.

Figure 3. GeoColor visible satellite image of Potential Tropical Cyclone 16 at 1600Z (noon EDT) September 1, 2020. (Image credit: RAMMB/CIRA/Colorado State University)

Though PTC 16 did not have a closed surface circulation on Tuesday morning, it was a healthy disturbance, with a distinct cluster of showers and thunderstorms (convection) and upper-level spin evident. The system was hustling westward at 18 mph with top sustained winds of 40 mph, moving atop warm SSTs of around 29°C (84°F).  On its upgrade to Nana, the winds were boosted to 50 MPH.

Oceanic heat content is very high along Nana’s path, so if the system does organize, it will have plenty of warm water to access. The atmosphere will be steadily moistening, with mid-level relative humidity climbing above 60%. Moderate to strong wind shear (10-20 knots) will be the main cap on any rapid strengthening of Nana.

NHC predicted Nana will head westward toward a likely landfall in Belize on Thursday. A tropical storm watch was issued for Belize and the north coast of Honduras. Given the mostly favorable conditions ahead of it, Nana could reach hurricane strength before landfall.

As Nana parallels the Honduras coast, its strongest winds are expected to remain offshore on the right-hand (north) side. Heavy rains may extend across the rugged coastal area and adjacent islands.

The next two names on the Atlantic list are Nana and Omar. The earliest fourteenth 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. GeoColor visible satellite image of Tropical Depression 15 at 1620Z (12:20 p.m. EDT) September 1, 2020. (Image credit: RAMMB/CIRA/Colorado State University)

Tropical Depression 15 clinging to life off the Southeast Coast

Tropical Depression 15 continued to spin on Wednesday morning about 140 miles east-southeast of Cape Hatteras, North Carolina. TD 15 was moving away from the southeastern coast at about 14 mph, and no U.S. impacts are expected. Westerly wind shear was keeping the disorganized convection associated with TD 15 well east of the center of circulation. As it moves across very warm waters (SSTs of 30°C or 86°F), the depression could briefly bump up to minimal tropical storm strength before it gives in to the destructive effects of rapidly increasing wind shear.

Far out in the eastern Atlantic, several tropical waves have tried to organize themselves without success over the past few days. NHC is now pegging a wave just coming off Africa with a 40% chance of development between Thursday and Sunday as it heads west across warm tropical waters. If it holds together, this system would not reach the longitude of the Lesser Antilles until next week.

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Posted September 1, 2020 (2:24pm EDT)

Bob Henson

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...

141 replies on “Typhoon Maysak on track to slam South Korea”

  1. Japan Meteorological Agency
    Tropical Cyclone Advisory #49 – 3:00 AM JST September 3 2020
    TYPHOON MAYSAK (T2009)
    =================================================
    Over land Korean Peninsula

    At 18:00 PM UTC, Typhoon Maysak (955 hPa) located at 35.5N 128.8E has 10 minute sustained winds of 80 knots with gusts of 115 knots. The cyclone is reported as moving north northeast at 18 knots.

    Storm Force Winds
    ===================
    120 nm from the center

    Gale Force Winds
    ===================
    270 nm from the center

    Dvorak Intensity:

    Forecast and Intensity
    =======================
    24 HRS: 46.8N 125.5E – Extratropical Low Over land northeastern China

    ——————————————————–

    Tropical Cyclone Advisory #21 – 3:00 AM JST September 3 2020
    TYPHOON HAISHEN (T2010)
    =================================================
    Sea East of the Philippines

    At 18:00 PM UTC, Typhoon Haishen (975 hPa) located at 20.0N 139.4E has 10 minute sustained winds of 65 knots with gusts of 95 knots. The cyclone is reported as moving west northwest at 10 knots.

    Storm Force Winds
    =================
    60 nm from the center

    Gale Force Winds
    =================
    210 nm from the center

    Dvorak Intensity: T4.0

    Forecast and Intensity
    =======================
    24 HRS: 21.4N 135.9E – 85 knots (CAT 4/Very Strong Typhoon) Okinotorishima waters (Ogasawara subprefecture)
    48 HRS: 23.1N 132.9E – 105 knots (CAT 5/Intense Typhoon) Sea South of Japan
    72 HRS: 25.8N 130.9E – 110 knots (CAT 5/Intense Typhoon) Sea South of Japan

    1. well, it’s there in the latest advisory. A 110 knots from RSMC which is a T7.0 on the Dvorak intensity.

      I wonder if JTWC will increase their advisory to 135-140 knots.

  2. Reed, get that passport in hand, reserve the plane ticket, and your bags and that sensor kit packed, start a “go fund my chase of Nana landfall”, we can all kick in for a burro to traverse Barranco road brother. We want touchdown live feeds! (Note: Bring goggles, swim fins and a snorkle). You can vacation in Punta Gordo after, if there are any funds left.

  3. That 1 road out of the rather small village of Barranco, Belize should be busy right now, it could get rather muddy later. Unless they traverse the jungle, it looks like the only escape route to any higher land. 996 at landfall on a village by the bay with a poor way out, even in mild 60mph breezes, does not seem like fun if there is any surge at all. Not like they have anywhere to run to.

    https://www.tropicaltidbits.com/analysis/models/?model=hmon&region=16L&pkg=z500a&runtime=2020090212&fh=228

  4. They are not “Garbage” when they are a threat to mariners and coastal residents. When you utilize modern technology you have to name any system that meets the criteria for storm classification. Every season has a certain amount of “Garbage” even blockbuster seasons such as 1933, more recently 2005. Every season is unique just like weather weenies, wishcasters, disaster mongers, Trolls and so forth. Many have their eyes open but just don’t see. On this date, in 1935, the Keys hurricane occurred. One of the worst ever. Other than that storm, most of the others were “Garbage” that year.

  5. The GFS 12z is not even being funny showing that storm approaching LA coast at 384 hrs. No reruns please. 2020 or no 2020…Korea is getting it bad enough with a high pair currently.

  6. …AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT REPORTS NANA HAS CHANGED LITTLE IN STRENGTH… 2:00 PM EDT Wed Sep 2
    Location: 17.1°N 85.1°W
    Moving: W at 16 mph
    Min pressure: 999 mb
    Max sustained: 60 mph

  7. Japan Meteorological Agency
    Tropical Cyclone Advisory #47 – 21:00 PM JST September 2 2020
    TYPHOON MAYSAK (T2009)
    =================================================
    100 km Northwest of Goto (Nagasaki Prefecture)

    At 12:00 PM UTC, Typhoon Maysak (950 hPa) located at 33.2N 127.9E has 10 minute sustained winds of 85 knots with gusts of 120 knots. The cyclone is reported as moving north northeast at 14 knots.

    Storm Force Winds
    ===================
    120 nm from the center

    Gale Force Winds
    ===================
    270 nm from the center

    Dvorak Intensity: T4.0

    Forecast and Intensity
    =======================
    24 HRS: 45.2N 126.4E – Extratropical Low Over land northeastern China

    ———————————————————-

    Tropical Cyclone Advisory #19 – 21:00 PM JST September 2 2020
    SEVERE TROPICAL STORM HAISHEN (T2010)
    =================================================
    West Northwest of the Northern Mariana Islands (Agrigan)

    At 12:00 PM UTC, Severe Tropical Storm Haishen (985 hPa) located at 19.6N 140.6E has 10 minute sustained winds of 55 knots with gusts of 80 knots. The cyclone is reported as moving west at 9 knots.

    Storm Force Winds
    =================
    50 nm from the center

    Gale Force Winds
    =================
    180 nm from the center

    Dvorak Intensity: T3.5

    Forecast and Intensity
    =======================
    24 HRS: 20.9N 136.8E – 80 knots (CAT 3/Strong Typhoon) Okinotorishima waters
    48 HRS: 22.6N 133.5E – 100 knots (CAT 4/Very Strong Typhoon) Sea South of Japan
    72 HRS: 25.1N 131.1E – 105 knots (CAT 5/Intense Typhoon) Sea South of Japan

  8. Gulf of Honduras is a very shallow body of water. The Gulf is very deep, thousands of feet so right off the Gulf of Honduras. Once you get into the Gulf of Honduras most is under 100ft deep. This is another spot that has helped intensify storms often. Hot shallow water is an enhancer. Harvey a good example. Even though Harvey had a TCHP of only 36, (90 typically for RI), the shallow waters likely helped in Hurricane Harvey’s rapid intensification. For the Gulf of Honduras, this intensification enhancer has an ugly history of some serious monster hurricanes. Link to Gulf of Honduras Marine Chart. http://www.gpsnauticalcharts.com/main/cb_gb_1573_0-gulf-of-honduras-nautical-chart.html

    1. Net heating around the core, studies suggest, if that heating gets disrupted rapid intensification can occur. Being in shallow water under 100 feet deep, after being in water thousands of feet deep, well I’d have to think that could cause a disruption in the heating around the core. Good study read here, the math is terrifying. Typhoon Hato RI’d in 2017 over very shallow waters, many examples out there. https://journals.ametsoc.org/jas/article/71/5/1623/27353/Hurricane-Eyewall-Evolution-in-a-Forced-Shallow

  9. Morning everyone….lots going on in the Atlantic basin today, but there is flash flooding potential closer to home (south-central US)….it’s not often, this time of year, that a “high” risk for flash flooding (rainfall) is issued for something not associated with a tropical system….but the combination of a trough over TX, frontal boundary to the north and high pressure to the south has done just that….

    https://www.wpc.ncep.noaa.gov/qpf/94ewbg.gif?1599048023232

  10. Hello, with some recent drought news:

    Germany’s Groundwater Wells Are Running Dry Amid Climate Crisis
    https://www.ecowatch.com/groundwater-wells-germany-run-dry-2647106696.html?rebelltitem=3#rebelltitem3

    Europe’s hedgehogs starving to death after long summer drought
    https://www.thetimes.co.uk/article/europes-hedgehogs-starving-to-death-after-long-summer-drought-xnkqc3p8m

    The trees helping German forests tackle climate change
    Mediterranean trees are being planted in German forests.
    Enter the South Hesse Oak Project: Years of summer heatwaves and minimal rainfall are damaging the country’s forests, with some native species like pine and oak struggling with the changing conditions.Researchers working on the project have had success planting downy oak trees, which normally grow in the Mediterranean and the south of France, in Frankfurt’s city forest …
    https://news.yahoo.com/trees-helping-german-forests-tackle-102330323.html

    Euro’s precipitation outlook for the next 10 days with me in the white zero-zone, again 🙁

    https://uploads.disquscdn.com/images/6d0711bb508f2908cf294c174c44908a8ae83534ae0d5a4fe96c0cd825879225.png

    1. I hope you get some rain.
      We just got 1/4 inch of rain after a three-week dry spell in Chicagoland.
      I’ll still have to water the gardens.

  11. A low pressure area is trying to form east of the windward islands near 12n 54w. This could be another yellow x and an invest. I suspect the wave coming off Africa will bbeanve 92L and the one east of the windwards will be 93L

  12. Watching storm radar, a Weather Channel app, shows it spinning up, but does not look like the eyewall is fully closed yet. And still not at 7:45 AM with the low center just north of Barra Patuca at that time, but it sure is woking on it hard RI.

    1. Look at the water vapor Loop, the diving low Levi talked about caught up with the unstacked upper level in the northwest blob, shoved the convection in the lower level of Nana southeast, and the Latest flight data shows Nana’s LL Low circulation in the upper right edge of the Southeast blob of convection. The radar shows the eyewall open at the top, filled in at the bottom like a C on the back. Looks even worse and less complete hours from now. Like sheer and close land there is going to disturb the intensification a bunch.

  13. Japan Meteorological Agency
    Tropical Cyclone Advisory #45 – 15:00 PM JST September 2 2020
    TYPHOON MAYSAK (T2009)
    =================================================
    60 km West Southwest of Goto (Nagasaki Prefecture)

    At 6:00 AM UTC, Typhoon Maysak (950 hPa) located at 32.1N 127.3E has 10 minute sustained winds of 85 knots with gusts of 120 knots. The cyclone is reported as moving north at 12 knots.

    Storm Force Winds
    ===================
    110 nm from the center

    Gale Force Winds
    ===================
    270 nm from the center

    Dvorak Intensity: T5.0-

    Forecast and Intensity
    =======================
    24 HRS: 42.5N 127.7E – Extratropical Low Over land northeastern China

    ——————————————————————

    Tropical Cyclone Advisory #17 – 15:00 PM JST September 2 2020
    SEVERE TROPICAL STORM HAISHEN (T2010)
    =================================================
    West Northwest of the Northern Mariana Islands (Agrigan)

    At 6:00 AM UTC, Severe Tropical Storm Haishen (990 hPa) located at 19.3N 141.4E has 10 minute sustained winds of 50 knots with gusts of 70 knots. The cyclone is reported as moving west at 8 knots.

    Gale Force Winds
    =================
    180 nm from the center

    Dvorak Intensity: T3.0-

    Forecast and Intensity
    =======================
    24 HRS: 20.8N 137.9E – 75 knots (CAT 3/Strong Typhoon) Okinotorishima waters
    48 HRS: 22.3N 134.6E – 100 knots (CAT 4/Very Strong Typhoon) Okinotorishima waters
    72 HRS: 24.6N 131.7E – 105 knots (CAT 5/Intense Typhoon) near Minami-daito island (Okinawa Prefecture)

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