Following the impacts of
Typhoon Bavi on the
Korean peninsula in August 2020, the
Korea Meteorological Administration (KMA) began to anticipate the
development of a new
tropical cyclone with the potential to be stronger and more damaging for the region than Bavi. The KMA assessed a high probability of the storm's development, but noted that its future impacts were uncertain; the
Joint Typhoon Warning Center (JTWC) also determined that there was a high likelihood of a "significant tropical cyclone" developing. Maysak's precursor disturbance was an
area of low pressure over the western Pacific east of the
Philippines. At 06:00
UTC on August 27, the
Japan Meteorological Agency determined that a nearly stationary
tropical depression had formed near 15°N, 132°E. The JTWC issued a
Tropical Cyclone Formation Alert for the system around the same time. The newly formed system was located in an environment conducive to storm development, including warm
sea surface temperatures and low vertical
wind shear. Clusters of
atmospheric convection emerged around the storm's center, comprising formative
rainbands wrapping into the developing circulation. Early on August 28, the
Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assessed the system as a tropical depression with the local name
Julian. At 06:00 UTC, the JMA assessed the tropical depression to have strengthened into a
tropical storm, assigning it with the name
Maysak. By this time,
outflow had become established and curvature of the Maysak's rainbands became apparent on satellite imagery. The storm's
cloud tops cooled substantially, indicative of further consolidation of its circulation. Maysak became a
severe tropical storm twelve hours later. Maysak became a typhoon by 12:00 UTC on August 29 according to the JMA after developing an
eye. The storm also began to move towards the north in response to a nearby
subtropical ridge. On August 30, Maysak's structure became indicative of an impending phase of
rapid intensification according to the JTWC. The typhoon developed a
central dense overcast that day with an eye embedded within. An approaching
trough over eastern China and western Japan caused Maysak to accelerate towards the north as it continued to traverse energetic ocean waters. The typhoon's eye became symmetric and spanned across. By 21:00 UTC, the eye had contracted to a diameter of . Around that time, the JTWC assessed the typhoon as having one-minute sustained winds of . At 00:00 UTC on September 1, the JMA determined that Maysak had ten-minute
maximum sustained winds of with gusts of up to . The associated
barometric pressure was estimated at 935
hPa (
mbar; 27.61
inHg). Maysak held this intensity as it began to move into a less conducive environment for storm development within the
East China Sea. Soon, Maysak began to weaken steadily as it passed the
East China Sea, slowing back down to a Category 3 storm. The storm then made landfall near
Busan,
South Korea at 02:20 KST on September 3 (17:20 UTC on September 2), with 10-minute maximum sustained winds at and the central pressure at 950 hPa equivalent into a Category 2 typhoon. After that, it crossed the
Sea of Japan and hitting
North Korea into
Jilin in
northeast China. Soon after, Typhoon Maysak transitioned into an extratropical low in northeast China. ==Preparations and impact==