Summer heat forecast to stretch into September

40 percent chance October will also be warmer than usual

Tourists explore Saebyeol Oreum on Jeju Island on Monday amid a heat wave advisory. (Yonhap)

South Korea’s heat wave alerts, in place nationwide for weeks, are expected to stretch into September, with a 60 percent chance temperatures will remain above the historical average, according to the Korea Meteorological Administration.

As of Monday, of the 183 regions nationwide, 182 saw heat wave alerts issued, as average nationwide apparent temperatures for the day reached 37 degrees Celsius as of 2 p.m.

Of the 182 regions that saw heat wave alerts, 133 were under heat wave warnings, and 49 were under advisories. In South Korea, a heat wave advisory is issued when the maximum apparent temperatures are forecast to exceed 33 C for at least two consecutive days, and a warning is issued when the maximum apparent temperature is forecast to exceed 35 C.

According to the KMA, temperatures were recently driven up by the hot and humid North Pacific high-pressure system and the hot and dry Tibetan high-pressure system dominating the atmosphere over the peninsula.

With such atmospheric conditions expected to last for the next few weeks, the state weather agency said the heat is forecast to last at least into September.

According to the KMA’s one-month outlook, it predicted that the first week of September carries a 50 percent probability of seeing temperatures higher than the historic average, with more than a 30 percent chance of seeing abnormally hot temperatures.

The chance of seeing higher-than-average temperatures in the second week of September is estimated at 60 percent, while the third and fourth weeks each carry a 50 percent likelihood.

The KMA added that there is also a 40 percent chance that above-average temperatures will last into October, as the high sea surface temperatures in the tropical western Pacific reinforce the circulation of high-pressure systems over the Korean Peninsula.

Though a warmer-than-usual October doesn’t necessarily mean that summer-like temperatures will last well into autumn, there is a slight chance that fall weather patterns will be affected by higher-than-average temperatures.

Warmer-than-average temperatures may also be observed in November, with an estimated chance of 40 percent. However, the KMA added that such predictions are subject to change depending on the development of the La Nina phenomenon and the reduction rate of sea ice in the Barents-Kara Sea.

Meanwhile, the KMA forecast heavy rain through Tuesday across the central region — including the Greater Seoul area, Gangwon Province, and North and South Chungcheong provinces — with 30 to 80 millimeters expected and up to 100 mm in Incheon and northern parts of Gyeonggi Province.

Other parts of the country, such as the North and South Chungcheong provinces, can expect rain ranging between 20 mm and 60 mm, while the southern parts of the country, including Busan and Jeju Island, may receive between 5 mm and 30 mm.

Although two days of rain could bring temperatures down slightly, the KMA stated that the drop in temperatures will not be enough to end the heat wave alerts. When the rain stops on Wednesday, the state weather agency said humidity levels will begin to rise, raising apparent temperatures.