Seoul morning temperature drops to 10.2 C amid 15-degree daily swings; cold wave advisory issued for Gangwon mountain areas Monday night

A pedestrian hurries through Gwanghwamun Square in Seoul on Tuesday as chilly morning weather grips the country. [Yonhap]
A pedestrian hurries through Gwanghwamun Square in Seoul on Tuesday as chilly morning weather grips the country. [Yonhap]

Temperatures dropped sharply during the morning commute Tuesday amid cold wave advisories issued for some parts of the country as early as the beginning of October. Cold air pushing down from the northwest sent morning readings falling, and strong winds drove the wind chill even lower.

According to the Korea Meteorological Administration, temperatures as of 6 a.m. Tuesday had fallen to 1.0 C at Wangsan in Gangneung, Gangwon Province, with Daegwallyeong in Pyeongchang recording 1.6 C, Mahyeon in Cheorwon 1.9 C, and Panmunjeom in Paju, Gyeonggi Province, 2.5 C. Baekun in Jecheon, North Chungcheong Province, dropped to 2.8 C, while Bukhu in Andong, North Gyeongsang Province, fell to 2.3 C.

Seoul's morning temperature stood at 10.2 C. Other major cities also recorded a chilly start to the day — Suwon at 8.5 C, Incheon at 12.7 C, Daejeon at 10.3 C, Cheongju at 11.1 C, Gwangju at 12.0 C, and Busan at 14.4 C.

The cold was driven by a mass of frigid air descending from the northwest. Cold northwesterly winds blowing along the edge of a high-pressure system centered near central China, combined with active radiative cooling under clear skies, caused temperatures to fall sharply.

Strong winds were expected to persist across most of the country through Tuesday morning, pushing the wind chill well below the actual air temperature.

The cold snap is forecast to continue through Thursday. Morning lows are expected to fall about 5 degrees below Monday's readings by then, with some mountain areas of Gangwon Province seeing drops of around 10 degrees — bringing inland temperatures nationwide to around 10 C and Gangwon inland and mountain areas to 5 C or below.

Afternoon highs are expected to rebound to around 20 C, creating a wide daily temperature swing. Daytime highs of 20 to 24 C are forecast for Tuesday and 21 to 25 C for Wednesday, with the gap between daytime and nighttime temperatures expected to reach around 15 degrees.

"Through Wednesday, South Korea will continue to see an inflow of cold northerly winds as a high-pressure system moves eastward from central China," Korea Meteorological Administration forecaster Kim Chae-yeon said. "Morning temperatures will remain low on Wednesday as well, and the large gap between daytime and nighttime temperatures will persist."

Ice is expected to form in some Gangwon mountain areas Tuesday and Wednesday, and frost is forecast for parts of Gangwon's inland and mountain regions as well as the northeastern mountain areas of North Gyeongsang Province.

The KMA issued a cold wave advisory for the Taebaek and Pyeongchang mountain areas of Gangwon Province at 9 p.m. Monday. It is the earliest cold wave advisory issued anywhere in the country since the current cold wave warning system was established in 2005 — about 20 days earlier than last year.

Winter temperatures expected to stay above seasonal norms

A chart from the Korea Meteorological Administration showing the relationship between high sea surface temperatures in the western Indian Ocean and temperature and precipitation trends on the Korean Peninsula. [Korea Meteorological Administration]
A chart from the Korea Meteorological Administration showing the relationship between high sea surface temperatures in the western Indian Ocean and temperature and precipitation trends on the Korean Peninsula. [Korea Meteorological Administration]

Whether this cold snap will translate into a harsh winter is a separate question. The KMA said it is difficult to predict winter weather based solely on the early October temperature drop, as the current cold spell is a temporary phenomenon caused by a southward push of cold air from the northwest.

The KMA's three-month outlook forecasts above-normal temperatures for October through December. High sea surface temperatures in the western Indian Ocean could influence atmospheric circulation, increasing the likelihood of warm, moist southwesterly winds reaching the Korean Peninsula. From November to December, El Niño effects may strengthen high-pressure circulation east of Japan, further raising temperatures on the peninsula, the KMA said.

"In summer and winter, the weather is dominated by specific air masses such as the North Pacific high and the Siberian high, but we are now in a transitional period between seasons," said Woo Jin-gyu, a KMA communications officer. "Rather than being under the influence of a particular air mass, this is a period when high- and low-pressure systems passing over the Korean Peninsula take turns affecting the weather."


newday@heraldcorp.com