Rain, thunderstorms forecast for central region amid atmospheric instability
Showers, strong winds and possible hail are forecast through Thursday in Seoul and other central regions, while the south and Jeju stay mostly clear.
Rain and scattered showers are expected across the greater Seoul area, Gangwon, Chungcheong and North Gyeongsang through Thursday, according to the Korea Meteorological Administration (KMA).
Forecast precipitation totals are 5 to 20 millimeters (0.2 to 0.8 inches) in Seoul, northern Gyeonggi and southeastern Gyeonggi on Wednesday evening; 5 to 30 millimeters in inland and mountainous areas of Gangwon; 5 to 20 millimeters in northern parts of the Chungcheong region and about 5 millimeters in inland northern areas of North Gyeongsang.
Southern regions and Jeju Island are expected to remain mostly clear.
Scattered showers are forecast for Thursday as well, with expected rainfall of 5 to 30 millimeters in Seoul and inland Gyeonggi.
On Thursday, around 5 to 40 millimeters of rain is expected to drench inland and mountainous Gangwon; 5 to 30 millimeters in Daejeon, Sejong, inland South Chungcheong and North Chungcheong; and 5 to 20 millimeters in northeastern North Jeolla and inland and mountainous areas of northern North Gyeongsang.
"Areas affected by the rain could see strong winds, thunder, lightning and hail,” said Cho Kyung-mo, a senior KMA forecaster. “People should take precautions to prevent property damage and avoid safety hazards.”
The rain expected on Wednesday is expected to develop as warm, moist air crossing the Yellow Sea collides with cold air in the upper atmosphere, according to the weather agency.
The Korean Peninsula has been under the influence of a trough passing to the north as of Wednesday. It creates favorable conditions for warm, humid air carried by westerly winds to rise above. When that air mass encounters colder air aloft, atmospheric instability can intensify. It can also trigger thunderstorms and hail.
Cold air with temperatures around minus 19 degrees Celsius (minus 2.2 degrees Fahrenheit) is currently affecting the peninsula from roughly 5 kilometers (3.1 miles) above the surface in the northern parts of the Korean Peninsula.
The showers forecast on Thursday will develop under somewhat different conditions. While the trough responsible for Wednesday’s rain is expected to move eastward, Korea will come under the edge of a high-pressure system centered near Shanghai. It will allow strong sunshine to heat the surface during the day.
With the cold air aloft not yet fully retreated and the lower atmosphere warming under direct sunlight, a large temperature contrast between the upper and lower levels is expected to appear.
As a result, brief showers lasting 30 minutes to an hour are expected mainly across inland areas, where rising air currents are more likely to form.
“Rainfall amounts could vary significantly even within the same region,” a KMA representative said.
The influence of cold air in the north has also brought relatively cool conditions to the central parts of the country.
Seoul’s daytime high reached 25.3 degrees Celsius on Sunday, 25.1 degrees on Monday and 24.8 degrees on Tuesday, all of which had remained near or slightly below seasonal averages. On Thursday, morning lows are expected to range from 13 to 17 degrees Celsius, while daytime highs are forecast to stay between 24 and 27 degrees Celsius.
Cloudy skies are expected across much of the country from Saturday to next Wednesday. Jeju Island is forecast to see rain from Sunday afternoon through Monday morning.
BY HEO JEONG-WON [[email protected]]
