Thursday morning temperatures are forecast to drop about 10 degrees Celsius from Wednesday, with parts of northeastern Gyeonggi Province and inland and mountainous Gangwon Province dipping below freezing. A cold wave advisory took effect at 9 p.m. Wednesday for most inland areas. It is issued from October to April when the morning low is forecast to fall at least 10 degrees from the previous day to 3 degrees or below and to run at least 3 degrees below normal. Morning lows on Thursday are forecast at 0 to 10 degrees nationwide. Frost will form in inland areas and ice in eastern Gyeonggi Provice, inland and mountainous Gangwon Provice, North Chungcheong Provice, northeastern North Jeolla Provice and inland central and northeastern mountainous areas of North Gyeongsang Provice. Daytime highs will stay between 14 and 19 degrees. Temperatures will swing by 15 degrees or more between morning and afternoon. Forecast lows and highs are 5 and 16 degrees in Seoul, 3 and 15 in Incheon, 3 and 17 in Daejeon, 8 and 17 in Jeonnam-Gwangju Special Metropolitan City, 5 and 17 in Daegu, 7 and 18 in Ulsan