今天上午北京大部分地区有小雪，西部、南部部分地区降雪更明显

Group 1 - On January 17, 2023, Beijing experienced uneven snowfall, with significant accumulation in areas such as Fangshan, Mentougou, Shijingshan, and Haidian, ranking among the top in the country for precipitation during the same period [1] - The average snowfall in Beijing from 06:00 on January 17 to 08:00 on January 18 was 1.2 mm, with an average of 1.6 mm in urban areas; the highest recorded snowfall was 9.9 mm in Fengtai District [1] - A yellow warning for road icing and sustained low temperatures has been issued, advising caution for cold weather and traffic safety [1] Group 2 - From January 18 to 21, a cold wave is expected to bring significant temperature drops and increased precipitation across central and eastern regions of China, with average daily or minimum temperatures expected to decrease by 6 to 12 degrees Celsius [2] - Certain areas, including parts of Huanghuai, Jianghuai, Jianghan, and Jiangnan, may experience temperature drops of 12 to 14 degrees Celsius, with localized drops exceeding 16 degrees Celsius [2] - Heavy snow or blizzards are anticipated in provinces such as Shaanxi, Henan, Shandong, Hubei, Anhui, and Jiangsu, while freezing rain may occur in parts of Henan, Hubei, Hunan, Guizhou, and Chongqing [2]