特别提醒想要"追雪"的市民朋友，20日夜里衢州主城区有较大概率出现纯雪，虽然总体量级不大。上一 次衢州主城区出现纯雪是2024年1月，已经时隔两年。 21日至23日低温冰冻加剧。雨雪渐止后，降温效应全面凸显，大部分地区最低气温降至-1℃~-3℃，山 区低至-4℃~-6℃，全市将出现冰冻或严重冰冻天气，直至本周末寒潮影响结束，气温才会逐步回升。 雨雪天路滑、夜间气温低易结冰，驾车请减速慢行；户外需防范大风刮落物，山区出行尽量避开陡坡路 段。同时，低温天气需注意用电用火安全，防范电力设备和供水设施冻裂，保障居家生活正常。 "窗外灰蒙蒙一片，到底是雾还是霾？"昨日清晨不少市民发出疑问。气象专家解释，雾和霾的核心区别 在于相对湿度与成分：雾是水汽凝结形成的微小水滴，相对湿度大于90%，呈乳白色且潮湿感明显；霾 则是灰尘、污染物等干微粒聚集形成，相对湿度小于80%，颜色偏混浊暗沉。监测数据显示，昨日早晨 市区相对湿度未达雾的形成标准，因此判定为霾。不过随着夜间雨雪天气到来，空气湿度将显著上升， 霾天气会逐步消散，空气质量也将改善。 本报讯 （记者 陈霞） 刚感受完20℃+的日间暖意，强寒潮已"整装待发"。记者从市气象部 ...

Core Viewpoint - The article discusses a significant temperature increase in the central and eastern regions of China, with some areas breaking historical records, followed by a forecasted sharp drop in temperatures due to incoming cold air [1]. Weather Forecast Summary - On December 19, temperatures in Nanjing reached over 20°C, significantly higher than the usual 10°C for mid-December, marking a record high [1]. - A cold air mass is expected to move from north to south, leading to a "cliff-like" drop in temperatures across most of the central and eastern regions, returning to seasonal averages [1]. - A blue cold wave warning has been issued for Jiangsu Province, predicting a temperature drop of 8-9°C in certain areas and 6-7°C in others from December 20 to 22 [1]. - The lowest temperatures are anticipated on the morning of December 22, with northern areas potentially reaching around -2°C and localized frost expected [1]. Precipitation and Drought Conditions - Jiangsu has been experiencing below-average precipitation, with southern regions facing moderate to severe drought conditions [1]. - Light rain is expected in some areas south of the Huai River on December 20, but the rainfall is likely to be insufficient to alleviate drought conditions, serving only to slightly moisten the environment [1]. - Additionally, fog and haze are forecasted for December 20, necessitating public health precautions, with improvements expected after December 21 [1].

Summary of Key Points Core Viewpoint - The article discusses the recent weather conditions in China, particularly focusing on the occurrence of dense fog in several regions, the expected changes in weather patterns, and the implications for air quality and temperature fluctuations. Group 1: Weather Conditions - Multiple regions including Beijing, Tianjin, Hebei, Henan, Shandong, Jiangsu, Anhui, and Hubei experienced dense fog, with visibility dropping below 50 meters in areas like Tongzhou, Dezhou, Shangqiu, Bengbu, and Huainan [1][3] - A red alert for fog was issued in Julu County, Hebei, indicating severe visibility issues [3] Group 2: Future Weather Predictions - Following the fog, the weather is expected to improve due to sunlight and weak cold air, with no significant smog forecasted for the next few days [3] - However, from November 4 to 7, the air quality in North China and the Huanghuai region is predicted to deteriorate again, leading to the return of fog and haze [5] Group 3: Temperature Trends - The temperature in central and southern North China is currently around or above 20°C, marking a recent high [8] - A significant drop in temperature is anticipated next week due to a strong cold air mass, with expected decreases of 4 to 8°C in many areas, and localized drops exceeding 10°C [8] Group 4: Rainfall and Flood Risks - From November 2 to 4, heavy rainfall is expected in the eastern Southwest, central and southern Jiangnan, eastern Guangxi, western Guangdong, and Hainan, with cumulative precipitation reaching 30 to 80 millimeters, and localized areas in Yunnan and Hainan potentially exceeding 200 millimeters [9][13] - The rainfall may lead to significant flooding risks in certain regions, particularly in Yunnan and southern Sichuan, where the rainfall could surpass the total for the entire month of October [13] Group 5: Tropical Weather Developments - The Japan Meteorological Agency has classified a tropical disturbance east of the Philippines as a tropical depression, which is expected to develop into Typhoon "Haigui" by November 5, with potential impacts on the South China Sea [14]

Group 1 - A new cold air mass has arrived, primarily affecting northern regions of China, while southern areas remain warm with temperatures reaching around 30°C in places like Guangdong and Hainan [1][3] - Northern cities such as Changchun and Shenyang are expected to experience their lowest temperatures of the year, with highs of 4°C and 8°C respectively [3] - The overall trend for the coming days indicates a gradual warming in the central and eastern regions of China, with temperatures expected to return to normal or slightly above normal levels after October 28 [3] Group 2 - Fog and haze are anticipated in northern regions during the intervals between cold air impacts, particularly affecting areas like southern Hebei and most of Shandong [5] - Historically, from September to February, northern China experiences a significant number of foggy days, with cities like Shijiazhuang and Tianjin seeing over 80% of their annual fog days during autumn and winter [5] - Snowfall is expected in northeastern Inner Mongolia and northern Heilongjiang due to the new cold air, with localized heavy snow possible [6] Group 3 - The southwestern region of China is forecasted to have frequent rainfall in the last days of October, particularly in areas like Sichuan and Yunnan, with precipitation expected over 4 to 7 days [6]

Summary of Key Points Core Viewpoint - The Central Meteorological Administration forecasts significant cold air impacts across various regions in China, including Inner Mongolia, Northeast China, North China, and the Huanghuai area, leading to strong winds and temperature drops [1][4]. Group 1: Weather Forecast - From October 25 to 26, areas such as eastern and southern Qinghai, northern and eastern Tibet, and central and southern Gansu are expected to experience light to moderate snow or sleet, with some regions facing heavy snow and local blizzards [1]. - Starting today until October 27, cold air will affect central and eastern Inner Mongolia, Northeast China, North China, and Huanghuai, with wind speeds of 4 to 6 levels, gusts reaching 7 to 8 levels, and localized gusts up to 9 levels [4]. - Temperature drops of 4 to 6 degrees Celsius are anticipated in some areas, with local drops exceeding 8 degrees Celsius [4]. Group 2: Visibility and Air Quality - Prior to the cold air impact, areas in North China and Huanghuai will experience fog and haze, with significant visibility reductions in regions such as southern Hebei, southern Beijing, and central Shaanxi [4]. - This morning and into the afternoon, heavy fog is expected in southern Hebei, southern Beijing, and central Guizhou, with visibility potentially dropping below 200 meters in some areas [4].