typhoon activity has become frequent since september, and the successive typhoons have made people feel the extreme changes in autumn weather. for example, at 9:45 p.m. on september 19, typhoon prasang landed in fengxian, shanghai. this is the first time in meteorological records that two typhoons have landed in shanghai within four days. not long ago, typhoon bebejia became one of the strongest typhoons to land in shanghai since the founding of the people's republic of my country.

1. quasi-typhoon approaches my country again

on september 21, this year's 14th typhoon prasang gradually degenerated into a temperate cyclone in south gyeongsang province, south korea at night. the central meteorological observatory stopped numbering it at 20:00 on the 21st. however, it can be seen from the satellite cloud map that after typhoon prasang was transformed into a temperate cyclone, there were still large areas of thick cloud activities in the south china sea and the western pacific. this is because the recently active monsoon trough continues to hover over the sea, brewing new impacts.

the latest dynamics show that the tropical depression system located in the northern coast of taiwan island will become the protagonist of the weather stage on the evening of september 21. although typhoon "prasang" transformed into an extratropical cyclone in southern south korea on september 21 and stopped being numbered, the monsoon trough system that successively gave rise to typhoons bebejia, prasang and soulik is still active and has generated a new tropical depression, which is gradually approaching the southeast coast of my country.

at the same time, the cold front is not to be outdone and is rapidly moving southward. the collision of the southward cold front and the tropical depression will undoubtedly bring large-scale autumn rainstorms to the coastal areas of fujian and guangdong. the complexity of this phenomenon lies in the fact that the cold front and the tropical system act at the same time, causing the rainfall in the southeast coastal areas to become more intense, and heavy rains follow.

2. there will be large-scale autumn rainstorms in fujian and other places!

rainfall in the eastern coastal areas of fujian began on the evening of september 21. according to the forecast of the central meteorological observatory, from september 21 to 25, there will be moderate to heavy rain in the eastern and southern parts of jiangnan, and the eastern and southern parts of south china, with heavy rain in some areas and local torrential rain. the current forecast shows that some areas along the southeast coast will face continuous heavy rain, and the local rainfall may exceed 400 mm. especially in the coastal areas of fujian, the intensity and duration of the heavy rain will reach a peak.

the main reason behind this weather phenomenon is the northward movement of the monsoon trough and the intersection of cold air. the low-temperature air mass brought by the cold air further expands the rainfall range. the tropical depression is located in the active area of ​​the monsoon trough and has sufficient water vapor supply, which provides conditions for its continued strengthening and heavy rainfall.

due to the continued heavy rainfall, some coastal areas of fujian and guangdong may face flooding,landslidesecondary disasters such as landslides and landslides will occur. especially in mountainous areas and low-lying areas, the risk of geological disasters is relatively high. long-term rainfall will make the soil saturated and easily induce landslides. therefore, in the next three days, local residents need to pay special attention to weather changes and try to avoid entering dangerous areas.

in addition to the rainstorms in the southeastern coast, the southward movement of cold air has significantly affected the central and eastern regions of my country. on the morning of september 21, the temperature in northeast china and north china hit a new low in the second half of the year. among the provincial capitals and municipalities, harbin had a minimum of 3.1 degrees, hohhot had 4.1 degrees, changchun had 6.2 degrees, shenyang had 8.8 degrees, tianjin xiqing had 12.5 degrees, beijing had 12.9 degrees, jinan had 13.5 degrees, taiyuan had 13.7 degrees, shijiazhuang had 15 degrees, and zhengzhou had 17.4 degrees. the temperature in the greater khingan range fell below freezing, with the lowest temperature at the tuli river national station at -10.4 degrees. winter is rapidly moving southward. the temperature in northeast and north china has hit a new low in the second half of the year. among the provincial capitals and municipalities, harbin has a minimum of 3.1 degrees, hohhot has 4.1 degrees, changchun has 6.2 degrees, shenyang has 8.8 degrees, tianjin xiqing has 12.5 degrees, beijing has 12.9 degrees, jinan has 13.5 degrees, taiyuan has 13.7 degrees, shijiazhuang has 15 degrees, and zhengzhou has 17.4 degrees. the temperature in the greater khingan range has fallen below freezing, with the lowest temperature at the tuli river national station at -10.4 degrees. winter is rapidly expanding southward. for many places south of the great wall, it marks the full start of the autumn mode, and the hot weather is gradually retreating under the impetus of this round of cold air.

in general, from september 21 to 24, fujian, guangdong, hainan and other places will be the "main battlefield" of heavy rain, especially in the coastal areas of fujian, where the rainstorms will be strong and last for a long time. it should be noted that the combination of monsoon trough and cold air makes it difficult to predict the rainfall in advance, but the scale and impact range of the rainstorm are large, and local residents should take precautions.

the interweaving of typhoon activity and cold fronts makes the weather in late september changeable and complicated. although we cannot predict when every drop of rain will fall, the large-scale rainfall situation is very clear. residents in the southeast coastal areas should pay close attention to the weather forecast in the next few days to ensure that they can safely get through this autumn rainstorm. in short, the aftermath of the typhoon season has not yet dissipated, and the advancement of cold fronts has made the weather even more unpredictable. in the next few days, the wind and rain will continue in the southeast coastal areas, so everyone must be vigilant.