From late July to mid August in 1995, the subtropical high moved northward, its power was very strong, and continued to move. It's strong south-west warm and humid gas flow in the rear moved Northward, the cold air carried by the Lake Baikal's low trough cold vortex in the East South set confrontation in Liaoning and Jilin Province, forming the strong convergence front with the low pressure within the quasi stationary front. And in the interaction between the two, frequent rainstorms had occurred in the most area of Liaoning province and the central area of Jilin province. The process of forming "95.7" flood in two major rainstorms weather is as follows:
On 24th~26th July, the cause of the rainstorm was as follows: the low trough in the East latitudes of the westerly belt met the strengthened subtropical high of the Western Pacific in the south of the northeast region, and the southwestern warm and wet air flowed on the north side of the subtropical high and the northwest cold air flowed in the south side of the low trough constitute a convergence zone in the eastern part of Liaoning Province. Because the subtropical high is obviously leaping to the West, the center is at 139 °E and 35 °N, which formed the high pressure dam in the East Coast. On the one hand, the formation of high pressure dam deepens and slows down the eastward westerly trough, on the other hand, it strengthens the low jet. In this way, the water is transported from the southwest to the northeast. At the same time, the cyclonic wave in North China was formed in July 25th, and along the rear of the subtropical high, it passes through the central and southern part of the northeast region, causing heavy rainfalls.
On 28~30th July, the cause of the heavy rain was as follow: the subtropical high is distributed in the East and West, in the mid latitudes from Mongolia to the northeast of China formed a relatively flat and broad low trough area, and strong westerly belt appeared at 40°N ~50°N, the central and southern part of the northeast region is located in the energy peak of the northern side of the subtropical high and the southern side of the west wind belt, the warm air on the north side of the subtropical high and the cold air in the back of the trough in the west wind belt met here, and the deputy high remain stable, moving slowly westward, a stable shear line is maintained near 120~130°N and 42°N at low level 85 thousand pa, and from the West Pacific Ocean through the East China Sea on the 85 thousand pa wind field, the warm and wet air in the Yellow Sea has been transported northward, thus the water and gas conditions are provided for the rainfall in the central and southern part of the northeast region. On the ground map, it was a broad depression from the north to the northeast, and a through in Hetao area-the ground system slowly moved eastward, thus the central and southern regions of Northeast China have been in the convergence zone of the wind field in the low pressure region, and the rain ended until the system finally moving east at 31th.
The information is provided by Disaster Risk Reduction Knowledge Service.
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