Read the schematic diagram of the position of the ground weather system at a certain moment in China and complete the following questions. (1)M The weather system is _ _ _ _ _. At this time, Beijing and Urumqi.

(1) According to the front symbol at m, it can be judged that the weather system is a cold front; Urumqi is controlled by high pressure, and the downward flow prevails. The weather is fine, and Beijing is behind the cold front, and the weather is rainy.

(2)M is a cold front. When the weather system passes through Dalian, there are often strong winds, rain, snow and cooling.

(3) On the isobar diagram, the specific wind direction is from high pressure to low pressure, the northern hemisphere deflects to the right, and the Xi 'an wind direction is northeast wind; Wind power depends on the density of isobars. The denser the isobar, the greater the wind force, the thinner the isobar and the smaller the wind force. Among Fuzhou and Harbin, Harbin has the strongest wind.

(4) It is a cyclone (low pressure center) that controls the appearance of front on the trough line of Shanghai weather system.

So the answer is:

(1) cold front? Beijing

(2) gale, rainstorm, snow (rainy day) cooling

(3) Harbin in the northeast of China

(4) Low pressure (cyclone or frontal cyclone)