High score! Who can help me analyze this 700 hectopascal weather process map?

The chart is too small to have a date and time, so it is difficult to analyze.

This strong cold air accumulated a lot of cold air from Siberia cold high pressure, and then it went south to affect Chinese mainland, and the temperature in the northern region (including Xinzhou City) dropped significantly.

The picture shows 165438+ 10/3 Today, 06: 00 international time (Beijing time 12)700? Weather chart in hectopascals