Abstract: Based on the observational data collected from the tower in Tianjin, intensive automatic weather stations and the conventionally meteorological data, the characteristics of the easterly wind were analyzed before and after four snow events. The results show that the four events are all backflow-type snow. The water vapor source is provided by southwest air flow and low level easterly wind. Surface easterly wind is ahead of 8 hours before snowfall whose wind speed is about 2 m·s^-1 and is up to 12m·s^-1 at the 220 m height level. Easterly or southeasterly wind caused by northward low-pressure system from the south is relatively wet, while easterly or northeasterly wind caused by southward cold high pressure from the northeast is relatively dry. During the maximum snowfall period, the easterly wind at the tower layer increases significantly, while the ground wind speed changes insignificantly.

Key words: Easterly wind, Snowfall, Tower layers data, Backflow, Specific humidity