Analysis of a Snowstorm Weather Process in a Coexisting Warm Area and Cold Front in Northern Xinjiang

This study compared and analyzed the causes of snowstorm weather during 30-31 January 2014 in northern Xinjiang, using the routine and high spatiotemporal resolution ECMWF fine-grid data, FY-2E infrared image, and NCEP FNL data. The findings suggest that the direct impact system of the process was a shortwave trough moving east that met north and south frontal zone. The southwest low level jet brought a large quantity of water vapor from the Atlantic. In front of the shortwave trough, the lower troposphere, mesoscale convergence system and upper divergence overlapped, providing strong upward movement for snowstorm weather. The warm snowstorm occurred in the pressure decompression heating area, but the opposite was the case in the cold front area. The cold front snowstorm area featured strong convective unstable stratification, but the warm area was weaker. The warm snowstorm area was located within northern mesoscale cold high pressure. The largest area of the gradient was in the rear positive vorticity area and the front negative vorticity area, but the cold front snowstorm area was in the positive vorticity area. βscale cold high pressure formed near Ebinur Lake due to the topographic effect. The results provide a new indicator to forecast snowstorms in northern Xinjiang.