Analysis of a rare snowstorm process in Altay regions, Xinjiang province

A heavy snow results in a rare snow disaster in the Altay region on 6-7 January 2010. Based on the conventional meteorological data, ECMWF products, T639 physical products at 00:00, 03:00 and 06:00 o’clocks, FY2E infrared satellite image and its brightness temperature data, the heavy snow process and its forming reasons were analyzed. The results show that circulation patterns are two troughs and one ridge with shape in the range of 500 hPa over the Asia and Europe. Circulation patterns, deep low vortex over Europe and Sayanling regions, strong blocking from the western Siberia to Taymyr peninsula and front zone in middle latitude are the large scale system for the heavy snow process. According to the surface weather chart, the heavy snow happens near the overlay area of warm front’ foreside of the Central Asian cyclone’ foreside and meso-scale shear line and convergence line in 850 hPa. The development and movement of cloud system are related significantly with snowfall in the high humidity and strong ascending areas. Changes of upper and lower jet as well as shear line and transportation of warm and wet airflow during the heavy snow could be revealed by the wind-time cross-section diagram of high level in single station. Variation of physical quantity in single station is indicative to snowstorm forecast.