Comparative analysis on the medium and small scale characteristics of the "4.24" short-term rain and hail storms in Urumqi

A short-term rain and hail storm, respectively, occurred before the early morning and the evening on 24 April 2016 in Urumqi. Comparative analysis on the medium and small scale characteristics of the short-term rain and hail storms were made by using conventional data, NCEP reanalysis data with 1°×1°resolution, microwave radiometerdata, wind profile radardata, GPS atmospheric precipitation water vapor and satellite infrared cloud image. The results are as follows. (1) The short-term rain and hail storms were associated with eastward trough at mid-latitude on 500 hPa. Short-term rainfall occurred under the situation of 500 hPa westerly jet at the trough bottom and low-level north air flow. The hail occurred undert he situation of northwest stream jet which consistently exists in both low-and high levels. (2) The short-term rainfall was triggered by low-level jet, which providesa long distance water vapor transport. The low-level moistening before hail occurred was associated with the prior short-term rainfall, and the hail was triggered by the downward transport of low-level jet. (3) Both the short-term rain and hail storms occurred where TBB has maximum gradient. Abnormal updraft within the hail cloud was stronger.Its temperature and water vapor density profiles rised more dramatically than those in the short-term rain storm.