Analysis on the Process of a Convective Rainstorm of Stationary Front Triggered by Weak Cold Air

Abstract

Based on the conventional meteorological data and the NCEP/NCAR 1 &#176 × 1 &#176 reanalysis data and those related to mid-scale automatic station, satellite cloud picture and radar return, with the dynamic diagnosis analysis method, an analysis is made on the process of the convective rainstorm of quasi-stationary front triggered by the weak cold air on June 4-7, 2014, showing: 1) the process occurred in the event of convection of a stationary front triggered by the eastward moving south trough and the southward moving weak cold air from west under the background of circulation of two ridges and one trough at the Asian-European mid-high latitude and weakening and southeastward moving subtropical high; 2) a system configuration that contributes to convective rainstorms formed in the event of the convergence of low-level moisture, upper-level divergence and the continuous vertical ascending motion after the 200 hPa upper-level jet stream moved westwards from east and the 850 hPa southwest jet stream intensified; 3) after the intrusion by weak cold air of the meso-scale katallobaric area formed by the accumulated warm moist air of Guangxi before the intrusion, the warm moist air rose to trigger convection; convection cells developed and spread nearby the boundary between anallobaric area and katallobaric area, during which total 5 MCSs developed and each formed a rainstorm center at the part where the MCSs coincide; a meso-scale katallobaric area forms and develops 2 - 5 hours earlier than convection, so that it is also a warning of heavy rains.