Analysis on the Predictability and Mesoscale Characteristics of "7.3"Short-time Heavy Rain in Chengdu

The "7.3" short-time heavy rainfall is appeared by the favourable background of large-scale circulation and meteorological element,there are some favorable conditions by analysis of the conventional observation;the observation data of the mesoscale convergence in surface automatic meteorological station has premonitory for the heavy precipitation,the surface observation data of the 'positive-negative' variable pressure show the gravity wave is the important factors for the mesoscale system.