Diagnostic Analysis of a Persistent Rainstorm on May 7 to 10,2013 in Yongzhou

Using the data of conventional observation,NCEP / NCAR 1° × 1° reanalysis and regional observation stations,we diagnostically analyzed the synoptics,dynamics and thermodynamics of a persistent rainstorm on May 7 to 10,2013 in the Yongzhou area. The result is presented as follows. The rain resulted from a joint effect of an upper-level trough,jet streams at both upper and low levels and a warm,inverted trough that was followed by weak cold air. A wet layer was deep during the rain,sharp rise and fall of specific humidity may indicate the occurrence of relatively intense episodes during a rainstorm. The height to which vertical velocity develops and the area it covers are somewhat related with the amount of rain. The thermodynamics indexes of K,SI and CAPE are well corresponding to intense rainfall.