A Case Study of Continuous Torrential Rain in Guangdong during the Pre-flood Period in 2009

A continuous torrential rain case in the middle-west coastal areas of Guangdong from May 23rd through the 24th 2009 is analyzed using conventional ground-based observations and soundings,as well as unconventional data such as automatic weather stations,satellite products,and NECP/NCAR 1°×1° 6-hourly reanalysis data.The results are shown as follows: the characters of this torrential rain case are long duration,strong intensity,and area-concentrated with significant meso-α scale atmospheric motion;South China Sea mesoscale eddies and low-level jet moved northward quickly while the western pacific subtropical high maintained stable;There was favorable convergence coincident with the torrential rain area on the north flank of mesoscale eddies;The confluence of southwest monsoon flow from Bengal Bay and cross-equatorial flow from Somali and the area near 110oE came into a strong and narrow conveyer belt to transport sufficient moisture and unstable energy to the torrential rainfall areas;There were two mesoscale convective complexes(MCC) developing violently and resulting in the torrential rain;And the high-level circulation kept the MCCs quasi-stationary over the west of the Pearl River estuary.