The indicative effect of the wind field at the Mount Nanyue and Mount Lu stations on the plum rain front rainstorm in the Yangtze River Basin

In this study, we analyze how wind evolution influences the plum rain front rainstorm by using the observational data of wind field at Mount Nanyue and Mount Lu from June 1th to July 31th during 2005-2013, the NCEP/NCAR global reanalysis data (1°×1°)during 1990-2013, as well as conventional sounding data and automatic station rainfall data. There are two types of synoptic systems in the plum rain front over the Yangtze river. The common points are as follows. There are strong southerly jets in the middle and lower levels. The intensity of the heavy rain corresponds to the intensity of low level jet. When the southwesterly wind on Mount Nanyue increases to 12 m·s^-1 or more and the southerly flow on Mount Lu significantly increases to 8 m·s^-1 or more, there will be regional heavy rain in the Yangtze river basin. Southerly flow that maintains different velocity for three consecutive hours on Mount Nanyue and Mount Lu has a good relationship with the rain belt of plum rain front. Moreover, the southerly flow can predict rainfall area in 2-8 hours advance. So, it will be a good index for rainfall area forecast.