Contrast Analysis of Two Squall Lines in Huanghuai Region of China

The two squall lines happened in Huanghuai region of China on 17 July 2009 and 19 July 2010. The conventional and non-conventional data including radar data, sounding data, auto-weather-station, significant weather report etc. are used in this paper, to contrast and explore the genesis conditions and mechanisms for the two squall lines. The results show that the two squall lines both occurred ahead of trough at 500 hPa. There is frontal passage beyond the ground surface. The southerly jet stream exists in low level. Further dry line lies at the north of the Shandong Province in the low level. The PWAT is larger than 50 mm. Of course there are different in these two processes. Vertical wind shear is larger on 7 July 2009 than that on 19 July 2010. While Shandong Province lies under the crossing of high and low jet stream on 19 July 2010. The high wind and short duration heavy rain occurred easily under this pattern。There are different reasons for hail not happened. For the squall line occurred on 17 July 2009, the 0℃ level is high, while for the other one, the CAPE is smaller. These results can help us to forecast the squall line better in Huanghuai region of China.