Synoptic and Large-scale Circulation Causes of Extreme Precipitation on the Southeast Coast of the Atlantic Ocean

Abstract

In this research, we analyzed synoptic and large-scale key to the non-hurricane related extreme precipitation over the SE US during 2015-2018 using MRMS product and ERA-5 reanalysis data. A region (the CGAR region: 31N to 36N, 80W to 72W) has been found to experience extreme rainfall with 600mm/day and above. The extreme precipitation in the CGAR region is likely due to strong and deep convection. A suitable atmospheric condition is discovered, i.e., an upper level (500 hPa) trough and a surface low located to the east of the trough. Three types of surface lows are associated with the cause of this extreme precipitation, the Gulf Stream Low, the Continental Low, and the Surface Low belt. The first two types of the low-pressure systems contributed to what percentage of deep convections. These results advance our understanding of extreme rainfall which potentially improve weather prediction in the region.