Lance Bosart

Department of Atmospheric and Environmental Sciences University of Albany/SUNY

An Overview of Predecessor Heavy Rain Events Associated with Landfalling Tropical Cyclones

Room 811 AO&SS, September 21, 2009, 3:30 PM

Abstract

Predecessor heavy rain events (PREs) are rainstorms of at least 100 mm in 24 h that occur well in advance of landfalling and transitioning tropical cyclones (TCs). Cote (2007) identified 47 PREs associated with 21 TCs that impacted the eastern U.S. between 1998 and 2006 and noted that roughly one third of all landfalling and transitioning TCs in the eastern U.S. were associated with PREs. The typical PRE occurs approximately ~1000 km in advance of the TC, leads the TC by ~36 h, and lasts for ~12 h. PREs represent a forecast challenge because they are often associated with significant inland flooding. This presentation will provide an overview of PREs and the environmental factors that control their formation and evolution by means of climatological, composite and case study analyses.  Recent noteworthy PREs that impacted the central U.S. and produced significant inland flooding occurred in conjunction with Erin (2007), Ike (2008), and Rita (2005) will be discussed to illustrate the salient synoptic-dynamic processes that govern the structure and evolution of PREs.