Hurricane Matthew: An Ideal Setup for Catastrophic Flooding in Central North Carolina

Hurricane Matthew dumped a swath of 8 to 18 inches of rain across inland portions of eastern North Carolina during the period of 07 October through 09 October 2016. The extremely heavy rain produced several all-time one-day rainfall records, as well as widespread flash flooding and subsequent river flooding. Flooding associated with Matthew produced $1.5 billion in damage to 100,000 homes across North Carolina and left 98,699 structures across the state inundated with water.

Enhanced precipitation and the distribution of the heaviest rainfall associated with tropical cyclones (TCs) have been examined in numerous studies. Croke (2006), in collaboration between NC State University and several Mid-Atlantic National Weather Service Forecast Offices (NWSFOs), developed a conceptual model of a pattern favorable for enhanced precipitation due to the interaction of a TC with other meteorological features prior to landfall. This paradigm gives forecasters an indication of the potential for an enhanced precipitation event by identifying features that may exist at different temporal and spatial scales outside of the TC.

We will show that the synoptic and mesoscale patterns across the eastern United States prior to and during the time in which Hurricane Matthew impacted North Carolina fit this conceptual model for enhanced TC precipitation. Features consistent with the conceptual model included a strong upper level jet poleward of the tropical cyclone, an approaching upper trough, strong low-level moisture flux, a cold air damming region across the interior Piedmont, and a strong coastal front. Recognition of this developing pattern in the days leading up to the storm’s arrival allowed forecasters at the Raleigh, NC NWSFO to highlight the potential for anomalously high rainfall amounts and catastrophic flooding in forecast products prior to the storm.