Poster Session P3.15 The April 28, 2008 Southeast Virginia Historic Tornado Outbreak

Monday, 27 October 2008
Madison Ballroom (Hilton DeSoto)
Bryan Jackson, NOAA/NWSFO, Sterling, VA; and J. Billet

Handout (2.4 MB)

On April 28, 2008 severe thunderstorms developed ahead of a cold frontal boundary and crossed the Mid Atlantic region producing 11 tornadoes in southeast Virginia, including one that produced EF-3 damage in Suffolk, VA. The tornadoes originated both from discrete supercell thunderstorms and Quasi-Linear Convective System (QLCS) thunderstorms. This event is of particular note because the entire Wakefield County Warning Area (CWA) had cloud ceilings of one thousand feet or less from the day prior to the event through midday of the event. In fact, the skies remained overcast through convective initiation, which produced weak environmental lapse rates aloft and held surface-based Convective Available Potential Energy (CAPE) estimations to generally below 1500 J kg-1. The severe threat had been minimized from both the local and national perspectives due to fact that the skies had not broken in advance of the front by mid-morning of the 28th.

The primary data analysis will focus on the synoptic and mesoscale thermodynamic and dynamic environmental conditions from the day prior to and through the event, as well as radar data during the event. The goal of this study is to determine how such a historic tornadic outbreak occurred despite limiting factors such as cloud cover, low surface temperatures, and limited CAPE. Special attention will be paid to the supercell that developed in northeast North Carolina and produced a major tornado that tracked from Suffolk to Norfolk, Virginia. Also, comparisons will be made between this event and the La Plata, Maryland tornado of April 28, 2002 and other low CAPE, high shear tornado events.

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