Updated 11/16/08 to add a link to the research paper written about this event.
"Ides of March" Tornado Outbreak - March 15, 2008
A mesoscale convective system (MCS) moved across northern Georgia and upstate South Carolina during the early morning of Saturday, March 15. The MCS then evolved into a quasi-linear convective line that pushed southeast across southern South Carolina and southeast Georgia ahead of a cold front. Numerous reports of large hail and tornadoes, along with many injuries, were received across southern South Carolina and parts of Southeast Georgia. NWS Charleston damage survey teams found that 3 EF-1 and 3 EF-2 tornadoes struck southern South Carolina and Southeast Georgia. Click here for the public information statement detailing the 6 confirmed tornadoes. All of the Local Storm Reports across the Charleston County Warning Area (CWA) can be found here while a map of all of the reports across the Southeast U.S. can be found here.
Rarely do the coastal Carolinas and southeast Georgia experience the dangerous combination of an extremely sheared wind environment along with steep mid-level lapse rates and volatile surface-based instability. Couple these factors with a strong upper-level disturbance moving into the southern Mid-Atlantic region and the stage became ripe for classic supercell development.
An ominous indication of the potential shear and mid level instability was evident during the evening of Friday, March 14 when isolated supercells developed over north Georgia producing a series of tornados including a fatal EF-3 in Polk and Floyd Counties and an EF-2 in metro Atlanta. These cells moved southeast into the central Savannah River area after midnight while weakening. This activity was followed by a rapidly moving MCS which tracked eastward through Mississippi and Alabama overnight. Severe thunderstorms rolled into parts of north Georgia and the South Carolina upstate after dawn before weakening.
When the dawn arose across southeast Georgia and the eastern Carolinas, there was evidence that an unstable mid-level environment had worked into the midlands. Low stratus which earlier forecast models had suggested being widespread across the region; were confined to the immediate Gulf Coast region and only pockets of stratocumulus were noted over the coastal and piedmont areas. Surface heating during the morning and early afternoon hours greatly contributed to the impressive deep-layered instability which preceded the band of supercell thunderstorms across the northern half of southeast Georgia and along the Interstate 95 corridor in eastern South Carolina.
At 1800Z (1 PM EDT), a linear band of thunderstorms was developing on the downwind flank of the previous MCS which had weakened late in the morning over the South Carolina upstate and North Carolina Mountains (see 1815Z IR satellite image). By 2115Z (415 PM EDT), the line had developed further and pushed into central SC (see 2115Z IR satellite image). Around this time, the NWS Storm Prediction Center issued a Potentially Dangerous Situation (PDS) Tornado Watch / (text) from southern North Carolina through central GA, including southern South Carolina. An ill-defined surface warm front analyzed around midday along the North and South Carolina border was initially forecast by numerical guidance to be the main low-level forcing mechanism with the impending shortwave. This feature at the surface became secondary to a new convectively induced surface low to the west of Augusta, Georgia in the mid afternoon. Strong pressure falls developed from the Altamaha River region of southeast Georgia northward over most of eastern South Carolina between 1800Z (1 PM EDT) and 2200Z (5 PM EDT). Wind fields were increasing ahead and to the south of the main shortwave diving into the North Carolina Piedmont with 0-1 km helicities as high as 500-600 m2/s2 developing along the Interstate 95 corridor. With mid-afternoon Convective Available Potential Energy (CAPE) values from 1400-2000 J/KG, Energy Helicity Index (EHI) values were between 3 and 5 along this axis. At the same time, analyzed Lifted Indices (LI) between Augusta, Georgia and Statesboro, Georgia reached -13 degrees C. Parameters such as these are found very infrequently during the month of March anywhere in the Southeast United States. NWS Charleston locally extended the Tornado Watch southward over the Savannah River area toward evening. By the time the boundary pushed into far southeast Georgia by late evening, the severe weather was over.
Additional Interesting Aspects of this Event:
This event was very rare, especially considering the time of year. Early indications of the environment on this day suggest that if supercells were not closely interacting with each other and only 2 or 3 cells were able to develop with greater spacing between them, there would have been the potential for them to produce even stronger tornadoes.
Additional Storm Prediction Center Products:
Mesoscale Discussion 421 / (graphic) - issued at 221 PM EDT
Mesoscale Discussion 427 / (graphic) - issued at 741 PM EDT
Mesoscale Discussion 428 / (graphic) - issued at 949 PM EDT
Tornadoes in the Charleston CWA:
Ridgeville, SC EF1 Tornado:
Point B: 1 / 2 / 3
Point E: 1 / 2 / 3
Point G: 1 / 2
Cainhoy, SC EF1 Tornado:
Point B: 1 / 2
Point G: 1 / 2 / 3
Point I: 1 / 2
Point K: 1 / 2
"Strawberry" (near Mount Holly), SC EF1 Tornado:
Point A: 1 / 2
Point B: 1 / 2
Point C: 1 / 2
Point D: 1 / 2 / 3 / 4
Point E: 1 / 2
Allendale, SC EF2 Tornado:
Other Damage Photos: 1 / 2 / 3 - Courtesy of Linda Sanders - Allendale County Emergency Manager
Radar Image - KCLX radar storm-relative velocity image at 724 PM EDT March 15, 2008
Effingham County, GA EF2 Tornadoes:
Other Damage Photos: 1 / 2 - Courtesy of Val Ashcraft - Effingham County Emergency Manager
Radar Image - KCLX radar reflectivity and storm-relative velocity image at 943 PM EDT March 15, 2008
Surrounding WFO Event Summaries:
Local Research Paper:
Event Summary Team: Doug Berry, Robert Bright, Michael Emlaw, John Quagliariello, Steve Rowley, and Richard Thacker
Web Design: Robert Bright