page_title: 2011 Philadelphia, Mississippi tornado
section_title: Meteorological synopsis
hierarchical_section_title: 2011 Philadelphia, Mississippi tornado / Meteorological synopsis
caption_attribution_description: English: Damage swath of the 2011 Philadelphia, Mississippi, tornado based on the Enhanced Fujita scale
context_page_description: During the afternoon of Wednesday, April 27, 2011, a violent EF5 tornado touched down in eastern Mississippi, killing three people. Part of the historic 2011 Super Outbreak, the largest tornado outbreak on record, this was the first of four EF5 tornadoes to touch down that day and the first such storm in Mississippi since the 1966 Candlestick Park tornado. While on the ground for 30 minutes, it traveled along a near 29-mile path through four counties, leaving behind three deaths, eight injuries, and $1.1 million in damage.
  The supercell thunderstorm that produced this tornado formed around 1:00 p.m. CDT south of Jackson, Mississippi. Traveling briskly to the northeast, it became severe within 25 minutes and potentially tornadic by 1:36 p.m. CDT. A tornado finally touched down at 2:30 p.m. CDT just east of the Philadelphia Municipal Airport. It quickly intensified and began producing EF5 damage by 2:38 p.m. CDT; extreme ground scouring, up to 2 feet deep in places, occurred in northeastern Neshoba County. After crossing into Kemper County, the tornado obliterated a mobile home, killing all three inside.
context_section_description: The environmental conditions leading up to the April 2011 Super Outbreak were among the "most conducive to violent tornadoes ever documented". On April 25, a vigorous upper-level shortwave trough moved into the Southern Plains states. Ample instability, low-level moisture, and wind shear fueled a significant tornado outbreak from Texas to Tennessee; at least 64 tornadoes touched down that same day. An area of low pressure consolidated over Texas on April 26 and traveled east while the aforementioned shortwave trough traversed the Mississippi River and Ohio River valleys. Another 50 tornadoes touched down on that day. The multi-day outbreak culminated on April 27 with the most violent recorded day of tornadic activity since the 1974 Super Outbreak. Multiple episodes of tornadic activity ensued with two waves of mesoscale convective systems in the morning hours, followed by a widespread outbreak of supercells from Mississippi to North Carolina during the afternoon into the evening.
  Activity on April 27 was precipitated by a 995 mbar (hPa; 29.39 inHg) surface low situated over Kentucky and a deep, negatively tilted (aligned northwest to southeast) trough over Arkansas and Louisiana. A strong southwesterly surface jet intersected these systems at a 60° angle, an ageostrophic flow that led to storm-relative helicity values in excess of 500 m²s⁻²—indicative of extreme wind shear and a very high potential for rotating updrafts within supercells. Ample moisture from the Gulf of Mexico was brought north across the Deep South, leading to daytime high temperatures of 77 to 81 °F (25 to 27 °C) and dewpoints of 66 to 72 °F (19 to 22 °C). Furthermore, convective available potential energy (CAPE) values reached 2,500–3,000 J/kg⁻¹.
caption: Damage swath of the tornado across eastern Mississippi
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