page_title: Tornado outbreak of May 18–21, 2013
section_title: May 19
hierarchical_section_title: Tornado outbreak of May 18–21, 2013 / Meteorological synopsis / May 19
caption_attribution_description: English: Radar image of a supercell thunderstorm to the southwest of Wichita, Kansas at 3:32 p.m. CDT (2032 UTC) on May 19, 2013 that spawned an EF2 tornado
context_page_description: The tornado outbreak of May 18–21, 2013 was a significant tornado outbreak that affected parts of the Midwestern United States and lower Great Plains. This event occurred just days after a deadly outbreak struck Texas and surrounding southern states on May 15. On May 16, a slow moving trough crossed the Rockies and traversed the western Great Plains. Initially, activity was limited to scattered severe storms; however, by May 18, the threat for organized severe thunderstorms and tornadoes greatly increased. A few tornadoes touched down that day in Kansas and Nebraska, including an EF4 near Rozel, Kansas. Maintaining its slow eastward movement, the system produced another round of severe weather nearby. Activity significantly increased on May 19, with tornadoes confirmed in Oklahoma, Kansas, Iowa, Missouri, and Illinois. In Oklahoma, two strong tornadoes, one rated EF4, caused significant damage in rural areas of the eastern Oklahoma City metropolitan area; two people lost their lives near Shawnee. The most dramatic events unfolded on May 20 as a large EF5 tornado devastated parts of Moore, Oklahoma, killing 24 people.
context_section_description: On May 19, the trough moved only slightly eastward, with many of the same areas impacted on May 18 being threatened again. During the day, two areas of low pressure developed along the trough: one over the north-central plains and the other over Oklahoma. A large plume of steep mid-level lapse rates accompanied by deep moisture (with dew points in some areas exceeding 70 °F (21 °C)) spread across much of the central and southern plains into the Mississippi River Valley. Thunderstorms in these areas were expected to develop early, though not be particularly widespread or damaging. The most intense storms were anticipated over the southern Missouri River Valley where strong daytime heating and "aggressive destabilization" would take place. Additionally, a diurnally strong jet and strong wind shear favored the development of long-lived supercells capable of producing large hail and tornadoes, some potentially violent. Activity was expected to become associated with a squall line by the evening as the cold front moved slowly eastward. In light of that, the SPC issued a moderate risk of severe thunderstorms for south-central Oklahoma, eastern Kansas, western Missouri, and extreme southeastern Nebraska.
  By the afternoon hours, rapid destabilization of the boundary layer began across eastern Kansas, prompting a tornado watch for the area. Further south in Oklahoma, a rapidly mixing dry line accompanied by a deepening surface low moved eastward into an area with deep moisture. Though leftover outflow boundaries from the previous day's storms and capping limited initial convective activity, strong daytime heating would soon allow storms to break the cap. A tornado watch was issued for the central third of Oklahoma at 2:15 p.m. CDT (1915 UTC), with the SPC noting the risk for potentially long-lived supercells and a few strong tornadoes. Around 2:30 p.m. CDT (1930 UTC), a supercell developed over Harper County, Kansas and tracked northeastward. This cell produced three short-lived tornadoes, including an EF2 to the southwest of Wichita that prompted a tornado emergency for the city. Over the course of three hours, 10 other tornadoes touched down across the state, none of which exceeded EF1 intensity.
  By 4:30 p.m. CDT (2130 UTC), the risk for significant tornadoes markedly increased over central Oklahoma, especially around the Oklahoma City metropolitan area. Maximized pressure falls ahead of the dry line allowed several storms to acquire intense updrafts and develop into rotating supercells within the state. Very strong low-level mesocyclones were expected to develop with these storms, with several tornadoes touching down. Around this time, tornadoes began touching down around the city. At 4:41 p.m. CDT (2141 UTC), a large EF3 tornado developed 3 mi (4.8 km) northwest of Luther and tracked for roughly 20 mi (32 km). To the southeast, a violent EF4 tornado formed around 6:00 p.m. CDT (2300 UTC) over Cleveland County. That storm was the strongest of the day and resulted in significant damage, especially near the city of Shawnee where two people were killed. Two other tornadoes touched down during the evening in eastern Oklahoma: one EF2 and one EF1. In addition to the two fatalities, 39 people were injured across the state.
  Storm coverage over eastern Kansas soon increased as well, with the main threat being damaging winds. Further north over parts of Iowa and Minnesota, a mid-level vortex over the region accompanied by scattered thunderstorms presented a risk of severe storms. Increasing wind shear and an influx of moist air from the south was expected to allow convection to persist over the region for much of the evening, with the main threat being damaging winds and a few tornadoes. By the evening hours, several squall lines developed across the region. Unstable air over much of Missouri allowed for these storms to maintain themselves as they moved slowly eastward. Around 7:00 p.m. CDT (0000 UTC), a rapidly moving vorticity maximum over Iowa resulted in a significant increase in thunderstorms over the area, some of which were torn
caption: Radar image of a supercell thunderstorm to the southwest of Wichita, Kansas at 3:32 p.m. CDT (2032 UTC) that spawned an EF2 tornado.
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