A new animation of imagery from NOAA's GOES-East satellite shows several outbreaks of severe weather from May 15-21, 2013, over the south central United States. Over the course of seven days many tornadoes touched down including two powerful EF-4 tornadoes and one EF-5 tornado. All of the weather systems that spawned these outbreaks are seen in the new animation.
Day after day, warm, moist winds from the Gulf of Mexico brought a river of low-level and unstable air into the Midwest. The latent energy it carried exploded in the heat of each day into violent thunderstorms. The storms mostly occur along a rise in altitude that triggers convection (rising air that form thunderstorms).
The tornado outbreak from May 15-17, 2013, produced several damaging tornadoes in northern Texas, south-central Oklahoma, northern Alabama and northern Louisiana. The outbreak produced 23 tornadoes.
Three tornadoes moved through a stretch of Texas near the Dallas-Fort Worth area on May 15. One of those tornadoes swept through the town of Granbury. According to the National Weather Service, the Granbury tornado was an EF-4, based on the Fujita tornado damage scale. Winds in an EF-4 tornado are between 166 and 200 mph. On May 16, more tornadoes touched down and moved through Hood County, Texas and hit the towns of Cleburne and Ennis. The tornado that touched down in Cleburne was an EF-3, according to the NWS. An EF-3 tornado has winds between 136 and 165 mph.
The tornado outbreak from May 18-21 impacted the Midwest and lower Great Plains, generating several tornadoes. On May 18, amidst several tornadoes in Nebraska and Kansas, an EF-4 tornado touched down near Rozel, Kansas. May 19 brought the generation of tornadoes in Kansas, Iowa, Missouri, Illinois and Oklahoma. On May 20 the large EF-5 tornado touched down in Moore, Oklahoma.
All of these storm systems are seen during the span of this GOES-13 satellite data animation. The animation was created by the NASA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md.