A deadly tornado outbreak occurred in Central Texas during the afternoon and evening of May 27, 1997, in conjunction with a southwestward-moving cluster of supercell thunderstorms.

Instead, the coalescence of several weather features—including a cold front, a dry line, and a gravity wave—provided locally favorable conditions for rotating thunderstorms and the formation of tornadoes.

The severity of the 1997 Central Texas tornado outbreak was predicated on an unusual spatial and temporal alignment of weather features at highly localized scales.

[4] Instead, the most prominent weather system over the central U.S. at the time was a distant upper-level low centered over Nebraska imparting little influence on atmospheric conditions over Texas.

[5] Further aloft at the level of the jet stream, there were two nearby wind speed maxima over northern Mexico and the central Mississippi Valley; this led to strong divergence of air over Texas.

The combination of several days of onshore wind flow from the Gulf of Mexico and the persistence of a capping inversion aloft led to an accumulation of moist air over the state.

[11] A study published in Monthly Weather Review in 2007 described the environment as being "marginally favorable for supercells and unfavorable for significant, supercellular tornadoes.

On the preceding evening, a mesoscale convective system developing along this dry line over eastern Oklahoma and Arkansas generated a well-defined gravity wave that traveled southwest across East Texas on the morning of May 27.

A swath of clear skies emerged between the two boundaries, maximizing surface heating during the daytime and contributing to the weak low-pressure area's southwestward movement through Central Texas.

[17] Thunderstorms formed near Waco in tandem with this juxtaposition of features and within a local maximum of surface heating and convergence of moist air.

[3] While some storms had spawned along the cold front, the gravity wave's passage in the early afternoon hours coincided with a rapid intensification of the first thunderstorms.

[18] The development of new discrete supercells followed the advancing intersection of the cold front and dry line and the gravity wave as they continued southwest,[3][19] though each individual storm was nearly stationary.

[3] The direction of the storms' expansion towards the southwest deviated over 100 degrees away from these westerly winds, representing an extreme and highly unusual motion.

[4] The final tornado of the day touched down in Frio County and lifted at 7:23 p.m.[14]: 2 [1]: 214 Farther south away from the southwestward-moving storm cluster, the cold front and dry line curved west, making them parallel to the advancing gravity wave; this triggered the development of numerous and intense storms between Austin and the Big Bend after 3:00 p.m. when the gravity wave intersected the front.

The SPC predicted that the gravity wave would be a focal point for storms capable of producing large hail and damaging winds given the unstable atmosphere.

A subsequent outlook issued by the SPC at 10:16 a.m. continued to indicate a moderate risk for severe weather and mentioned the possibility of isolated and brief tornadoes.

[31][32] A tornado watch was later issued by the SPC at 12:54 p.m. for parts of eastern Texas and western Louisiana, citing the unstable airmass in place over the region.

[33] Interviews conducted by a National Oceanic and Atmospheric Administration service assessment team found that many watched the approach of tornadoes prior to taking shelter due to their slow movement and high visibility.

[39]: C3  An aerial survey conducted by the Birmingham, Alabama, office of the National Weather Service included the damage caused by the earlier F2 tornadoes—mostly to trees and roads—as part of the overall Jarrell tornado path.

[74] Tracking south-southwest,[28] the tornado quickly intensified and grew to a 1⁄2 mile (0.80 km) in width, changing from its initial thin and white appearance to a blue and black color.

[14]: 6  Much of the neighborhood was completely swept away with little debris remaining, with what was left being reduced to small and unrecognizable fragments that were dispersed over a wide area.

[82] Trees in the neighborhood were completely denuded and stripped entirely clean of all bark as well, including one that was found with an electrical cord impaled through the trunk.

[92][93] Shortly after entering this forested area, the path of damage left behind by the tornado ended abruptly, with the National Centers for Environmental Information indicating that it lifted at 3:53 p.m. after remaining on the ground for 13 minutes and 5.1 miles (8.2 km).

[g][96] The critique noted that some of the homes at Double Creek Estates, although built within the preceding 15 years, exhibited structural weaknesses in their design such as the lack of anchor bolts and steel straps in their foundations.

[28] In addition to the tornadoes, there were 12 reports of large hail in Central Texas received by the National Weather Service during the late afternoon and evening.

[66]: A21  A temporary shelter was established by the American Red Cross at Jarrell High School for those displaced by the tornado,[67]: A10  providing food and accepting clothes donations.

[99] The Jarrell Volunteer Fire Department organized a temporary morgue;[67]: A10  the deceased were later brought to the Travis County Forensic Center for identification.

[86] Although a death toll of 30 people was initially reported, that figure was later revised to 27; the inflated count was attributed to the dispersion of remains that led some fatalities to be tallied twice.

[106] Vouchers were distributed by the American Red Cross to storm victims in the Buttercup Creek subdivision for clothing, food, and other supplies.

[107][108] The events and survivor accounts of the tornado were profiled in television documentaries such as the 1999 episode of HBO's America Undercover series titled "Fatal Twisters: A Season of Fury",[109][110] the 1999 BBC television series titled Twister Week (also known as Tornado Diary in the United States) in an episode titled "Tornado Alley",[111] the seventh episode of the Discovery Channel program Storm Warning, produced by GRB Entertainment,[112] and the 2006 documentary Ultimate Disaster (also known as Mega Disaster) on National Geographic Channel.