User:Wxtrackercody/OKC tornado

2003 Oklahoma City tornado

F4 tornado
The tornado hitting the General Motors plant
Formed	May 8, 2003, 4:10 p.m. CDT (UTC−05:00)
Duration	28 minutes
Dissipated	May 8, 2003, 4:38 pm. CDT (UTC−05:00)
Max. rating1	F4 tornado
Fatalities	134 injuries
Damage	$370 million
Areas affected	Cleveland and Oklahoma counties in Oklahoma
1Most severe tornado damage; see Fujita scale Part of the Tornado outbreak sequence of May 2003

Meteorological synopsis

May 8 marked the sixth continuous day of prolific tornado activity across the United States. That morning, the Storm Prediction Center warned for the potential of yet another significant severe weather episode as a negatively-tilted shortwave trough propagated eastward across the High Plains. Ahead of this upper-level feature, a low-pressure area was expected to form on the leeward side of the Rocky Mountains and progress from Kansas into Minnesota during the evening hours of May 8. Within the warm sector of this low, a classically unstable environment was expected to develop, with dewpoints rising above 70 °F (21 °C) and convective available potential energy (CAPE) values nearing 3,500 j/kg. Those factors, in conjunction with strong wind shear, favored an outbreak of supercell thunderstorms capable of producing very large hail, damaging winds, and strong to violent tornadoes. The SPC raised a high risk of severe weather across portions of Kansas, Missouri, and Nebraska early on May 8 accordingly. Farther south across central and southern Oklahoma, wind fields were originally expected to be weaker and slightly less conducive to strong tornadic activity, and so a slight risk was issued there. As the day evolved, however, forecasters gained confidence that an outbreak of severe weather would likely extend southward along the dry line; Oklahoma was subsequently added to the high risk area that afternoon.

Central and southern Oklahoma had already been impacted by tornadoes during the pre-dawn hours of May 8. Later that day, much of the state was engulfed by a capping inversion that prevented the formation of additional convection. Around 1 p.m. CDT, a special weather balloon release indicated that this cap was rapidly weakening, which was further evidenced by the development of cumulus clouds along the dry line stretching from southwestern Oklahoma into south-central Kansas. Here, CAPE had increased in excess of 4,500 j/kg, At 2:30 p.m. CDT, the National Weather Service forecast office in Norman, Oklahoma, issued their first ever live severe weather briefing across its NOAA Weather Radio stations as storms first began to develop on radar. These cells initially struggled to tap into the unstable and sheared environment, which is typical at the onset of a significant severe weather event. However, one storm began to intensify after 4 p.m. CDT, prompting the first severe thunderstorm warning nine minutes later. At 4:33 p.m. CDT, the Norman office issued their first tornado warning for Grady County; at 4:49 p.m. CDT, this warning extended into Cleveland, McClain, and southern Oklahoma counties.

Tornado track

At 5:10 p.m CST, a tornado began in Cleveland County near the intersection of Northwest 5th Street and Santa Fe Avenue in Moore. The tornado progressed eastward, quickly inflicting F3 damage to structures while growing to a maximum width of 0.25 mi (0.40 km). Given the large and potentially violent tornado ongoing, the Norman office issued a tornado emergency at 5:19 p.m. CDT. The most severe damage in Moore was observed as the tornado approached Interstate 35, where multiple structures were completely leveled and cars were tossed distances of 100 yd (91 m) or more. On Interstate 35, it intersected a southward-moving Greyhound bus carrying 23 passengers. Some individuals chose to take shelter in a nearby ditch while others sought refuge on the bus. Of those that remained in the vehicle, eight were injured trapped between buckled walls and seats, hung upside down, or thrown out broken windows. Eleven people in the ditch sustained injury from flying debris. The tornado continued through southeastern portions of the Highland Park residential area, just two blocks south of areas impacted by the 1999 Bridge Creek–Moore F5 tornado. A north-northeast curve brought the tornado across Northeast 27th Street and Eastern Street into the Lakeside Golf Course. Approximately 1 mi (1.6 km) from this path, it overlapped with the Bridge Creek–Moore tornado. More than a dozen residences in a subdivision just south of 89th Street and west of Bryant Avenue were heavily damaged or destroyed. In fact, several homes impacted in the northwestern part of this subdivision had been demolished in the 1999 tornado and were less than 4 years old.

The tornado crossed Southwest 89th Street into Oklahoma County, where it reached a maximum width of 0.4 mi (0.64 km). It continued across Air Depot Boulevard, where the tornado impacted the General Motors Corporation Assembly Plant at F4 intensity. A newly-built paint shop was most severely damaged, and new production parts and equipment inside the structure were exposed to the outside. The body shop, power house, and a few cooling tanks suffered a significant impact too. The stack of one of the boilers was sheared off, more than 600 newly assembled sport utility vehicles parked outside were damaged or destroyed, and approximately 100 employee vehicles were damaged. One compact car in particular was flipped vertically and wedged into the side of the paint shop. While 2 truck drivers making deliveries to the plant sustained minor injuries, a majority of the more than 1,000 plant employees remained unscathed by moving to adequate shelter in advance of the tornado.

It then moved into the southeastern sections of the Tinker Air Force Base, where an ammunition storage bunker and a guard shack near the intersection of Southeast 59th Street and Douglas Boulevard were heavily damaged. Southeast of this location, a number of homes were destroyed in the northern part of the Kennington neighborhood, including two that were completely demolished in accordance with F4 damage. The tornado continued across Interstate 40 and into a residential area west of Westminster Road, where it exhibited signs of a multi-vortex structure. In a residential area of Choctaw, three homes were demolished, including damage to one house that was warranted an F4 rating. The tornado narrowed in size and intensity before ultimately dissipating southwest of Indian Meridian Road and Reno Avenue at 5:38 p.m. CDT. In total, it was on the ground for 17.3 miles and 28 minutes, reaching a peak width of nearly 0.4 miles (770 yd). No fatalities occurred but 134 people were treated for injuries, 45 in Cleveland County and 89 in Oklahoma County. Total losses amounted to $370 million.