National Weather Service United States Department of Commerce

At 6:00 PM CST on March 12th (0000 UTC 13 March), a strong ridge of high pressure was present across the southeastern United States, while an upper-level closed low and associated trough covered the western half of the country. The central plains were located in a rather tight pressure gradient between the approaching trough to the west and ridge to the east. The 850 mb plot showed low-level Gulf moisture streaming northward on a 35-knot low-level jet from southern Texas to Iowa. Southwesterly flow aloft and vorticity advection over the Rocky Mountains, as seen on the 500 mb analysis, provided favorable conditions for low-level lee cyclogenesis. Thermal ridging from western Texas northward into western Kansas at 850 mb was an indication of the developing cyclone. Surface analysis showed a pronounced dryline extending from western Kansas into western Texas, and a 1004 mb low in eastern Colorado. A stationary front was located along the Kansas-Nebraska border and a cold front was analyzed from southern Minnesota southwestward to central New Mexico. By 9:00 PM CST (0300 UTC), the primary area of surface moisture convergence was across south-central Oklahoma, and this area expanded northward by 12:00 AM CST (0600 UTC). The moisture axis extended from central Texas northward to central Kansas.

At 6:00 AM CST on March 13th (1200 UTC), temperatures were warming into the mid 60s just ahead of the dryline, in western Oklahoma and Kansas, as seen on the surface analysis. The first tornado watches of the day were issued from west-central Kansas southward into western Oklahoma. The low-level pressure gradient tightened across the central plains and wind speeds increased, as evident on the 925 mb analysis. The 1200 UTC soundings showed veering wind profiles and substantial speed shear across the entire region. A 50-knot low-level jet at 850 mb was present on the Amarillo, Topeka, and Dodge City soundings. The 250 mb and 300 mb analyses showed an upper-level difluence zone across southern Oklahoma and northern Texas. A cyclone with a central pressure of 1000mb moving into western Kansas and the Oklahoma panhandle was analyzed on the 9:00 AM CST (1500 UTC) surface analysis. The dryline remained clearly defined across western Kansas and Texas.

At 12:00 PM CST (1800 UTC), the surface cyclone had a central pressure of 998 mb and had deepened to 996 mb by 3:00 PM CST (2100 UTC). The increasing pressure gradient across western Kansas and Oklahoma amplified surface convergence near the low and along the dryline. Daytime turbulent mixing became sufficient to push the dryline into western Oklahoma by 3:00 PM CST, as temperatures rose into the low to mid 70s across western and central Oklahoma. A warm front was also evident from Minnesota southwestward into northwestern Kansas on the mid-afternoon surface analysis. The first tornadic supercells developed over west-central Oklahoma, as the dryline began to progress across the state. At 4:44 PM CST, the tornado outbreak was initiated by an F2 twister touching down in Grady County.

The 6:00 PM CST (0000 UTC 14 March) upper-air analysis showed a closed low across Utah, Wyoming, and Colorado. Cold mid-level temperatures were associated with the low, as seen in the 500 mb analysis, and were being advected into the western Kansas, Oklahoma, and Texas by strong, southwesterly winds from 700 mb to 500mb. This upper-level cooling steepened lapse rates seen on the Amarillo and Dodge City 0000 UTC soundings and further destabilized the atmosphere. The upper-level trough had progressed into the central plains, strengthening speed shear across the region. Both the 925 mb and 850 mb analyses showed ample moisture streaming northward from the Gulf of Mexico into Texas, Oklahoma, and Kansas. The 925 mb winds at 0000 UTC across Texas and Oklahoma backed to southeasterly, allowing for enhanced low-level convergence along the dryline. Surface analysis showed the cyclone had moved northeasterly to the central Kansas-Nebraska border. By about 6:00 PM CST, 7 tornadoes had been reported across the state of Oklahoma.

At 9:00 PM CST (0300 UTC), the original area of surface low pressure had moved into eastern Nebraska, while a secondary cyclone formed across southwestern Texas. A cold front extended across the plains, between the two surface cyclones. By 12:00 AM CST on March 14th (0600 UTC), tornado watches covered eastern Kansas, nearly the entire body of Oklahoma, and parts of north Texas. Thunderstorms lined up from the Nebraska-Iowa border southward into central Texas. The 3:00 AM CST (0900 UTC) surface analysis showed a series of mesohighs and mesolows along the cold front across Kansas, central Oklahoma, and Texas. Reports of severe hail and strong thunderstorm winds continued until dawn across southern and eastern Oklahoma.