A very small area of severe winds resulted from nearby thunderstorms during the very early morning hours on this Sunday. Throughout the nighttime hours, a small mesoscale convective system, comprised primarily of multicell thunderstorms, propagated east along and just south of the Nebraska-Kansas state line. Northward moving outflow resulted in a little tree damage in the town of Axtell. Nearby observations at Holdrege and Hastings suggested these winds were associated with a heat burst. At 4 a.m. CST, the temperature at Hastings rocketed to 89 degrees, and the dewpoint plunged to 48. The previous hour both values were 76 and 64, respectively. That 89 degrees was the high temperature for the date. Winds at Holdrege gusted to 45 mph. The temperature and dewpoint changes there were not quite as impressive.
These thunderstorms formed in the warm sector, south of a wavy front that extended from New England, through the Ohio Valley, then northwest to low pressure over South Dakota. The rest of the front trailed southwest to Nevada. Convective initiation was most likely associated with the low-level jet, which had increased to 55 kts by daybreak. In the upper levels, forcing was negligible. Zonal flow was over the northern half of the United States, with weak anticyclonic flow over the southern U.S. A closed high was over New Mexico. Prior to the outflow moving through, temperatures were in the middle 70s, with dewpoints in the middle 60s. Mid-level lapse rates were steep, at least 8.5 degrees C/km. This resulted in MLCAPE of 1500 to 1900 J/kg. The nearest sounding, at North Platte, a few hours later (1200 UTC or 6 am CST), indicated a loaded gun profile, except winds were weak below 500 mb.