Storm Events Database
|Begin Date||05/11/2011 14:00:00 CST-6|
|Begin Location||ST PAUL|
|End Date||05/11/2011 14:00:00 CST-6|
|Deaths Direct/Indirect||0/0 (fatality details below, when available...)|
|Episode Narrative||After a rather quiet start to the severe weather season in South Central Nebraska, things changed in a hurry during the early to mid afternoon hours on this Wednesday as a line of severe thunderstorms marched from southwest to northeast across much of the area, but primarily impacting counties along and east of Highway 281. Although widespread straight line wind damage was the main story, there were also three confirmed tornadoes embedded within the line, consisting of an EF0 in extreme southern Adams County, an EF1 several miles north of Hampton in Hamilton County, and another EF1 that actually touched down on the edge of Osceola in Polk County. These tornadoes were relatively short-track, but did cause some damage. In terms of straight line wind damage, one of the many reports included 22 vehicles with rear or side windows blown out by flying gravel at Sandy Creek School south of Clay Center. There were only a handful of hail reports, none of which were larger than nickels. No injuries were reported from these storms.
The primary driving force for severe weather was a powerful, negatively tilted mid and upper level low pressure system centered over Colorado. At the surface, a fairly well-defined quasi-stationary front extended across the region from southeast Colorado to east-central Nebraska, with a few areas of low pressure along it. This surface front marked a sharp division in instability, with mid-day mixed-layer CAPE values ranging from negligible across western portions of South Central Nebraska, to between 1500-2500 J/kg in eastern counties. Deep layer vertical wind shear on the order of 30-50 knots was also present, making the environment conducive to fairly widespread severe storm development.
Focusing on storm mode and timing, the nearly solid line of severe storms lifted northeast across South Central Nebraska in a generally west-northwest to east-southeast orientation, first crossing into the state out of north central Kansas around 1 PM CDT, and eventually exiting the Polk and Nance County areas around 4 PM CDT. While strong to severe wind gusts of 50-70 MPH were common across several counties, the brief tornadoes were likely a result of the line of storms encountering enhanced low level shear and easterly low-level winds along and north of the quasi-stationary front.
|Event Narrative||Wind gusts were estimated at 60 mph.|
All events for this episode:
|DESHLER||THAYER CO.||NE||05/11/2011||12:35||CST-6||Hail||0.75 in.||0||0||0.00K||0.00K|
|HEBRON||THAYER CO.||NE||05/11/2011||12:43||CST-6||Hail||0.88 in.||0||0||0.00K||0.00K|
|CARLETON||THAYER CO.||NE||05/11/2011||12:58||CST-6||Hail||0.75 in.||0||0||0.00K||0.00K|
|FAIRFIELD||CLAY CO.||NE||05/11/2011||13:00||CST-6||Thunderstorm Wind||52 kts. EG||0||0||30.00K||0.00K|
|HENDERSON||YORK CO.||NE||05/11/2011||13:32||CST-6||Thunderstorm Wind||52 kts. EG||0||0||0.00K||0.00K|
|ST PAUL||HOWARD CO.||NE||05/11/2011||14:00||CST-6||Thunderstorm Wind||52 kts. EG||0||0||0.00K||0.00K|
|SWEDEHOME||POLK CO.||NE||05/11/2011||14:02||CST-6||Thunderstorm Wind||61 kts. EG||0||0||35.00K||0.00K|
|OSCEOLA||POLK CO.||NE||05/11/2011||14:03||CST-6||Thunderstorm Wind||55 kts. MG||0||0||0.00K||0.00K|
|STROMSBURG||POLK CO.||NE||05/11/2011||14:15||CST-6||Thunderstorm Wind||52 kts. EG||0||0||0.00K||0.00K|
|GENOA||NANCE CO.||NE||05/11/2011||14:32||CST-6||Thunderstorm Wind||61 kts. EG||0||0||0.00K||0.00K|