Strong Storms Possible Saturday


The holiday weekend could start off a bit noisy thanks to an approaching storm system. A low pressure system spinning over eastern Nebraska as of late Friday evening will propagate toward the Stateline headed into Saturday. With it, it brings a chance for rain and strong to possibly severe thunderstorms.

Radar reflectivity as of 10:00PM CDT on Friday, May 22 displaying the approaching storm system

Light showers extending far east from the center of the system will likely arrive in the Stateline overnight. Scattered, light showers are expected to last through Saturday morning. By the afternoon, the rain is expected become a bit more widespread while some of the showers are forecast to intensify into scattered thunderstorms. As the storm’s triple point, the intersection of the storm’s warm, cold, and occluded fronts, moves over the Stateline, a line of strong convective storms is forecast to form and push across the area. As of Friday evening, the greatest chance for strong to severe storms looks to occur between the hours of 3:00 and 7:00 PM.

Simulated radar reflectivity and mean sea level pressure contours for Saturday, May 23 at 4:00PM CDT from the High-Resolution Rapid Refresh, or HRRR, model

The likelihood of these thunderstorms becoming severe is rather uncertain at this time. The greatest uncertainties lie with the position of the storm and its fronts and with the amount of instability that will build through the day. Though a good amount of instability is expected to be advected into the area along the storm’s warm front, limited diabatic heating caused by a likely lack of sunshine may restrict the amount of instability that builds in the lower atmosphere through the day. The coverage of these stronger storms is also expected to be very limited. Therefore, the position of the storm’s frontal boundaries in the late afternoon and early evening will be critical in determining where these storms will occur and models are not in good agreement on the storm’s path as of yet. Though ample moisture throughout the atmosphere and a good shear profile will likely promote a well-organized quasi-linear convective system if and where convection should occur.

Any and all severe weather criteria is possible including strong winds, sizeable hail, and tornadoes on top of heavy downpours, though heavy rain and strong winds are by far the biggest concern at the moment. This severe threat should not be long lived as a dry air mass closely following the storm’s center will clear out the rain and begin clearing the cloud cover by the late evening hours.

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