Nebraska-Kansas Chase (June 27)

Severe t-storm reports in the past for similar setups.

The severe thunderstorm threat today targets southwest/south-central Nebraska down into the northwestern chunk of Kansas. A few isolated tornadoes will be possible, especially just northeast of a surface low from mid to late afternoon. The low is nearly stationary in far western Kansas this morning. Along a quasi-stationary front, winds are backed around toward the east and this highlights the amount of low-level shear in the atmosphere.

On top of this directional shear, relatively strong flow aloft, approaching shortwave energy and an increasingly unstable air-mass will combine to create an environment supportive of supercell thunderstorms. Very large hail may be the biggest threat here, with tornadoes being secondary. Into the evening, the storms should merge and they may cause a more widespread damaging wind threat. With all this said, this is not the ideal tornado setup. Winds are also backed around 500mb, so hodographs aren’t showing the large, looping patterns typically associated with big tornado days.

It will come down to short-term trends around midday and early afternoon to pick out the best chase spot. Right now, the general target is the western border between Nebraska and Kansas. South into western Kansas, dew-points are in the mid to upper 60s. To the north in southwestern Nebraska, winds are backed around to the east. It’s where these two areas meet that has the greatest tornado potential.

Here’s a look at the 13z HRRR STP forecast: