Shortwave Trough Fires Supercells for Giant Hail in Western SD, North Nebraska — SevereWX

Storms are bubbling up along a stationary boundary near Chadron, Nebraska, and in central South Dakota, fueled by a weak shortwave trough sliding into eastern Wyoming. SPC's Mesoscale Discussion 1534 highlights how surface heating is eroding low-level inhibition (MLCIN), paving the way for more widespread development by late afternoon into early evening.

With the low-level jet ramping up tonight, expect supercell structures amid 40-45 kt effective shear and steep mid-level lapse rates (8.3 C/km near UNR, steeping lower). Large hail up to 2.5 inches is the headliner threat, alongside damaging winds potentially reaching 55-70 mph. Some storms could upscale into clusters moving east along the boundary, boosting the wind risk further.

Watch issuance odds sit at 80% through 2200Z, covering portions of western/central South Dakota and far northern Nebraska. Peak threats include 1.50-2.5 inch hail, 55-70 mph gusts, and low-end tornadoes up to 90 mph.

Timing looks primed for 3-6 PM CDT initiation, intensifying into evening. Keep an eye on radar trends—stay prepared with helmets for hail protection, secure outdoor items, and have multiple alert sources ready.

Monitor SPC for watch updates and local NWS offices (FSD, ABR, LBF, UNR, CYS). Safety first: know your safe room and act on warnings.