Mesoscale Discussion 0757 NWS Storm Prediction Center Norman OK 0513 PM CDT Sun May 17 2026 Areas affected...portions of central and eastern Nebraska into northern Kansas Concerning...Tornado Watch 214... Valid 172213Z - 172315Z The severe weather threat for Tornado Watch 214 continues. SUMMARY...The severe threat will continue to increase through the evening hours. 2+ inch diameter hail, 75+ mph wind gusts, and tornadoes are all possible with mature, sustained supercells. Swaths of severe wind may become the predominant concern if storm mergers occur and storms get undercut by the cold front. DISCUSSION...Supercells are maturing across central/eastern Nebraska, ahead of the merging cold front/dryline. These storms are rapidly maturing in an environment characterized by 3500+ J/kg MLCAPE and 40+ kts of effective bulk shear, which is more than adequate for intense supercells. Current live streams depict a strong tornado in progress over Howard County, NE, or roughly 15 miles north of Grand Island. Low-level shear, while currently modest will increase markedly ahead of the ongoing storms, which will support larger, curved hodographs. As such, supercells that mature and sustain themselves will have the potential to produce 2+ inch diameter hail and tornadoes, with additional strong tornadoes possible. However, the ongoing storms in Nebraska may become undercut by the cold front soon, which could also counter future strong tornado potential with those particular storms. Therefore, mesocyclonic tornado potential is strongly conditional on supercells remaining discrete ahead of the cold front. High-resolution deterministic and ensemble guidance strongly suggests that storms across eastern NE into northern KS will merge into one or more bowing segments. Should this occur, 75+ mph winds and EF0-EF2 QLCS tornadoes will become the main concerns. ..Squitieri.. 05/17/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OAX...TOP...ICT...GID... LAT...LON 38919872 40789887 41339880 41629848 41779741 41769678 41609632 41159621 40449636 39339707 38979763 38839819 38919872 MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN
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