ZCZC SPCSWOMCD ALL ACUS11 KWNS 280034 SPC MCD 280034 KSZ000-NEZ000-280130- Mesoscale Discussion 0839 NWS Storm Prediction Center Norman OK 0734 PM CDT Mon May 27 2019 Areas affected...Portions of central into northern Kansas...south-central Nebraska Concerning...Severe potential...Watch likely Valid 280034Z - 280130Z Probability of Watch Issuance...80 percent SUMMARY...The threat for severe may be increasing across portions of central Kansas into south-central Nebraska. Initial discrete modes are expected, with large hail, damaging winds, and isolated tornadoes possible. Later in the evening, storms approaching from the west (in Severe Thunderstorm Watch 0265) may also pose a severe threat. The issuance of a WW is likely. DISCUSSION...Convective initiation has been noted along the Trego/Ellis County Kansas line within the last few minutes. Some deep-layer ascent appears to be glancing the area, with a small mid-level perturbation ejecting into the central Plains from Colorado, overspreading the dryline, where some low-level convergence is present. The ambient environment may be characterized by moderate to strong instability (with up to 3000 J/kg MLCAPE noted in northern Kansas), and strong deep-layer shear (effective bulk shear of 50-70 knots). Any storm that can mature and sustain itself in this environment may become supercellular. Given the recent increase of effective SRH to 200-300 m2/s2 associated with a strengthening low level jet (with enlarged, curved hodographs depicted by RAP forecast soundings), storms may also acquire strong low-level rotation, especially if a discrete mode is maintained. Such storms will have the highest potential for producing isolated tornadoes. Otherwise, storms will be capable of producing damaging wind gusts and large hail as they spread into central Nebraska. Sparse instances of very large hail also cannot be ruled out given the high amounts of available buoyancy in the -10 to -30C layer. Latest high resolution model data depicts an increase in storm coverage later this evening, especially in Nebraska, as high theta-e air is advected over a baroclinic zone. ..Squitieri/Hart.. 05/28/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OAX...TOP...ICT...GID...DDC...GLD... LAT...LON 38300061 39460001 40699956 41199882 40939759 40319679 39389684 38449894 38300061 NNNN