ACUS11 KWNS 190311 SWOMCD SPC MCD 190310 OKZ000-190445- Mesoscale Discussion 0781 NWS Storm Prediction Center Norman OK 1010 PM CDT Mon May 18 2026 Areas affected...portions of northern Oklahoma Concerning...Severe potential...Watch possible Valid 190310Z - 190445Z Probability of Watch Issuance...60 percent SUMMARY...The severe threat may increase over northern OK over the next few hours as storms back-build southwestward along a southward drifting cold front. Severe gusts are the main threat, though an instance or two of hail or a tornado are possible. Convective trends are being monitored for the need of a WW issuance. DISCUSSION...Robust multicellular convection, with a history of measured severe gusts, has been steadily back-building west-southwestward along and immediately behind a southward sagging cold front. Despite weak upper support, strong low-level convergence has been supporting persistent convective development, especially given a 50 kt southerly low-level jet bisecting the cold front nearly perpendicularly. Ahead of the front, upper 60s F surface dewpoints beneath 8-9 C/km mid-level lapse rates are yielding 3000+ J/kg MLCAPE per the 00Z OUN/LMN soundings and 02Z mesoanalysis. These same data sources also depict sizeable low-level hodographs with 300 m2/s2 effective SRH and 40+ kts of effective bulk shear. As such, the ambient environment clearly supports severe potential. The primary uncertainty is how far southwest convection will initiate along the southward-sagging front, and the timing for storms to propagate into OK. The current thinking is that storms capable of severe gusts will eventually propagate southward into north-central and northeast OK. An instance or two of severe hail could accompany the stronger storm cores, and a tornado cannot be ruled out if a robust updraft can outpace the cold front. Convective trends will continue to be monitored for convective propagation into OK. ..Squitieri/Mosier.. 05/19/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TSA...OUN... LAT...LON 36779919 36929821 36999709 36969623 36739582 36449572 36099589 35879664 35809745 35909809 36089856 36429904 36779919 MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN