Area of focus will be KS/OK, where dryline convection is forecast by all high-res models. There are timing differences between SPC WRF, HRRR, and OUN WRF…with OUN WRF and HRRR convecting earlier. Late morning OA indicating that cap has weakened to under 25 j/kg along and east of dryline so initiation before 20z possible near and south of Red River. Later initiation expected farther north across west-central and northwest OK, and with diurnal backing and low-level jet intensifcation, early this evening, intensification and tornado potential will increase by 23/00z.
Primary area of concern will be northwest Oklahoma into south-central Kansas (OUN-ICT CWAs) where tornadic potential will be higher and overall coverage expected to be greater. Although instability will be substantial farther south, better shear/LCL values will be seen farther north across nw OK into srn KS. This idea, with much greater updraft helicity forecasts, is supported by OUN WRF. Any convection in SW OK/NW TX is fcst to occur fairly early with weak cap…but not develop particularly strong or rotating updrafts. Concern that if a large area fires too early that may limit additional convectiv e development over nw OK or s-central KS due to cirrus debris. Still…low-level jet strengthening by evening may be enough to help support stronger convection in KS.
18Z position of dryline is just east of DDC to GAG/CDS/SNK. Little in the way of eastward mixing is expected today given deeper moisture to its east and strong jet/ht falls to its west. If storms can get going over west-central and northwest Oklahoma, they should have a better chance of survival off/east of dryline with much better flow over that region.
Despite some degree of uncertainty in timing and exact locations for supercell development in the srn Plains today…high res model guidance and lack of jet cirrus are giving us more confidence that deep convection will in fact develop in a few spots along dryline compared to yesterday…and thus it makes sense to stay focused on the OUN/DDC/ICT CWAs throughout the day…rather than spending any time at all evaluating products in the mid-Atlantic, where shallow convection under persistent upper low is expected to fire again with diurnal heating. In fact some very shallow convection already occuring and overall severe threat looks very minimal there.