Summary
A very complex scenario is set to unfold across the Southern Plains into the Upper Mississippi Valley. During the late morning hours a low pressure system will be orientated across South Dakota.
Dew points will begin to rise into lower 60s as a southernly flow increases further east prior to a negatively tilted trough. Convection prior to Thursday evening will be ongoing from Nebraska into Iowa.
Convection is also expected even further south across Kansas and Missouri. This convection is expected to be in a weakening state as it will only be supported by low 50’s dewpoints. By late morning early/afternoon all convection should have dissipated due to very low moisture. This will allow atmosphere recovery to occur.
Overall, severe thunderstorms are expected into the early evening and nighttime hours.
Kansas, Nebraska, Northern Missouri, and Southwestern Iowa
Weakening convection will be ongoing during the morning hours as most CAM solutions show scattered to numerous thunderstorms. Dewpoints are expected to be very dry early morning as convection moves through. No severe threat is expected in the morning.
However, by late morning dry air will create a perfect opportunity for atmosphere recovery. During this time, a cold front will be positioned across Eastern NE/KS. Dewpoints will soar into the mid 60s and most CAM solutions have ML CAPE around 2500 J/kg and SB of around 3000 J/kg this with SFC-1km shear of 45kts will be sufficient for the development of supercells posing the risk of all hazards.
Storms will quickly fire along the dryline and race eastward growing upscale. Given the strength of the directional shear and elongated hodographs on forecast soundings. The atmosphere will be supportive of rotating (potentially cyclic) storms. A strong tornado cannot be ruled out either. Storms will also be supportive of large hail (possibly +2″) and damaging winds.
Oklahoma and Texas
Strong instability combined with low 70s dewpoints will create a unstable airmass across much of Eastern Oklahoma into the Red River Valley. Forecast soundings indicate a weak capping inversion will be present across the region, however lift should be sufficient enough for storms to form.
Shear will be the main focus on if storms can organize. Weak shear is expected to inhibit and potentially disorganize most of the storms that do fire. Nevertheless, isolated to scattered storms are expected by late afternoon. Storms will be capable of large to very large hail, isolated tornadoes, and damaging wind gusts.
Storms may grow upscale into a cluster however this is still very uncertain. Trends will be monitored with the timing and location of storms.