This event will be mainly driven by isentropic lift over the cold front/dome that passed early morning on the 21st. Below is the forecasted 293K layer showing moist advection of parcels from the Gulf up and over pressure surfaces (more below)
And below is the forecasted SkewT from the ECMWF that shows classic winter storm sounding with just a small warm nose between 800-700mb, which means this will be primarily a sleet event over ice and snow.
This is also supported by the sref plumes
Its also not out the question we could have a brief period of thunder sleet per elevated instability
Now for those that don't quite understand isentropic ascent Ive whipped out the ol whiteboard in the form of a schematic bc thats really only way I know how to best explain it. Below is a cross section looking E or NE with DFW on left and the Gulf of Mexico on right. Warm moist air parcels from the Gulf are advected north (movement of air). Early on they reach their LCL (liquid condensation level), which means the parcel has saturated and becomes a cloud; this is in the form of stratus. The moist air parcels continue to rise up and over pressure surfaces on its journey northward until they reach their LFC (level of free convection) and they start to precipitate in the form of snow (SN). However, in our case, we have a very slight above freezing warm nose (thin red line) in which the snow falls through before reaching the boundary layer. This causes the snow to briefly melt to liquid but it very quickly reencounters subfreezing air (cold dome) where it becomes a supercooled water droplet but the depth of the subfreezing air is deep enough in the PBL that it refreezes as an ice pellet/grapeul/sleet.
Here was the end result