William’s Severe Weather Zone for Sunday:
At the surface, 11Z analysis showed a cold front over the southern Mid-Atlantic region, becoming quasistationary westward over northern KY, southern IL, northern parts of MO/KS, and northeastern CO, into a regime of lee troughing over eastern WY. By 00Z, an elongated cyclone should develop along the frontal zone from the Black Hills region to southwestern NE/northwestern KS, with the front strengthening somewhat in its KS/MO/IL segment. The boundary will move slowly northward as a warm front tonight, reaching southern IA, western IL and southern IN. To its north, elevated warm advection and moisture transport/advection will strengthen through the afternoon and especially evening. This will occur as a cyclonically curved, 55-65-kt, southerly to southwesterly LLJ shifts eastward over the region. 200-500 J/kg MUCAPE may develop, rooted between 700-800 mb, over the relatively stable frontal/boundary layer. Lift to LFC on the elevated warm-frontal slope will support potential for widely scattered thunderstorms nocturnally. Subsevere hail may occur briefly, but larger-hail potential appears too weak and conditional to warrant an outlook area. ..Edwards/Gleason.. 12/26/2021 $$