Hail in Texas, October 21, 1996

A warm, moist and very unstable air mass had established itself over northern Texas on the 20th and 21st. A strong capping inversion over the area inhibited thunderstorm development on the 20th but the cap was weakened early on the 21st as an upper level trough shifted into the Southern Plains. Thunderstorms developed along a Pacific cold front in the western portions shortly before sunrise, then moved ahead of the boundary into the highly unstable air mass. Low level wind shear was conducive for some of the storms to become supercell thunderstorms and one such storm moved across Hood, Johnson, southern Tarrant, Dallas, and Rockwall Counties between 0600 CST and 1000 CST. Extensive damage from downbursts and tornadoes, and hail up to golfball size occurred with this storm. Another supercell developed on the front over Stephens County during the mid-morning hours. This storm moved across Palo Pinto, Parker, Tarrant, Dallas, Rockwall, Kaufman and Van Zandt Counties with hail up to baseball size and damaging microbursts. Other severe thunderstorms redeveloped along the front as it moved into the central portions of the area around midday. One of these storms became a supercell over western Tarrant County and hail to softball size and damaging downbursts occurred as it tracked across Tarrant, southeast Denton and Collin Counties. By early afternoon, an outflow boundary from the morning's thunderstorm activity had pushed into the southern portion of North Texas and extended near a Waxahachie to Comanche line. Two tornadic supercells developed and tracked east-northeast along the boundary across Comanche, Hamilton, Bosque, Hill and Ellis Counties. Hail to baseball size and at least four brief tornadoes were produced by these storms.By early evening, the Pacific front had pushed into east Texas, ending much of the thunderstorm activity over north central Texas. This activity, however, redeveloped over the area later in the evening as an arctic front and a strong upper level disturbance approached. A few of the storms that formed above the shallow arctic air mass briefly became severe producing nickel to quarter size hail.