On July 28, 2014, atmospheric conditions sufficient to produce a number of strong supercells, and several weak tornadoes again threatened the Colorado Front Range. A tornado touched down near Ft. Lupton, in Weld County, and near Denver International Airport (DIA), in Adams County. Gene Acker reported seeing two tornadoes, the first he filmed (See slideshow.), and the other tornado was too close, so he acted to avoid the storm. Gene indicated seeing debris at ground level in both tornadoes. The first tornado was a land spout tornado with a good sized funnel cloud overhead and debris cloud on the ground. The second tornado was wider and more rain wrapped.
Atmospheric conditions present, before these Front Range supercell tornadoes formed were: 60+ dew points, 89f degree surface temperatures, a cold jet flow aloft from the west to east at 300mb, 10-15mph surface winds backed from the southeast, 2,000+ CAPE, presence of a noticeable jet streak aloft with gravity waves below, just before these supercells formed. Cumulus cloud (cu) towers started building in the late afternoon several hours before the tornadoes. These cloud towers were ingested into several parent altocumulus storms, and two of these storms formed into persistent supercell structures.
One of these 'tornado warned' storms was present over DIA. As the storm progressed toward DIA, air travel passengers were warned and then sent to tornado shelters, and flights were temporarily delayed. The strong storms produced large amounts of pea and dime sized hail, some lightning (mostly cloud-to-cloud), and also produced several weak tornadoes.
Tomorrow, more somewhat stationary thunderstorms are expected to release large amounts of rain, and are likely to pose flash flood risks for certain towns in the northern Front Range of Colorado.