Significant low-level moisture moved westward into the foothills Saturday night behind a weak cold front. Dewpoint temperatures in the 60s in Colorado Springs is significant and only happens a few days each year. Many areas east of the mountains woke up to low cloud cover as result of the moist air.
The moist air at the surface acts as fuel for thunderstorms, and, when combined with several other atmospheric instability factors, can be analyzed as potential energy for thunderstorms. Storms often develop on the edges of significant pools or areas of increased energy. Today in Colorado this will be along the eastern foothills and terrain will help to initiate storms in the early afternoon as a southest surface wind pushes into the terrain features west of the Interstate.
The greatest severe weather threat on Sunday is large hail between 1.5″ and 2.5″ in diameter. Storms will tend to split into separate updrafts early in their life cycle today. Often-times the southern storm of the split is the stronger of the two storms and these will be more likely to produce the largest hail, particularly the more south they tend to move.
As storms move east onto the plains and into the axis of greatest moisture and available energy, the chance for large hail will increase. This threat is represented by the hatched area below in the severe weather threat for Sunday. Storms may also become more likely to produce damaging wind gusts near 70mph as they cluster up over the eastern plains.
Storms should be mostly east of the Interstate by 5 p.m. and any lingering or trailing storms behind the initial wave will be weaker than earlier storms.