By Geoff Bansen

PHILADELPHIA (CBS) — After another beautiful weekend, the threat of rain returns to the Delaware Valley.

Clouds will mix with some sun throughout the day with the slight chance of a shower or thunderstorm, as the Delaware Valley sits ahead of a cold front. This front will gradually slide further east and move through during the day on Tuesday, bringing showers and thunderstorms to the region. The threat is low, but there is a marginal risk that a few of these storms could be severe. It will be, by far, the worst day of the week as conditions will be dry and favorable once the front passes.