Southern black widow

I'm no expert but I would guess this to be a young L. mactans. You live in an area with overlap between the northern and southern, and I'm going by the BugGuide info that says the 2 red triangles usually touch to form the hourglass in the southern. As for the abdomen being smaller than what you've seen in photos, that's just because it's young and skinny. They plump up as they grow.