FDX/UPS plus Weather

I get done with a trip this evening in DTW. I'm expecting my evening flight to OKC will cancel because of the winter storm in OKC. How likely is it that UPS or FDX will go to OKC in the morning with weather? I am planning on taking one of the two, (whoever has seats). However, I'm wondering if I will end up stranded in MEM or SDF. Also, how proactive are they in these scenarios? If I call about 7pm eastern tonight will they already have an idea?

Thanks everyone!