Temp rise without positive opk

Can you ovulate and have temp rise without a positive opk? I typically have very normal 30 days cycles. Last month was my first month charting bbt. I ended up ovulating cd 29. Confirmed with opk and temp rise. Which made it a long cycle for me. This month I had a temp rise cd11 and ff is giving me cross hairs but my opk hasn't been positive yet. The line is dark but not as dark or darker then control line. I normally have a week or so of dark opk before it actually turns positive. I thought temping would make me more confident but it actually confusing me more.