BBT charting done right?

Good morning all. Quick question. Sometimes charting can get me a little confused. According to my chart, yesterday my temp skyrocketed to 98.47. This morning, it plummets to 97.41. Average cycle is about 28-30 days and this is CD12 today. If my temp from this day forth continually rises, does that mean that I am most likely going to ovulate in the next 24-48 hours? S/n: clear blue digital ovulation monitor started my fertility was high and an opk stock started the same this morning.. Have a good day everyone!