Decision to call this a significant tornado episode has been in the works for a day or two, although confirmation was only made in the last few hours. Latest analysis of predicted helicity and instability in the nation's heartland tells me that Sunday evening may contain multiple strong tornadoes. It is for this reason that tomorrow is going to be a Critical Storm Action Day (CSAD), which means all resources here at The Weather Centre will be devoted to covering this event.
High resolution models support the idea of scattered rotating supercells developing tomorrow evening in a development that will lead to tornado development. Additional products with a tornado mask indicate that central Oklahoma will have incredible potential for strong, long-lived tornadoes tomorrow. At this point in time, based on predicted reflectivity across the Plains, we should see some spectacular supercells tomorrow evening that are more than likely to produce a very formidable tornado threat in the areas shaded in red in my map above. If you are in the shaded red area above, I highly advise you to be ready to take cover from what could be a strong tornado (EF3 or stronger). However, always heed the words of the National Weather Service over this blog.