Its our first diagram in awhile!
What we look for when it comes to storms and tornado potential and discerning how big of a threat is present is straightforward:
-Is there a lowered area underneath the updraft that’s persistently present with consistent upward motion into it?
-Is there an area under the updraft (preferably the lowered area) with persistent rotation that lasts more than a couple of minutes?
If the answer to both of these is yes, then the tornado potential for a storm is relatively high. If a lowering is present but not rotating or if the base is rotating with no lowering — that doesn’t mean a tornado can’t form, just its probably a lower chance than if both items were present when it comes to a typical supercell tornado evolution.