Winterymix - convection intensity over the open ocean doesn't vary much day/night since sea surface temperatures have very little diurnal variation. However convection over the land not far from the LKP would decrease overnight leaving more 'airspace' over the adjacent sea for CBs to develop and peak towards dawn (without going into the broader scale MET dynamics). Also, the developing phase of CBs is the most active in terms of turbulence/hail/lightning/vertical motion so it's the brand new (towering CU/CB) cell which has just become visible to radar which is often the most dangerous.