In the investigated situation a thunderstorm complex developed under ideal circumstances for single thunderstorms; warm and moist air in the lower levels and colder, rather dry air in the higher levels. However there were no indications for dynamical forcing. The system was not under the influence of the Cold Front nor the associated jet. Also the vertical windshear was not of great dimensions. Although the storm over the Netherlands was not extensive, it was a fierce one with very strong downbursts.

Why the more southerly cloud cluster decayed so suddenly in the evening is not totally clear. An explanation might be the fact that this cluster was in the slipstream of the northerly one, with sinking air behind it and a colder earth surface. The complex over Biscay fitted the concept of an MCS much better, was active in a much larger area and strongly under the influence of the dynamical fields in the area of the Cold Front.