Abstract
One of the most important forecasting problems over the eastern Atlantic Ocean is the prediction of rapid cyclogenesis culminating in storms of full hurricane intensity. Such events happen about 3–5 times per cold season. Numerical prognoses conspicuously fail to anticipate these intense developments. On the other hand, a very characteristic shape appears in satellite imagery in the early stage of deepening, or even sooner, when nothing except a very weak wave is seen on the surface map. The cirrus cloud configuration resembles a solid cloud head, sharply separated from all other cloud types present. Statistical investigation of the period 1968–73 indicates that all extratropical hurricane developments of the eastern Atlantic, and therefore within reach of the Berlin satellite facility, were preceded by the appearance of such cloud heads, and that no heads occurred without being followed by major deepening at the surface.
