SECLUSION PROCESS

During the process of rapid cyclogenesis (q.v.), the standard 'Norwegian' theory of development leading to an occluded front is not appropriate. What appears to happen is that the original cold front becomes weak/ill-defined (close to the low centre), and a new cold front appears further to the west. (This is effectively what has been drawn in the past as a 'back-bent' occlusion). So, what happens to the warm air associated with the warm frontal zone near the low centre? Around and immediately to the equatorward side of the low, it becomes trapped or 'secluded' from the rest of the development in a discrete region enclosed by relatively colder air encircling the development - a so-called 'seclusion'. (This is therefore a different process from that producing the classical 'occlusion' whereby warm-sector air is lifted by the advancing cold air.)