Actinoform cloud

But until the late 1990s, scientists had dismissed them as merely a relatively uncommon transitional form between open- and closed-cell formations of stratocumulus clouds.

In fact, the term "actinoform" is not included in the 2000 edition of the Glossary of Meteorology, which is considered to be the comprehensive reference work for meteorologists.

Such cloud systems are persistent year-round off the coast, yet in certain seasons they blow ashore and create the "June Gloom" effect on land.

Meteorology professor Bjorn Stevens of the University of California, Los Angeles theorizes that they, in conjunction with open-cell stratocumulus clouds, are associated with drizzle formation.

Thus, data from recent field studies suggest that the presence of "pockets of open cells" (POCs) and actinoform clouds is related to the onset of precipitation.