Editing Altostratus cloud (section)

== Use in forecasting ==
{{see also|Weather forecasting}}
Altostratus clouds tend to form ahead of [[warm front]]s or [[occluded front]]s and herald their arrival.<ref name="MetOffice" /> These warm fronts bring warmer air into the region. Occluded fronts form when a faster-moving cold front catches up to a warm front, and the temperature after the frontal system passes may rise or fall.<ref name="frontal-systems">{{cite web|url=https://scied.ucar.edu/learning-zone/how-weather-works/weather-fronts|title=Weather Fronts|publisher=University Corporation for Atmospheric Research|access-date=28 March 2022|website=Center for Science Education}}</ref> As the frontal system approaches, cirrostratus clouds will thicken into altostratus clouds, which then gradually thicken further into nimbostratus clouds.<ref name="MetOffice" /><ref name="ahrens-120"/> If the frontal system is occluded, [[cumulonimbus cloud]]s may also be present.<ref name="frontal-systems" /> Once the altostratus clouds have arrived, rain or snow will usually follow in the next 12 to 24 hours.<ref name="ahrens-120"/>

Instability in the atmosphere can embed [[Cumulonimbus cloud|thunderstorms]] in an altostratus cloud,<ref name="WMO-Desc" /> although altostratus clouds themselves do not produce storms.<ref name="Cloud-Classification" />