Cumulus mediocris is a low to mid level cloud of the cumulus family which does not generally produce precipitation. However they can mature into cumulonimbus or cumulus congestus clouds. They appear in the sky when there is an approach of a cold front, or in today's case, when there is instability in the atmosphere especially when near an area of low pressure.
The towering cumulus cloud known as cumulus congestus achieve vertical development due to areas of convection. This type of cloud is the in-between stage of cumulus and cumulonimbus clouds. These will develop into storm producing cumulonimbus clouds only if there is a enough instability present. They are capable of producing precipitation but they don't always do so.
So with today's scattered thunderstorms, my assumptions seem appropriate, with cumulus clouds maturing throughout the day with vertical development and instability to become storm worthy clouds. Storms should be done by midnight with gradual clearing skies... There is good at the horizon, especially with that high pressure system pushing it's way through!
By: Intern Kristina Oakland
Check out blog at kristinascloudcorner.tumblr.com or follow on twitter @KristinaWXuml