Reply To: Sky and cloud questions?

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#290085
Michael Lerch avatarMichael Lerch
Participant

Hello Ramona,   Nice capture with the camera, but no, imho, what you’ve photographed isn’t AltCum lacunosus.  I believe you caught deteriorating altostratus  or even a lower stratus. My understanding of the  difference between lacunosus and deteriorating stratus is,,lacunosus is formed when colder air drops in altitude..the key might be..” forms”. When stratus deteriorates,,it is coming apart, evaporating back to gaseous state when warmer atmosphere rises through the stratus. Lacunosus  condenses out of the atmosphere, forms. What I’ve seen is usually  a uniform altitude, or sheet of lacunosus. Deteriorating stratus or even deteriorating lenticular is pushed and rounded as the cloud evaporates from rising thermals. The gallery has examples of lacunosus. My experience has been that lacunosus has no real herald, nothing hinting at its entrance. It just happens. Only a few times has it been literally out of a clear blue sky. Most of the time lacunosus has been part of a hurly burly mix of a system sweeping though. Most of my observations have been of small to medium patches of sky especially at alto altitudes. Tip of little finger to tip of thumb of an outstretched hand ( or less) is a small patch of cloud to me. That distance is also roughly 20degrees a way to measure halos distance from sun, and for star gazing at night. When you see Lacunosus you will know it. Look for a uniform horizontal sheet of it, maybe even under a thin asperitas event. Have fun!