List of Cloud Types - Alphabetical List WMO Tropospheric Species

Alphabetical List WMO Tropospheric Species

• Castellanus – castle-like with a series of turret shapes – indicates air mass instability.
• Congestus – great verticsal development and heaped into cauliflower shapes – indicates considerable airmass instability and strong upcurrents.
• Fibratus – thin filament type clouds, can be straight or slightly curved.
• Floccus – looking like a tuft of wool – indicates some mid and/or high level instability.
• Fractus – irregular shredded appearance – forms in precipitation and/or gusty winds.
• Humilis – small, low, flattened cumulus – indicates relatively slight airmass instability.
• Lenticularis – having a lens-like appearance – formed by standing waves of wind passing over mountains or hills.
• Mediocris – medium size cumulus with bulges at the top – indicates moderate instability and upcurrents.
• Nebulosus – indistinct cloud without features – indicates light wind if any and stable air mass.
• Spissatus – thick cirrus with a grey appearance – indicates some upward movement of air in the upper troposphere.
• Stratiformis – horizontal cloud sheet of flattened cumuliform cloud – indicates very slight airmass instability.
• Uncinus – cirrus with a hook shape at the top – indicates a nearby backside of a weather system.