by FLPhotoCatcher » Wed Oct 24, 2012 7:42 am
florid_snow, I read the abstract in the link, and do not agree, though I think the standard explanation for the formation of mammatus clouds may not be complete either. To me, it's clear that mammatus clouds are not formed just from the heating of the underside of anvil clouds. If that were the case, then most anvil clouds over warm dry land would grow them.
I have seen them in Florida several times, and Florida is usually quite humid, and seemed to be at the times. Most every time, they formed under the anvil of a severe storm. The main differences between the anvil of a severe storm and the anvil of an average storm, is its thickness, and the height of it. The thicker an anvil cloud is, the more precip (in the form of snow) there is, and the more precip there is, the more and stronger the downdrafts are. These downdrafts may indeed have to be above air that is drier than average. When the downdrafts hit the drier air, the snow sublimates and contributes moisture to the dry air, thus making the air around the downdraft lobe more buoyant, and causing it to rise around and between the lobes. Heat radiation from the ground may add to the buoyancy of the outsides of the lobes. In a house fire, you will get flames below the ceiling that look similar when "flashover" occurs (google flashover to see some pictures). These flames that look like mammatus clouds are caused by cooler and denser flammable vapors (smoke) falling down from the ceiling and then igniting on contact with oxygen and existing flame.
florid_snow, I read the abstract in the link, and do not agree, though I think the standard explanation for the formation of mammatus clouds may not be complete either. To me, it's clear that mammatus clouds are not formed just from the heating of the underside of anvil clouds. If that were the case, then most anvil clouds over warm dry land would grow them.
I have seen them in Florida several times, and Florida is usually quite humid, and seemed to be at the times. Most every time, they formed under the anvil of a severe storm. The main differences between the anvil of a severe storm and the anvil of an average storm, is its thickness, and the height of it. The thicker an anvil cloud is, the more precip (in the form of snow) there is, and the more precip there is, the more and stronger the downdrafts are. These downdrafts may indeed have to be above air that is drier than average. When the downdrafts hit the drier air, the snow sublimates and contributes moisture to the dry air, thus making the air around the downdraft lobe more buoyant, and causing it to rise around and between the lobes. Heat radiation from the ground may add to the buoyancy of the outsides of the lobes. In a house fire, you will get flames below the ceiling that look similar when "flashover" occurs (google flashover to see some pictures). These flames that look like mammatus clouds are caused by cooler and denser flammable vapors (smoke) falling down from the ceiling and then igniting on contact with oxygen and existing flame.