Explanation:
What kind of cloud is this?
A roll cloud.
These rare long clouds may form near advancing cold fronts.
In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud.
When this happens uniformly along an extended front, a
roll cloud may form.
Roll clouds
may actually have air circulating along the long horizontal axis of the cloud.
A roll cloud is not thought to be able to morph into a
tornado.
Unlike a similar
shelf cloud,
a roll cloud is completely detached from their parent
cumulonimbus cloud.
Pictured above, a roll cloud extends far into the distance in the
summer of 2005 above
Albany,
Missouri,
USA.
