Question

these clouds are large mid-level blueish clouds that often spread over large area and are typically featureless​

Answer 1

Altostratus

Step-by-step explanation:

Altostratus appear as gray or bluish-gray sheets of cloud that partially or totally cover the sky at mid-levels.

Answer 2

Step-by-step explanation:

Altostratus clouds are large, mid-level, gray or blue-gray clouds that often spread over a large area and are typically featureless. They are composed of ice crystals and water droplets and usually cover the entire sky. The sun or moon may shine through an altostratus cloud, but will appear watery or fuzzy. If you see altostratus clouds, a storm with continuous rain or snow might be on its way.