Cloud Coverage

The infusion of Aviation Weather Center NSHARP has provided potential cloud displays based off of Chernykh and Eskridge (JAM 1996) and Fred Mosher's cloud algorithm. Both algorithms are highly sensitive to vertical changes in T/Td/RH, and they can sometimes miss saturated layers because of this.

Chernykh and Eskridge Derived Clouds

OVC - overcast (80-100%)

BKN - broken (60-80%)

SCT - scattered (20-60%)

yellow - cloud layers

The algorithm relates cloud amounts to functions of temperature and dewpoint depression. It uses second derivatives of temperature and relative humidity in the vertical.

Mosher Derived Clouds

red - cloud layers

The algorithm relates cloud base and top to dewpoint depression (4.5C threshold). It uses a second derivative of dewpoint depression in the vertical. The method involves a top down approach where cloud top is related to dewpoint depression increases with height. Cloud base is computed from the lowest level of dewpoint moistening (where dewpoint depression decreases with height) lifted to the LCL.