The values of the pseudo-adiabats increase with height. Assuming there is sufficient moisture for parcels to rise along moist adiabats, CSI would occur at point A. For parcels rising along the moist adiabat, the value of M would increase as x decreases. Another way to evaluate the potential for CSI is to look at the slope of the lines. My personal experience is that CSI will occur if the lines of absolute momentum and pseudo adaiabats are parallel, especially when using model data. At point B CSI will not occur.
SI occurs when parcels rise along dry adiabats.
The same logic is used as in figure 2, except the pseudo adiabats are replaced with dry adiabats and there is insuffcient moisture for parcels to move along moist adiabats. The IR picture, 300mb winds, and 300mb isotachs at 1200 UTC show a strong jet streak over Utah. Plan views of winds at other levels are not shown, but there was little directional vertical wind shear in the region with banded clouds. A cross section from CNY to ALS is perpendicular to the winds and the mean layer thickness. In this region the horizontal anticyclonic wind shear is very strong as indicated by the nearly horizontal M surfaces, especially in the right half of the cross section.