Legend. Surface based CAPE (Convective Available Potential Energy) in Joule/kg = zones in color. Surface based LI (Lifted Index) in deg C = grey lines & values in white boxes. Both gives an idea about the severity of thunderstorms if they are formed. Critical values CAPE: <300              :   little or no convective potential. 300 to1000   :   weak convective potential. 1000 to 2500:   moderate convective potential. > 2500           :   strong convective potential. Tests on the field shows there is no good correlation between CAPE values and severe weather events. (Weak CAPE and strong wind shear may also produce severe thunderstorms). Critical values LI  (not to be used in winter): >0         :  unlike potential for thunderstorms. 0 to -2  :  weak potential, but with trigger (front, trough, orography). -3 to -5 :  moderate potential. < -5       :  strong potential. Tests on the field shows there is good correlation between LI values < -5 and severe weather events.