The correct answer is 61.
TT = (T850 + T
d850) - (2 * T500)
= (18 + 13) - (2 * (-15))
= 61
Note the Total Totals index value also appears in the parameters listing to the right of the plotted sounding on the Interactive Skew-T.
Incorrect. Recall from the table on the definitions page that a Total Totals index of 55 or greater indicates that severe thunderstorms are likely, with
possible tornadoes.