CAPES

I wasn't sure what a CAPE was, but I could tell from the units it was energy per unit mass of air. Here's a definition from typing “define:cape” into Google.

Convective available potential energy (CAPE) is the amount of energy a parcel of air would have if lifted a certain distance vertically through the atmosphere. CAPE is measured in joules per kilogram of air (J/kg). Any value greater than 0J/kg indicates instability, and the possibility of thunderstorms.

From today's weather forecast discussion:

INSTABILITY LEAVES SOMETHING TO BE DESIRED THOUGH...THE FRONT MAY MOVE THROUGH BEFORE CAPES EVEN MAKE IT TO 1000 J/KG. BEST AREA WOULD BE IN OUR SOUTHERN ZONES IN THE AFTERNOON...WE WILL SEE HOW THE MODELS RESOLVE THIS OVER THE NEXT FEW RUNS.