METEOROLOGIST JEFF HABY
ThetaE involves the combined effects of heat and moisture. The ThetaE value is found by taking a parcel of air, releasing the latent heat
of moisture in the parcel and then brining the parcel to the 1000mb level. An increase of moisture will increase the latent heat released
and will thus increase the ThetaE. An increase of temperature will also increase the ThetaE. Two of the important ingredients for
thunderstorm development are heat and moisture. The ThetaE is an important index since it combines both heat and moisture into one
index value. A chart of ThetaE can be produced, and from the chart the regions or axes with higher ThetaE have an increased chance
of being the trigger point for convective uplift. Heaviest rain can also occur in the regions or axes with a higher ThetaE.
The chart below shows several factors that can increase ThetaE. Two common ways the temperature can increase is from solar heating and warm air
advection. Moisture can increase from moisture advecting in from a moisture source. Moisture can also increase when a convergence axis forces
moisture to merge closer together which results in a greater moisture density and thus an increase in dewpoint. Thus, convergence boundaries
are common regions in which convective uplift begins.


