The other two elements of the omega equation state that rising motion is favoured by warm air advection and diabatic heating. Their effect is largest along the warm front or in the warm sector of low pressure. The most unstable air mass is usually located on the warm side of a frontal zone. The existence of a low-level jet (LLJ) in the warm sector may further increase the threat of severe thunderstorms by providing a considerable amount of low-level shear. A low-level jet is a wind speed maximum (of at least 15 m/s) in vertical wind profile in the lowest 1 or 1.5 km layer AGL. LLJs are typically observed in the warm sectors but also in front of warm fronts and behind occlusion fronts. A LLJ can enhance the advection of warm and humid air which may ultimately result in the removal of the convective inhibition (i.e. breaking of the cap).

A forecaster should closely monitor events in the lower troposphere in those cases which have high instability but no approaching upper-level trough or pronounced jet streak. In other words, severe convection may well develop under anticyclonic upper-level flow if high instability and at least moderate deep layer wind shear are present.

what is the relation between the lower troposphere and such events?

what is the relation between such events and anticyclonic upper-level flow?