A convective limiting factor is a factor that prevents convective thunderstorms from occurring. This writing takes a look at several factors that can prevent convective storms. Relatively cold air in lower troposphere: Solar radiation warming of the ground surface is often an important ingredient for convection. If the lower troposphere is too cold, this can prevent convection. This can occur from a thick cloud deck that limits solar radiation, nighttime when there is no solar radiation, and a cold front that brings in cold air and stabilizes the lower troposphere. A strong capping inversion: A strong capping inversion is relatively warm air aloft that prevents convection from the lower troposphere from penetrating the inversion layer. If the cap holds strong even with daytime heating of the ground surface, convection will not occur. Forecasters note how strong the cap is and compares that to the lifting mechanisms and solar heating in order to determine if the cap will prevent storms from occurring. Lower troposphere too dry: Updrafts need moisture to be unstable. If moisture is low, the rising parcels of air will be too stable to cause convection if a cap (and in many cases even a weak cap) is in place. The latent heat from rising saturated air helps the rising parcels to be more unstable. Forecasters look at dewpoints at the surface and the moisture profile in the lower troposphere to assess how moisture will add or subtract from the convective potential. High pressure dome: Being near the center of a synoptic high pressure dome can greatly limit the convective potential. This is because the air is sinking and stabilizing. These high pressure systems help produce a capping inversion, help dry out the atmosphere and make the atmosphere stable. |