1. A method for modeling behavior in a process plant, comprising: receiving M process variable data sets, wherein M is an integer; calculating statistical data for process variables associated with the M process variable data sets using the M process variable data sets and not using additional process variable data sets; scaling the M process variable data sets using the statistical data; calculating, using a computing device, a plurality of intermediate modeling terms using the scaled M process variable data sets; storing the plurality of intermediate modeling terms in a memory of the computing device; receiving additional process variable data sets associated with the process variables; scaling the additional process variable data sets using the statistical data; after calculating the plurality of intermediate modeling terms using the scaled M process variable data sets, updating, using the computing device, the plurality of intermediate modeling terms using the stored intermediate modeling terms and the scaled additional process variable data sets, and without using the M process variable data sets; and calculating, using the computing device, a model of at least one of the process variables associated with the M process variable data sets using the updated plurality of intermediate modeling terms.