Recent studies have shown that drought conditions in the United States of America experience interannual and multidecadal variability. Factors affecting drought variability over these time scales are not well understood, however. It appears that the Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO) and increasing Northern Hemisphere temperatures influence multidecadal drought frequency. To expand our current understanding of how these processes impact drought, time bias corrected monthly temperature, precipitation and drought index from various climatic sub-divisions for the 1895 to 2006 period are decomposed into annual, interannual and multidecadal components using a series of filters that employ locally weighted regression. Each of these components is then compared with the three aforementioned explanatory processes as well as the El Niņo-Southern Oscillation (ENSO) phenomenon. Ordinary, partial and semi-part correlation coefficients are used to quantify the nature of the relationship between explanatory and dependent variables and to ascertain whether one of the explanatory processes is more important than the others.