Why do long term regional climate simulations have reduced atmospheric moisture and precipitation in the Great Plains?
James Correia Jr., PNNL, Richland, WA ; and L. R. Leung Reduced water vapor mixing ratio in the Great Plains has been seen in two realizations of WRF regional climate simulations when compared to reanalysis and observations. We hypothesize that poor representation of the model LLJ ranging from poor positioning and orientation to winds that are too SW aloft, and late onset of the inertial oscillation, is to blame. Analysis indicates that strong LLJs are negligible at 0000 UTC while by 0600 UTC strong LLJs make up roughly half of all LLJs and have nearly the same spatial pattern. Further analysis will detail the LLJ characteristics such as orientation, persistence, onset and duration within the model. With insufficient moisture transport by the LLJ to the Great Plains, precipitation is shifted eastward out of the Plains, hence missing the precipitation over the Midwest and points further south and southwest. Another plausible explanation for the moisture deficit in the Great Plains is th
