Horizontal moisture advection primarily contributed to a substantial increase in convective available potential energy (CAPE) and decrease in convective inhibition (CIN) during the 4 hours prior to the arrival of the squall line. Parcels encountering the southwestern OFB required approximately 100 km of northeastward travel past the OFB to be lifted to their LFCs and to enter convective updrafts. Numerical simulations that placed the MCS at varying distances too far to the northeast were analyzed, and MCS displacement error was found to have been connected to under-prediction of low-level moisture and subsequently over-predicted convective inhibition. The over-predicted CIN in models resulted in northwestward moving air parcels requiring unrealistically long residence times and northeastward travel in regions of gradual meso-alpha scale lift before these parcels initiated convection. These results suggest that erroneous MCS predictions by NWP models may sometimes result form poorly analyzed low-level moisture fields.