The subsequent MCS developed from several convective elements that formed along mesoscale features of the environment. An unusually strong and deep low-level jet (LLJ) transported exceptionally high amounts of low-level moisture northward very rapidly, destabilized the lower troposphere and generated frontogenetical circulations that appeared to aid convective development. The thermodynamic environment ahead of the developing MCS contained unusually high precipitable water (PW) and very large mid-tropospheric lapse rates. Values for some environmental parameters that are often associated with strong MCSs and severe surface winds, like downdraft convective available potential energy (DCAPE), mean winds, and 0 6 km vertical wind shear, were not as anomalously large as the PW and lapse rates. In fact, the DCAPE was lower than what is typically found in the environment of developing MCSs. The importance of each of these factors in the development of the MCS is discussed.