Predictions of MCS symmetry and movement play a significant role in determining precipitation amounts
Possible cause of asymmetry
1) The Coriolis force acting upon the ascending front-to-rear flow turns the flow to the north, leading to an accumulation of hydrometeors and buoyancy
2) The Coriolis force acting on the surface cold pool helps drive cold air south leading to new cell generation
3). Position of low-level jet and strongest instability.
Loerer and Johnson, Mon. Wea.Rev. 1995