Why No Snow For The River Valley?

Why did the snow stay to the north in extreme northern and eastern parts of Benton County?  Then it looks like the snow zones will set up to the south later tonight.  Why does it jump over the majority of the River Valley???

In order to get snow, a lot of factors need to come to play. The best way to get some snowflakes is to have rising motion in the upper levels of the atmosphere, coupled with a surface boundary like a cold front.

On Monday, everyone felt the cold front push through. However, only Northwest Arkansas had good upper level rising motion, thanks to jet level dynamics (Right-Entrance Divergence aloft).

Over the River Valley, there isn't much lifting in the atmosphere to help the snow bands to develop.

To the south, south of Poteau and Waldron, there is more rising motion, but due to different forcings.  There is some Q-Vector Convergence (700 hPa) and Isentropic Lift at 300K.  This, coupled with the cold front, will provide a decent snowfall across central and southern Arkansas.