Hartman Long Range
The image below shows frontogenesis (red), omega (blue), with forecasted precipitation (6h qpf, GFS 211 12Z 3/30/2012) at 00Z on 4/6/2012 (6 pm, Thrusday 4/5/2012). We can see that precip is located behind the frontal zone with upward motion occurring ahead of the frontal zone.
This next image shows the 305 isentropic surface for the same forecast time (F156 from GFS 211 12/30/2012 12Z). We can see there is high pressure advection, offering good isentropic lift, aligning over the frontal zone and correlating with the largest amounts of forecasted precip. The 2nd isentropic analysis shown shows the 310 K surface and tells a similar story. Isentropic surfaces where chosen for analysis so as to mitigate the topographic affects in the frontal zone.