I expect the warnings to include the midlands later, especially the north midlands.
Look at this 6z NAE chart:
The potential is there for falls of several cm, as much as 20cm over the highest hills (basically the tops of the Pennines, Peaks and Moors)
I mentioned in the cold discussion thread that it might be due to the Met Office thinking the midlands might escape with just a dusting, not enough to warrant a warning.
Best stay tuned to forecasts and the MetO website - I for one am expecting the N Mids (at least) to be included in the warning area.
The BBC forecast I saw last night showed parts of the Midlands affected by the snow pushing southwards tonight.