Feb 24 2011 Snowfall or lack there of?!?

Regional Radar at 10pm CT Feb 24 2011

When looking at the current radar one would think there would be a lot of snow coming down across northern illinois, but little is falling and snowfall totals will likely be a lot lower than initially thought.  One of the reasons why the snow is struggling to accumulate at the surface is due to the intrusion of dry air at the surface. This is evident when looking at the surface observations across Northern Illinois (seen below).

Surface observations as of 9pm CT Feb 24 2011

The dew point at the surface (the green numbers) in some cases is 5 to 10 degrees below the actual air temperature (the red numbers ).  The significance of this difference is due to the fact that the dew point must be equal to the air temperature in order for the air to become saturated to support precipitation to reach the surface in liquid or frozen form.  Until the air becomes saturated snow will be non-existent or very light in nature.  Another potential reason for the lack of snow and moisture with this system is likely due to the strong thunderstorm activity along the gulf coast where they are dealing with severe thunderstorms, frequent lightning, hail and even tornadoes.   These storms are taking a lot of the moisture that is being transported from the south to the north so most of the energy with this system is being used by the thunderstorms along the gulf.  This can be observed on the isentropic analysis, which shows moisture transport (shown below).

The darker greens represent high moisture content in the atmosphere.  Therefore, based upon this image one can see that most of the moisture is right along the gulf and southern states where most of the severe weather is occurring inhibiting some of the moisture from making it to Northern Illinois to support heavy snowfall.

Same radar image as shown previously.  I am just emphasizing the strong storms in the south.