The Doppler radar site that covers our area (a good part of eastern PA and much of NJ), is being upgraded by February 2012. This upgrade will allow Meteorologists to detect and measure rainfall and storms with much better accuracy. In some instances, a developing tornado can hide within a rain wrapped storm. This new technology will help increase warning time to the general public.
Here is a youtube video from the National Weather Service which gives a good idea of the impact this technology will have on forecasting.
On a final note, looks like rain is on its way. The NWS has posted its forecast, rain for Monday and Tuesday.