Dopplar can't be effective past a certain range. Due to the curvature of the earth are other limiting factors radar can't see past a certain point. Imagine looking out towards the horizon. You know there is more behind there but can't see it. I think the range for most of the NWS products is ~140 miles. You can learn more here. http://www.srh.noaa.gov/srh/jetstream/doppler/radarfaq.htm

As for recon. It can give us many things that satillites can't. Presice temperatures, pressures, dewpoints, wind readings and they also conduct research missons to better understand these storms. Also getting information about the environment gives the models more data for their runs. It is also interesting to see how close the estimates made are to they actual conditions. It gives a check to the accuracy to current determinations that are made remotely.

The advice given earlier on both accounts is very good and would be very wise to heed