Make sure you get a weather alert radio with SAME technology. For example, all the counties around me are assigned a Specific Area Message Encoding (SAME) number. To set the radio up, I had to decide what codes I want to activate in the radio. And since I live adjacent to another county that wraps North and West of us, I wanted alerts for that county as well as the one where I live. This is because 99% of the storms we get come from the SouthWest, West and the South in that order. I then tune the radio to the National Weather Service station covering my area and added the SAME codes and whenever a watch or warning is activated for those counties I've added, I get the annoying but possibly lifesaving alert. Alerts for other counties don't set off the alarm.
BTW, I have a Davis Advantage Pro2 weather station. The other night when we had those horrific tornadoes here in Middle Tennessee, which we were spared, but our neighbors to the NorthEast weren't, the only thing I saw was the winds go from calm to 65 MPH in just a few seconds, blowing from different directions, a sudden drop in barometric pressure and a drop in temperature. This is all well and good, but what it seems to indicate is that a violent storm that could produce a tornado is upon us, giving us precious seconds to take cover.
A much better scenario IMHO, is to have the National Weather Service, who monitors these storms 24 x 7, alert us of watches and warnings. I then turn on the TV/Radio to get more detailed info, and prepare accordingly. But of course I don't just depend on the NWS radio. I usually know beforehand when bad weather is coming our way (NWS, weather.com, etc) and take action accordingly.
And here are some links on the SAME technology...
NOAA Weather Radio
NOAA Weather Radio SAME Info
NOAA Weather Radio