WeatherCall is a subscription-based service from KIMT (Iowa/Minnesota TV station) based on the U.S. National Weather Service data. It costs $6 dollars per year. Subscribers provide a physical location (address) and receive notification (e-mail, text, phone call) whenever severe weather including tornado warnings are delivered. Subscribers can optionally choose to receive severe thunderstorm and flash flood warnings.
The service is enabled by changes in how NWS know tracks storms. It's now done via polygon - meaning those outside the area need not be warned. Messages come from the station's Chief Meteorologist Adam Frederick 24 hours a day. It's not a location-based service in the sense it does not know where you are, save via that single input address. When you travel you can change your location manually within the system.
The company behind the offering (which apparently is apparently available from many TV/radio stations) is
Media Weather Innovations.