Really easy mod. Simply hook up a X10 powerflash module to the speaker output of the NOAA weather radio. Some weather radios already have an external contact closure provided. If your unit does, set the powerflash input switch to "B". If not simply connect the input to the speaker output of the radio and set the powerflash input switch to "A".
The powerflash is very versatile and can be set to turn all lights on, or just a specific unit, or flash the lights.