Answer:
You have just driven across the Cold front.
Step-by-step explanation:
Weather Front:
In Meteorology, weather fronts are simply boundaries between two air masses of different densities. There are four weather fronts and one of them is cold front and other fronts are warm front, stationary front and occluded front.
Cold Front:
In Meteorology, cold front is a boundary of cold air mass that is advancing under the warm air mass.
In our scenario, as the driver was moving in the west and he listened on radio, the next country on north is under tornado warning. So, when he passed the cold front, he experienced the conditions described.