Cold drop

The Cold Drop is a phenomena that appears when a front of very cold polar air, called jet stream, advances slowly over Western Europe, at high altitude (normally 5-9 km or 3-5.5 mi). If a sudden cut off in the stream takes place, caused by various motifs, like the effect of the high pressures, a bag of cold air detaches from the main jet stream, penetrating to the south over the Pyrenees Mountains into the Spain's warm air.