Cierzo

The cierzo is a strong, dry and usually cold wind that blows from the north or northwest through the regions of Aragon, La Rioja and Navarra in the Ebro Valley in Spain. It occurs when there is an anticyclone in the Bay of Biscay and a low-pressure area in the Mediterranean Sea. It is more common in autumn and winter, when larger pressure gradients occur, but a small pressure difference along the... (Wikipedia)