Siberian Express is a shorthand meteorological term in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 describing the arrival of an extremely cold air mass

Air mass

In meteorology, an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of square miles, and adopt the characteristics of the surface below them. They are classified according to latitude and their continental or maritime...

 of Arctic

Arctic

The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...

 origins. It does not necessarily refer to an origin in Siberia

Siberia

Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

. The term is most commonly employed by the news media when such a frigid air mass moves into areas where it is relatively unusual, such as the Deep South

Deep South

The Deep South is a descriptive category of the cultural and geographic subregions in the American South. Historically, it is differentiated from the "Upper South" as being the states which were most dependent on plantation type agriculture during the pre-Civil War period...

 or Eastern Seaboard

East Coast of the United States

The East Coast of the United States, also known as the Eastern Seaboard, refers to the easternmost coastal states in the United States, which touch the Atlantic Ocean and stretch up to Canada. The term includes the U.S...

 of the United States. Meteorologically, it is typically associated with a phenomenon called the Pacific-North American teleconnection pattern

Pacific-North American teleconnection pattern

The Pacific-North American teleconnection pattern is a climatological term for a large-scale weather pattern with two modes, denoted positive and negative, and which relates the atmospheric circulation pattern over the North Pacific Ocean with the one over the North American continent.The positive...

 (PNA).

See also

• Siberian High
  Siberian High
  The Siberian High is a massive collection of cold or very cold dry air that accumulates on the Eurasian terrain for much of the year. It reaches its greatest size and strength in the winter, when the air temperature near the center of the high-pressure cell or anticyclone is often lower than...
  
  
• Cold wave
  Cold wave
  A cold wave is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in temperature within a 24 hour period requiring substantially increased protection to agriculture, industry, commerce, and...
  
  
• Cold front
  Cold front
  A cold front is defined as the leading edge of a cooler mass of air, replacing a warmer mass of air.-Development of cold front:The cooler and denser air wedges under the less-dense warmer air, lifting it...
  
  
• Pineapple Express
  Pineapple Express
  Pineapple Express is a non-technical term for a meteorological phenomenon characterized by a strong and persistent flow of atmospheric moisture and associated heavy rainfall from the waters adjacent to the Hawaiian Islands and extending to any location along the Pacific coast of North America...
  
  
• Pacific Organized Track System
  Pacific Organized Track System
  The Pacific Organised Track System comprises airways used primarily for travel between Japan and Southeast Asia and the mainland of the United States.Similar to the North Atlantic Tracks, PACOTS routes are flexible due to jet streams....