Confused about the #PolarVortex? Usually a strong jet stream confines Arctic air to the north, stabilized by a big difference in temperature between low and high latitudes. The smaller the difference in temperature, the more the wind belts meander (Via @RemoteLongitude & @NOAA)

Because of man-made #climatechange, the poles are heating faster than the rest of the planet, diminishing the temperature difference and weakening the jet stream. This also means that weather patterns - periods of itense rain or drought - are locked in for longer periods of time

..and whilst much of the USA is gripped by bitter cold, other parts of the globe are unusually warm, confirming the overall #globalheating trend (via @WMO).