Frozen USA but warm Europe, why weather seesaws across the globe - Tucson News Now

Frozen USA but warm Europe, why weather seesaws across the globe

As parts of the United States plunged into a deep freeze, other parts of the globe were running warm to start 2014. 

This phenomenon is not unusual. 

The atmosphere is in constant flux but must follow the laws of physics, specifically the fact that energy cannot be created or destroyed.  

The total amount of energy driving weather across the world does not change, it simply shifts from one area or one form to another.  

It is this shift of energy that caused a big contrast in weather across the Northern Hemisphere the first week of 2014. 

According to NASA "One of the underlying features connecting seemingly opposite weather outbreaks are giant meanders in high-altitude winds known as Rossby waves. These planetary-scale waves define the jet stream and do much to determine the type of weather any given area will face over periods of days to weeks."

These waves in the jet stream drove the polar vortex away from the North Pole and down into the Great Lakes and Southeast areas of the United States.  

At the same time warm air slipped north in Europe and Russia to replace the movement of the cold air. 

According to NASA this made "holiday celebrations rainy rather than snowy and prompted discussions about whether there will be enough snow for the upcoming winter Olympics in Sochi, Russia."

You can see this contrast in the images from NASA Earth Observatory below. 

The top map above shows land surface temperature anomalies in North America for January 1–7, 2014. Based on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite, the map depicts temperatures for that period compared to the 2001–2010 average for the same week. Areas with warmer than average temperatures are shown in red; near-normal temperatures are white; and areas that were cooler than the base period are blue. Gray indicates areas where clouds blocked the satellite from collecting usable data. The second map, based on the same MODIS data, shows temperature anomalies in Europe for the same period.


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