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Polar vortex hype and confusion


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Posted
  • Location: The Netherlands
  • Location: The Netherlands

    During the last month or so, many different media resources have been talking about the "polar vortex". This has caused many confusion in the general public, as well as with some members here, as it seems. This caught my eye reading some of the posts on different places of the forum. Therefore, I thought it might be a sound idea start a new thread to help solving this confusion.

     

    For example, on Twitter, the following was posted:

     

    Twitter is a hoot just now as US media coverage of the polar vortex goes into overdrive. Read a post yesterday where the news had run with a story - What to do if you are caught in one???

     

    Courtesy to Lorenzo (for finding it)

     

    Moreover, many big news sites in the US have been hyping about this Polar Vortex, without actually explaining what it is. For example a link to a FOX article about this subject can be found below:

    http://www.foxnews.com/weather/2014/01/07/polar-vortex-spreads-into-eastern-southern-us/

     

    Or an even crazier article, stating that the polar vortex is "dangerous":

    http://news.nationalpost.com/2014/01/05/dangerous-polar-vortex-expected-to-bring-record-setting-sub-zero-temperatures-to-more-than-half-of-the-u-s/

     

    It seems like it is evolving toward a serious issue (if it has not already become one).

     

    To start with, some informative links about the Polar Vortex below:

    http://dutch.wunderground.com/blog/JeffMasters/comment.html?entrynum=2604

    http://en.wikipedia.org/wiki/Polar_vortex

     

    I'll try to give a basic explanation later today or tomorrow, if possible.

     

    Any new contribution for explanation of the Polar vortex is greatly appreciated!

     

    BTW: If this has already been discussed, or if it is in the wrong place, please remove or replace it to another subforum.

    Edited by Vorticity0123
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    Posted
  • Location: The Netherlands
  • Location: The Netherlands

    To give a quick start, the polar vortex is a huge low pressure area mainly located over the poles. On the edges of the polar vortex, usually very strong winds are being reached higher up the stratosphere. This can be seen in the graph below, which shows the zonal wind mean:

     

    Posted Image

    Zonal wind mean as analyzed from the ECMWF. On the x-axis, the latitiude is plotted. On the y-axis, the altitude (converted to geopotential heights) is plotted. The colors indicate the mean wind speed (m/s) averaged over the full longitude (or in other words completely circled around the earth) for each latitude. Red is winds from east to west, blue is vice versa.

     

    What can be seen here, for example, is the subtropical jet stream (200 mb, around 40N) but that is currently not the area of interest. The main area to focus on is the very strong wind belt (above 60 m/s) at about 60-70N, above 10 mb (stratosphere). The very strong winds (east to west) originate as a result of the temperature and isobarical gradient between the intense polar vortex (very low pressure and very cold air), and the higher pressure around it (coupled with 'warm' air).

     

    The polar vortex can be seen in the chart below:

    Posted Image

    The chart shows the geopotential height (almost equivalent to pressure) at 100 hPa.

     

    What can clearly be seen is the polar vortex having 2 different lobes, the main one located over Northeastern Canada and the other over Siberia. 

     

    I'll give a more complete explanation later tomorrow, if possible. I hope it helps to improve the general understanding of the polar vortex a little.

     

    EDIT: The main vortex lobe has been placed at Northeastern Canada instead of Greenland given BA's correct remark

     

    Source:

    http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/

    Edited by Vorticity0123
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