While we wait for our first real winter threat, I thought it would be fun to do a post on one of the most epic -EPO (McFarland's signature) episodes of our lifetimes (probably most severe since 1899).
That of course is December of 1983. Can't go through a December without talking about this once in a lifetime event!
On December 11 of that year you wouldn't know that the biggest EPO blocking episode was about to unfold. Just run of the mill 500mb and a cold front. However the seeds of the event was being planted North of Alaska with arctic HP dome setting up
Then around mid month massive ridge off the west coast sends a significant front, though not true arctic in nature it was very cold for December.
Then around the 18th massive 500mb ridge 564dm began marching towards Alaska and sent down the Arctic/Siberian air mass that plunged the lower 48 into a deep freeze. Though severe this was not yet the apex of the event.
Just before Christmas the 500mb ridge "popped" over Alaska and NW Canada, the big backwards "S". 580+ close to even 590dm. These heights are something you see in the summer time near our latitude, must have been some record warmth up there at that time. Meanwhile at the surface a HP system 1064mb in Miles City, MT (lower 48 record) plunged the nation into single digits and below zero all the way down to the deep south for a long duration.
What set this event apart from others is the persistent of the -EPO. It popped and remained there for a long period of time. Notably Alaska experienced quite a mild month with very little snow or rain while the 48 plunged. McFarland's paper did not include this outbreak (because it was after the paper was written). However you can make the argument it was the granddaddy of all Mcfarland signature events.
To note 1983 was a neutral to weak La Nina year following the super El Nino of 1982. Another event that many don't know is that in 1982 El Chichon erupted in Mexico and had dramatic climate effects. It was rated VEI-5 a very major event that spewed massive amounts of sulfur dioxide. While smaller than Pinatubo the atmospheric response was just as large. 1983 went down overall as one of the coldest years (not just the december outbreak) on record for many sites.
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or 
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Always fun to do one of those for the arctic blasts!
