December Cold Pattern Set Up

Written by on November 28, 2013 in NatGasWeather - No comments

The Arctic Outbreak we have been advertising for the first week of December is still on track.  Here is the latest on how it will unfold.

 

The first weather map shows where the major players are located on December 1st.  There is still a fairly broad trough of low pressure over the eastern US with a weak clipper tracking across the Midwest into New England, providing a light dusting of snow (note the yellow and green colors which show spin in the

Wednesday Night Low Temperatures

Wednesday Night Low Temperatures

atmosphere).  More importantly, a deep low pressure system associated with very cold air will be dropping into southwestern Canada.  This is the beginnings of a big pattern change for the western US and will lead to a subsequent gradual march of bitter cold air across the entire US next week.  It will take several days for the cold to filter through the Great Basin before reaching the Plains by mid week.    The second image shows where conditions are likely to be much colder or warmer than normal on December 5th.   The west is expected to have temperature anomalies of greater than 20°F, while the east warms up from the recent cold, easing national demand.

 

It is clear, most of the western half of the US will be under the deep freeze.  What is not clear is how fast the cold air will sweep across the central US and into the east and also how far into the South the bitter cold makes it.   Both are expected to happen eventually.   Once the cold air does get established over the central and eastern US late next week, it looks to remain as reinforcing shots of cold air should keep the cold pattern in place through mid December. The third image shows how the pattern favors additional cold  outbreaks being forced toward southern Canada around December 10th and into the US shortly after.

 

The upper level weather pattern on December 1st.  A weak clipper across the Midwest and a deep low and cold pool setting up over southwest Canada.

The upper level weather pattern on December 1st. A weak clipper across the Midwest and a deep low and cold pool setting up over southwest Canada.

 

 

By December 5th, the deep cold pool will have pushed into the Plains and taking aim at the central and eastern US.

By December 5th, the deep cold pool will have pushed into the Plains and taking aim at the central and eastern US.

Around December 10th, after cold air has become established over much of the US, a reinforcing shot of bitter cold will be dropping south through Canada and taking aim at the US.

Around December 10th, after cold air has become established over much of the US, a reinforcing shot of bitter cold will be dropping south through Canada and taking aim at the US.

Leave a Comment