Sunday, January 5, 2014

Arctic Cold? I'll take a Double!

The new year is taking up where the old year ended.  The weather pattern discussed in a previous post continues to dominate North America.  Each time the pattern amplifies with a strong ridge-trough-ridge look, cold air invades the U.S.  The pattern relaxes and becomes more zonal causing milder conditions to return.  This is the up and down pattern that has resulted in a roller coaster of temperatures.

This was the 500 mb pattern for North America at 12z December 9, 2013.  Note the ridge-trough-ridge pattern.  Click on the image for a larger view.  Image Credit: WSI.

This was the 500 mb pattern for North America at 00z January 6, 2014 (taken from the ECMWF model 12 hours earlier.  Note the ridge-trough-ridge pattern returns.  Click on the image for a larger view.  Image Credit: WSI.

However, this time there has been a bit of a twist.  A surge of cold, arctic air invaded much of the country at the end of last week.  The temperature in Columbia dropped to 22° F Saturday morning.  The high pressure center moved quickly to the east causing winds to shift bringing clouds back into the area before daybreak.  This locked in the cold air for the weekend and there wasn’t much of a rebound in temperatures.

This surge of arctic air was the coldest of the season with temperatures down to -50° F at Key Lake in central Canada.  Even International Falls, MN, dropped to -43° F on January 2nd.  The bulk of this cold moved east across the Great Lakes and into the Northeast.  Caribou, ME, dropped to -28° F on the same day.

The latest surge of arctic air is not quite as cold at its core, but does have higher winds.  This is leading to some dramatic wind chills across the country with warnings for wind chills and extreme cold stretching from the Canadian border to the Gulf coast.

Various warnings and advisories for the U.S. late on Sunday, January 5, 2014.  Click on the image for a larger view.  The legend is separate from the map.  Image Credit: NOAA.

A strong cold front will pass through South Carolina Monday morning.  Many areas will see the high temperature for the day around daybreak.  Winds will be gusting to 40-45 mph behind the front and temperatures will be falling throughout the day.  The winds will diminish some Monday night, but the cold air will continue to rush into the area.  Temperatures across central South Carolina will be in the range of 10° F in the northwest to 18° F in the southeast by daybreak on Tuesday.  Columbia should have a temperature of 15° F, but winds will still be sustained at about 10 mph.  This should lead to wind chills in the range of 0° F to 5° F.  There is a good chance of setting the low temperature record for the date which is 16° F.

The center of high pressure will be over the region Wednesday morning.  This is likely to result in similar temperatures without the wind chills.  Calm conditions are expected for Wednesday morning.

This will be the first time Columbia has been below 20°F since January 4, 2012.  It will be this first time we have seen a double dose of arctic air since December, 2010, when it dropped to 16°F on the 8th and dropped to 15° F on the 15th.  This was also the last time it was this cold.  You have to go back to January 17, 2009, to find a colder temperature in Columbia where it dropped to 13° F.

Be prepared for the cold, but don’t let it get you down.  Temperatures will rebound quickly after Wednesday and it will be much warmer by the weekend.  However, this will not be the last cold surge for the winter.  A January thaw is expected through the middle of the month.  This is expected to be followed by more arctic cold at toward the end of the month.

Stay warm!