Thursday, March 13, 2014

A Normal Winter?



The National Climatic Data Center (NCDC) released its analysis of the past winter today and the assessment for South Carolina? Near normal. The statewide average turned out to be the 66th coldest and 65th wettest winter on record.  The ranking was based on 120 years of data.


The statewide rank of temperatures (top) and precipitation (bottom) based on 120 years of records (since 1895).  A rank of 1 for temperature would be the coldest while for precipitation it would be the driest.  Click on the image for a larger view. Image credit: NOAA/NCDC.

Don’t let the averages fool you.  This was anything but a normal winter.  The average does not do justice to the character of the winter we just experienced.  The weather pattern for much of this area has been one of one extreme to another and this has been the pattern since late October.

The monthly temperature anomalies for December 2013, January 2014, & February 2014.  The anomalies use the 20th century average for the base figure.  Winter averaged near normal, but the were significant month to month differences.  Click on the image for a larger view.  Image credit: NOAA/NCDC.

We also had the worst winter storm in at least a decade with more damage to the forest than since Hurricane Hugo in 1989.  The storm produced twice the number of power outages than occurred with the 2004 winter storm.

This was the 34th coldest winter on record for the U.S. in the past 120 years.  Here again there were significant differences.  It was the coldest winter in recent memory for parts of the Midwest, but the warmest winter on record for California.  There were significant snowstorms, but it was the driest winter on record for southern California.


The divisional rankings for the winter of 2013-2014.  The key in the first group of maps applies to these.  A rank of 1 for temperature would be the coldest while for precipitation it would be the driest.  Click on the image for a larger view. Image credit: NOAA/NCDC.

It is significant that it turned out to be the coldest winter since 1979 for the Upper Midwest.  This led to greater ice cover on the Great Lakes.  According to the National Oceanic and Atmospheric Administration (NOAA) Great Lakes Environmental Research Laboratory (GLERL), ice cover on North America’s Great Lakes peaked at 88.42% on Feb. 12-13 – a percentage not recorded since 1994. The ice extent has surpassed 80% just five times in four decades. The average maximum ice extent since 1973 is just over 50%.

A time series for average winter temperatures in the Upper Midwest 1895-2013.  Click on the image for a larger view.  Image Credit: NOAA/NCDC.
This false-color image uses a combination of shortwave infrared, near infrared and red (MODIS bands 7,2,1) to help distinguish ice from snow, water and clouds. Open, unfrozen water appears inky blue-black. Ice is pale blue, with thicker ice appearing brighter and thin, melting ice appearing a darker true-blue. Snow appears blue-green. Clouds are white to blue-green, with the colder or icy clouds appearing blue-green to blue.  The image was captured on February 19, 2014.  Click on the image for a larger view.  Image Credit: NASA.

So, what can we say about this past winter?  Goodbye and good riddance.  It will take some time for the Upper Midwest to thaw.  The rainy season, what little there was, is coming to an end for California and it will be a hot, dry summer.
    
For South Carolina there is the prospect for a late freeze due to the current weather pattern.  It would be prudent to wait until mid-April before planting any tender plants.  However, the outlook calls for a quick warm-up during the spring and a hot summer ahead.  Winter may be a fading memory soon.  People will be asking “when is it going to cool off?” once we get to the heat of summer.