December 14 to 16, 2007 Appalachian Cold Air Damming Event
The first image shows that the core of a cold high pressure system is located in the western and central Great Lakes. The system moves east into northern New England by the third image and expands south into Virginia, North Carolina, South Carolina, and Georgia.
The observation at Charlotte, NC is located along the central border of North Carolina and South Carolina. Note how Charlotte's temperature falls as the shape of the ridge becomes more defined. Some of the initial drop is likely due to nighttime between the first and second image, but then the temperature continues to fall during the subsequent daytime. Also note the strong coastal warm front that develops and further defines the shape of the high pressure ridge.
In the third and fourth images, temperatures are in the 30s in the piedmont and foothills, including Charlotte. Temperatures along and southeast of the coastal front are in the upper 50s to lower 70s. In the last image, a storm system moving east into the region cuts off the ridge. At this point the event is rapidly terminating.
Images from the National Centers for Environmental Information data archives.
0000 UTC December 15, 2007 (6 PM CST December 14, 2007)
1200 UTC December 15, 2007 (6 AM CST)
0000 UTC December 16, 2007 (6 PM CST December 15, 2007)
0600 UTC December 16, 2007 (Midnight CST)
1200 UTC December 16, 2007 (6 AM CST)