The image below is a radar reflectivity loop of an intense snow band that moved through the Louisville metro area mainly between Midnight and 1 AM EST early on January 13th. During this time, an inch of snowfall was officially observed at the Louisville International Airport (Bold White Circle Southwest of the I-65/Watterson Junction). Since the bulk of the snow fell in about a half an hour, snowfall rates were estimated at close to 2 inches per hour! At the time of the snow, area webcams showed the Watterson Expressway quickly accumulating a coating of snow, along with near zero visibilities.
Dark green and even a few yellow pixels indicate heavy snow. Visibilities at the airport dropped to around a half mile for about 15 minutes, a threshold that can shut down airport operations if exceeded. An interesting observation is to note how wide this particular snow band was. The diameter of the white circle surrounding the airport is 2 mi and when compared to the snowband is about equal. This shows just how "hit or miss" accumulations of snow can be in a showery environment, and why caution should be used while driving. In this situation, conditions rapidly deteriorated over a short distance with blowing snow, reduced visibility, and roadways becoming slick.
The following images are from the Trimarc webcam located on the Watterson Expressway near the airport during the same period, with the first starting before the heavy snow fell, around 1130 PM EST and the last after that band headed east, at 1 AM EST. Click on any image to make it larger.
|11:30 PM EST 1/12/2012||Midnight EST 1/13/2012||12:40 AM EST 1/13/2012||1:00 AM EST 1/13/2012|