By Joseph D’Aleo, CCM

After the recent snow events, the northern hemisphere snowcover has risen above the 10 year climatology as can be seen from the following charts courtesy of Dr. Bob Hart at Florida State University. They are updated as of December 17, 2007.

Chart shows the current snowcover compared to the 10 year climatology for the date (green line).

The graph showing percent of Northern Hemispheric snowcover compared to normal and the daily anomaly (red deficit, blue surplus)

Note the deficits in much of the fall gave way to surplus the last week. Expect this to oscillate as storms depending on exact tracks, melt snow and erode edges or lay down a new swarth of snow.

Snow is important in maintaining and enhancing cold air masses in winter. I believe we will see its effect in January as some of arctic high pressure building across the high latitude snowfields in North America and Siberia makes its way into the states.  January will be colder than normal in many areas the NOAA and private forecasters are promising January warmth. See update with full size images here.