Good Afternoon Everyone,
Its been a while since I had a chance to do some blogging, but finally back here again. This product looks to come out just a few weeks after the month concludes. So, let’s take a look at December of 2011.
The first image shows what happen globally with regard to weather hazards. If you click on the image below, you will able to see it much larger.
Next, let’s take a look at the Significant Events for the month of December. If you click on the image below, you will able to view the full report for this month.
Next, let’s examine the 500mb Height and Anomaly map. When you look at the 500mb map, you can get a sense where ridges and troughs setup. The shades of red indicate ridging, while the shades of blue indicate troughing.
Let’s compare December of this year to last year. Notice how much ridging extended over the Pacifc Northwest southeastward toward the East Coast. All the shades of blue, which indicate troughing was up over Canada and Greenland. Click on the image to see December of 2010. What you’ll notice is that the upper air flipped, where ridging took up shop over Greenland.. No doubt, this year is a different story, where blocking just hasn’t developed.
Next, let’s take a look from last year as we went from December to January of this past year. 
As you can see, it was a favorable pattern for colder and snowier pattern over the Eastern portions of the Middle Atlantic and Northeast US. One of the themes to note on these analyses was how much ridging took place over Greenland. At this time the NAO and AO were negative, which is very critical for a cold and snowy pattern. So far this current winter season, we have not seen that happen. These are just some of the themes I’m noting for folks over the Eastern US. If you go back to last year, there were two major winter storms, December 26-The Boxing Day Storm, and January 26th. So, all the ingredients to get the big winter storms were very favorable. No doubt, this winter has been not so favorable.
To access this data and more, head over to National Climate Data Center.