A unique and somewhat problematic weather pattern has set up across the United States and will remain for some time. This pattern will provide very cold temperatures for the eastern two-thirds of the lower 48 while average to slightly above average temperatures will prevail for the west. An example of these cold temperatures can be found at Amarillo, TX where the daytime high of 14 degrees Fahrenheit was 37 degrees below the daily average. Also, stormy weather will prevail at times across the Midwest and East Coast.
The upper level pattern over the United States is blocked providing for a large and energetic trough across the east with a docile ridge for the west. This blocking pattern will last for at least the next week and a half. At the same time, the flow in the upper level pattern is very progressive and will allow for the genesis of weather systems and their quick movement over the eastern U.S.
The recent storm development over the East Coast has been a product of this large-scale upper level pattern. The low pressure development forecast for late Thursday and into Friday is the next of a string of snow-makers. It is no surprise that current storm forecasts are very uncertain as weather forecast models struggle with this type of pattern.
Low pressure moving northeast across the Appalachian Mountains will help to develop another low pressure area south of Long Island, NY and the new low will move northeast out to sea. Where will this secondary low track? This question obviously cannot be answered immediately judging from the uncertainty of forecast models. However, it is safe to say that at least some snow will fall in southern New England and the Mid-Atlantic Coastline.