A powerful storm will dump heavy snow (12-18 inches) from Denver to Omaha over the next couple of days and then it will try to head towards the east coast this weekend. A blocking pattern in the upper atmosphere, however, will impede its advancement to the East, but the threat still cannot be written off for some snow or rain here in the Mid-Atlantic region in the Sunday/Sunday night time frame; especially, from Philly to DC to South Jersey. If the storm does indeed make it out of the Midwest, and is not actually “squeezed” way to our south, then the odds would favor snow over rain here as the air would likely be just cold enough for snow by the latter part of the weekend. The computer forecast models are all over the place with this particular system as we transition to a different overall weather pattern and this change is causing difficulty for them. For example, it is likely that the models are underestimating the low-level cold air that will be available for this system if it indeed heads our way. Looking ahead, there are even colder air masses likely to visit this region during the next week to 10 days. Stay tuned.