It's enough of a problem for computer modeling to figure out what's going to fall and where over the next couple of days. So, why not talk about something six days out? Well, because it may usher in the coldest shot of air so far this winter.
It's not saying much because temperatures this winter have not dipped below 25 at the Airport but a rather chilly time of things looms starting Sunday night.
Sunday could be pretty mild -- in fact, it could hit 50 by midday. However, the low pressure center and its associated cold front will pass through the region and will help usher in a colder airmass for the second half of the three day weekend.
Those blue and purple lines on the map above are the temperatures at 5000' up in Celsius -- that's subzero air aloft looming over Michigan and the Great Lakes where it's below -20 C. That air doesn't quite make it here in the wake of this shot although the -12 and colder will -- that's supportive of lows around 20 in Philadelphia on Monday morning if the cold materialized as the European model hypes it to be.
Even if we assume a slight "improvement" as the cold shots modeled out a week have not been as strong as we approach reality, we're still looking at mid 20's on Monday morning, perhaps the coldest of the winter so far if we can break 25. Colder air may be in the offing for the middle of next week as lows look to get into the teens a week from Wednesday.