Modeling had waffled a fair amount regarding the details of this weekend's cold frontal passage -- varying in timing between Saturday and Sunday between the GFS and Euro. Last night's modeling seems to have come to some sort of consensus...one that may be short lived but seems to focus on Sunday and Sunday night as the period of bad weather.
The nice weather (more discussion on "how nice" it will be is forthcoming this evening) that we've experienced over the past several weeks (seemingly) comes to an end as a strong storm system organizes in the Plains around midweek and slowly pushes northeast into Canada. While the low in Canada will be rather strong, it will be far, far to our north and leave us with a frontal passage of rain and thunder for Sunday night and perhaps early Monday.
The possible tropical influence is still on the map, with both the Euro and GFS showing an area of low pressure and tropical moisture pulling north through the Gulf of Mexico towards the front this weekend. This influence of moisture may work up the front and impact us by enhancing the rains that the front brings to the mix.
More important, some of the modeling tries to cut off the remnant surface feature on the tail end of the front over the Southeastern US early next week, then moving the surface low up I-95 with more rain in the Monday, Tuesday, and Wednesday time frame. This isn't a consistent development and not something that the models are handling very well but it has shown up a couple of times over the last 24 hours. I think we'll probably see a bit more waffling and change over how this tropical moisture and surface low interact with the front in the coming days. At minimum, it does look like for now one can focus on Sunday as the lesser weather day of the two...operative words being "for now" as we could see a bit more evolution in this before the weekend.