An extremely complicated forecast is coming up as we move into late this week. The first Thursday and Friday of 2014 might be days to remember.
First, what I know: Your New Year's Eve plans and New Year's Day will be storm-free. Temperatures by midnight as the ball drops and fireworks explode will be in the mid-20s.
New Year's Day for the Mummers taking out possibility of snow flurries (as they should pass well north of Philly) and temperatures in the 30s.
After that, however, ALL bets are off.
A bundle of upper energy will be diving southeast representing the leading edge of some of the coldest temperatures to invade the Northeast in almost 20 years.
Speaking in meteorological terms, it's called a Miller Type B Storm, which involves two storms, one weakens as a secondary coastal storm rapidly intensifies. Some of the biggest storms in the Northeast have taken place with Miller B storms.
For example, the blizzard of Jan. 6-8, 1996 was one of the most paralyzing blizzards of all-time. (Officially 30.7 inches fell in Philly.)
This is not going to happen with this one, but I'm just pointing out these type of storms are capable of rapid intensification and a lot of snow.
They are also the most difficult ones to forecast as computer models. This far out (more than 72 hours) we have extreme difficulty in pinpointing exact secondary location, how much intensification, track and weather elements.
Still, a widespread case scenario on various models, ensemble models on GFS, and Euro are both indicating coastal storm intensification somewhere around the Lower Chesapeake by Thursday evening and then tracking northeast off the coast into a very intense storm off the New England coast by Friday afternoon.
What happens between Thursday late and Friday morning here in Philly is still highly speculative.
Blending the latest computer models, this is the early case scenario:
Storm formation somewhere around the Virginia coast by Thursday evening, and then tracking east-northeast as these types of storms usually track more easterly than northerly.
This should mean more frozen precipitation than liquid, however with that being said, if the storm is far enough off coast it would keep the bullseye of heaviest precipitation east of I-95 corridor and off the coast. That would mean snow for most, but spare us any type of major snow amounts.
Also these types of storms have produced snow to rain and then changing back to snow as frigid air wraps in and snow ratios go up.
With all this being said, the one thing I definitely know at this time is on Friday some of the coldest air in some 20 years will strike the entire Northeast, with many locations to our north and west going down below zero come Friday night and wind chills of 20-30 below zero.
Philly will see temperatures by day on Friday struggling through the teens and wind chill factors below zero.
Code blue status will be issued for late Thursday night into Saturday.
A reminder: Pets feel the cold as well, so bring all pets indoors on Friday and allow for only brief walks.
To even guess at the snow amounts at this time would be ludicrous, as we could see hardly anything to a whole lot.
As we get closer to a potential storm event, I will start to break down your counts. To do so now would be a waste of time, as honestly we simply don't know yet.
Right now I'm rating this a moderate storm potential - meaning slightly better than a 50 percent chance we see accumulating snow late Thursday into Friday morning.