Wednesday: Significant Weekend Storm, Colder Solution Prevailing

Good morning. We have a lot to talk about today as I am getting some more clarity on what will be a major weekend winter storm for many Saturday into Sunday. After a few days of evaluating the weather pattern ahead of the storm and the updated model guidance, one thing is standing out to me, we can not fight the dense cold air that will be out ahead of this storm. Models are now catching on to this idea and are not eroding away that cold air as quickly as originally thought. Translation, there is a good chance we are in for a heavy interior snowfall, and a potential high impact snow/ice storm for areas I-95 NW Saturday into Sunday. I have updated my winter storm outlook index! Our pattern change is here folks.

Real quick, before we get there, we will have a light snowfall event on Friday morning for all areas in CNJ north...

Expect a general 1-2 inches for many but higher amounts (2-4) in the higher elevations of NW NJ and into New England with this. More of a nuisance but it could cause some travel headaches Friday morning. Snowfall rates should not be too heavy however. It is over by 10am Friday.

Now, this minor storm sets the stage for the bigger storm for the weekend. Remember how in my Monday post I went into detail how the cold air this minor storm drapes down will set up a natural boundary between warm and cold air for the weekend storm to ride along.

Well, the cold air will be very cold, very dense, and very impressive by Saturday morning...

Sub zero in northern New England with temps in low to mid 20s for I-95.

The approaching storm is going to have to run into this dense cold air and try to fight it off...

Here is where things have been changing over last 24 hours on the models and the more I look at it the more it makes sense to me. It is not easy to just wipe out cold air like this. What normally happens is the cold air is under modeled. This means that although the warm air may with aloft, the temps hold firmer at the surface. This means only one thing- snow to ice/freezing rain. That outcome now is looking more likely for folks along the I-95 NW.

The big trend to really show this has been at 18,000ft where the models now are suggesting the northern jet stream does not try to phase early with the southern jet stream. This phase would have aided in warmer air moving into the region. The fact that that may not happen as early now means the cold air has a better chance of putting up a fight. The animation below shows the trend away from the phase as seen by energy in Canada retreating...

I noticed this start yesterday and the trend has continue overnight. Major forecast implication if this stays true. 

So what does this mean for impacts?

A front end thump of heavy snow now look like it can happen for many on Saturday afternoon/evening..

This would mean a several inches could pile up quickly later on Saturday night for many areas seen in blue above.

Then the warm air aloft should start to influence this storm and a changeover to ice occurs by early Sunday morning...

This will be a mix of snow, sleet and freezing rain for areas in the pink and eventually could change to all freezing rain for some. With surface temps holding steady near freezing, we can see big ice issues with this for many.

There then are indications we see a changeover back to some snow at the end of the storm Sunday afternoon/night. This detail still remains unclear...

When it is all said and done here are my initial thoughts on what impacts may be. Remember this can change considering it is only Wednesday..

Stay tuned, I will likely have a video tonight around 7pm. Lets see if the colder trend verifies.