2-7

2-7
Snow moved in around 8am in WCT, 8:30 here - check
Sleet mixed in around 11am - check
Freezing rain took over around 1pm - checkish.
Rain took over at 4pm - check
Will it make it to 47 by 7pm?
Nope - Made it to 34 at 0z. 13 degrees less than what the Nam and GEM had, 11 degrees less than the RGEM and 10 degrees less than the SREF/Nam3k.  GFS had 36 and Euro 35. 
What didn't happen were the snow totals - it just didn't thump like many thought.


2-6  Looking for the following to happen.

Precip moves into W CT around 7-8am. Its snow.  Temp should be in the lower 20's.  A lot with this storm will depend on where we start with temps.
 Around 11 snow transitions to sleet starting from the coast moving north. 
Around noon sleet becomes freezing rain for the coast, then moving north.
Around 2pm its freezing rain in Newtown, and most areas north of the Merrit.

What happens next depends on the surface temps.  Modeling has temps at 6pm anywhere from 34 degrees to 47 degrees in Northern Fairfield County.  If the cold air leaves early, we could go to rain by 3pm.  If it hangs around, 34 may be too high until precip lightens up.  If things go right, the 7-8 rush hour should be ok in almost all the state, with snow just starting. Then the afternoon rush 4 onward should also be alright with plain rain.

 I like 1-3 inches south of I84 with 3-6 inches as you move further north in the state. This includes most of Westchester/NNE NJ.  Maybe a coating in NYC.  Sussex County maybe 4-6.  Rest of NNJ 2-4. 

Here is Uptons forecast.  I'm a little less snow and more ice than they are.

The variables again are:  how fast does the precip come in?  Is the column saturated when it does or does it snow aloft for hours first?  When does the cold air become dislodged at the surface?  Is the precip basically over by the time temps rise?  Light winds from the east won't do it - have to wait for strong southerlies. This is from 9am.

This is from 1pm

And this is the temp. 

Doesn't look right. Particularly if the wet bulb is 24

This is the snow map with Kuchera from pivotal

vs others

2-5

Started this one late, but have been watching.  Situation is marginal in the tri state.  Would like to see it colder to start.  This storm is a bit different than the last one, as winds will be starting from the north, to northeast, to east as the system approaches.  This will keep the colder air in inland sections longer than if they were southerly for 24 hours before like this past storm.

Track has been narrowed down to heading right over us.  This typically brings a mix, and the amount of snow depends on how long the temps cooperate.  Many times, the precip runs ahead of what is modeled, cools the column more, and results in front loaded snow, an hour or two of transition, then some drizzle.   This is what the 18z NAM 3k is showing.

The reason for the mix isn't surface temps, but temps aloft.  Follow the 0c line and see where the temp crosses it. Its not by much, but enough.  This looks more like sleet but Pivotal shows the ice.

And the snow ex sleet map from pivotal

Why focus on the 3k?  Its the most interesting.  All other models also have the idea of front end snow, mostly resulting in 2" for N Fairfield County and more as you go north.  Here is a sample:

GFS

Icon

CMC

There hasn't been much movement in tracks today either.  All LPs seem to pass between Pou and ISP.  So its a nice cluster.  Energy is ashore now.  0z run will have samples.  If there is a change, it will show up soon.