Boxing Night Snow/Sleet/Ice Dec 26-27 Storm Thread/Obs.

[Mikeymac5306]

 Safe to get this started as NAM is in range and 18Z GFS rolling.  Happy Tracking! 

[ChescoWx]

GFS likely continues to miss the warm nose at 700mb 

[ChescoWx]

1 minute ago, ChescoWx said:

GFS likely continues to miss the warm nose at 700mb 

 

[Kevin Reilly]

24 minutes ago, ChescoWx said:

GFS likely continues to miss the warm nose at 700mb 

So, 3-5" of sleet then freezing rain Let's Go!!

[MJO812]

Euro is great

[ChescoWx]

7 minutes ago, Kevin Reilly said:

So, 3-5" of sleet then freezing rain Let's Go!!

I kind of see it that way 3" to 5" of snow/sleet and then freezing rain....not a big fan of ZR!

[ChescoWx]

18z Euro trended much worse with more ZR less snow and less IP....this would be a not great solution!

[ChescoWx]

4 minutes ago, MJO812 said:

Euro is great

for Brooklyn yes....for the focus of this forum....not so much!

[MJO812]

Just now, ChescoWx said:

for Brooklyn yes....for the focus of this forum....not so much!

For NJ im talking about 

[Duca892]

Bleh looks more and more like a slop storm. Legit hate these. All I can think of is “Man what if this was all snow”

[ChescoWx]

4 minutes ago, MJO812 said:

For NJ im talking about 

Only North Jersey would see significant snow b4 any change to IP or ZR - not the area of most of the posters here

[mattinpa]

Still time for the colder solutions. Even I dislike ice. Hope the block holds.

[penndotguy]

Welp hope this early storm thread is a jinx, and we miss this whole mess all I see is brief thump of snow right to IP/ZR not a fan of either. 

[ChescoWx]

In my humble view I suspect what the RRFS (soon to replace the NAM) is showing is what may happen. A solid 2" to 5" of Snow/IP and then ZR on top. 

The below is through 1am Saturday just as the change to ZR is occuring to the NE of Chester County. Almost 2" of sleet at KMQS as part of their 4" Snow/IP total.

 

[Birds~69]

Adam Joseph 6abc around 6pm on Facebook a couple hours ago: 

POST CHRISTMAS STORM

First off, thankfully Christmas Eve & Christmas Day will be quiet! Santa will have some strong winds helping him make the rounds, and only a few sprinkles are expected near lunch on Christmas Day. Highs both days in the middle 40s. 

Now, to Friday!!! A piece of the nasty storm in California will break off and head across the country setting its eyes on the Mid Atlantic for Friday afternoon and night. The issue will be a large area of Artic High pressure in southern Canada. This will send down very cold air from the surface to thousands of feet up. Cold air is dense and heavy so it will be locked in as the storm arrives. The issue then becomes warm air trying to move in in the upper atmosphere as the storm ramps up. Warm air is light and buoyant, so it wants to settle where the precip forms in the storm in this kind of setup. Precip cannot turn to snow after it forms if the air temp is above freezing, so this is crucial in a mixed storm. Depending on the column of air temps from the layer where precip begins, to the ground will supply either rain (above freezing at all levels), freezing rain (shallow cold at only at surface), sleet (deep cold layer under the precip formation zone), and snow (below freezing at all levels). Our area will see all this mess.....the question this far out is where those areas set up. I do not see much rain with this system right now....more snow, sleet, and freezing rain. Some areas will see over 3" of snow!

I will be off enjoying two days with my family and will be back to guide you through it all on Friday. Please tune it to Payton and Brittany for the latest. Just wanted to give you a heads up and my current thinking.  Right now, this is our thinking and it will be fined tuned the next two days. Please share this in case people are not watching or on social at this time:

TIMING: snow for all mid to late afternoon Friday
HEAVIEST: falls near dark Friday through Midnight
CHANGEOVER: Snow flips to ice in much of the area starting Friday evening. 
ALL SNOW: looks to be north of the PA Turnpike with less mixing with ice. 
AVOID TRAVELING: late Friday afternoon into Saturday morning.

[RedSky]

0z guidance all backed north northeast

[anthonyweather]

0z guidance all backed north northeast

Kinda a given. Warm nose always wins out

Real mess coming

[penndotguy]

I mean how realistic is this with the strong blocking? I haven’t looked at it yet unless the High is moving out quicker than previously modeled. 

[Mikeymac5306]

CMC has it a touch warmer as well. 

[Duca892]

Was hoping to wake up to a Christmas miracle but looks like we are headed towards a slop fest. Le sigh

[penndotguy]

43F cloudy and yup just looked and the blocking seems to be weaker so there's that let this thing move North to NE for all I care. The Idea of IP/ZR does nothing for me, Maybe its an off run who knows. 

[Ralph Wiggum]

41 minutes ago, penndotguy said:

I mean how realistic is this with the strong blocking? I haven’t looked at it yet unless the High is moving out quicker than previously modeled. 

Block not as strong and stays mainly east based rather than west based as once forecast.

[The Iceman]

06z models even warmer... thought it was too early to start a thread tbh at least down towards 95. Trending towards meh. Merry Christmas! 

[Kevin Reilly]

As I see it now my inkling is that the block is too far east and like most times over past few years the cold air is booted NE and outta of southeastern Pennsylvania.  I think our true potential down here in southeastern Pennsylvania is 1-3” of snow then flip to sleet / freezing rain.  This is kind of a repeat from yesterday just more energy and moisture to work with.  It’s clear favored areas are NE Pennsylvania as far south as Doylestown points east and northeast from there.  4-7” Doylestown points NE. 

I would go winter weather advisories southeastern Pennsylvania western New Jersey and winter storm watches northern Montgomery County Bucks County points NE. Subject to change but best guess right now. 

it would take a fairly strong block to keep the torch of airmass in the  central and western United States from advancing east bound. 

[mattinpa]

If the air temp is still forecast below freezing we will still have problems - just not all snow due to the mid levels.

[Birds~69]

Only need a 50  mile S shift or so to be in the good/better stuff. Or we could get completely shafted. Still time...