12/3 Snow/Sleet/Mix Bag of Everything Discussion/OBS

[Mikeymac5306]

We're inside 36 Hrs. Safe to say this is a light event for Philly Metro and slightly moderate the more North and West you go. 

[simbasad2]

3 hours ago, simbasad2 said:

Here are my thoughts regarding totals for the region for Tuesday. Keeping the heavier snow to the northwest with a sharp gradient as you approach I-95. I'm thinking I might shift this even farther northwest in future updates but we'll see

 

 

Reposting this here

[LVblizzard]

Ahhh the classic snow to rain event in Allentown while the Poconos get hammered. I’m just glad we’re getting something this early in the season.

[penndotguy]

7 hours ago, LVblizzard said:

Ahhh the classic snow to rain event in Allentown while the Poconos get hammered. I’m just glad we’re getting something this early in the season.

After reading Mt Hollys AFD last night it’s plausible that rain snow line pushes even further NW almost to I 80. Elevation is going to be key 1000’ and above out there should get a good pasting. Also mentioned the start time might be earlier that previously thought which give us Far NW Burbs a shot at 3-5, but going with 1-3 with a periods of heavy snow before the changeover.

[Duca892]

While not a memorable event I feel like Whitehall/Bethlehem should get its first 1-2in of the year 

[Hurricane Agnes]

Brave soul to start the thread! 

6z 3k NAM says "No snow for you" along the coastal plain.

[Mikeymac5306]

41 minutes ago, Hurricane Agnes said:

Brave soul to start the thread! 

6z 3k NAM says "No snow for you" along the coastal plain.

Of course, models will flip a 180 24 hrs. out lol!

[Mikeymac5306]

WWA hoisted for MBY

[JTA66]

Ah yes, the WWA...the kiss-your-sister of weather alerts. It's only 12/2, I'll take my handful of pity flakes tomorrow and tell myself it a harbinger of better things to come.

[Hurricane Agnes]

7z NBM for snow and ice.   Probably gonna be some crust on snow and/or ice coatings, depending on the air temps as the changeover happens further north.

[KamuSnow]

2 hours ago, Hurricane Agnes said:

Brave soul to start the thread! 

6z 3k NAM says "No snow for you" along the coastal plain.

I guess we've been reverse NAM'ed, lol. Based on that, if I see a dusting here I'll consider it a win, plus what JTA66 said.

[simbasad2]

I'm really disliking the overnight trends for I-95 and the immediate suburbs. 12z NBM has literally no snowfall for the entire urban corridor (Eastern Chester, Eastern Montgomery, Lower Bucks NWS forecast zones and points SE). This storm is reminding me of the one we had around this time in December 2019

[ChescoWx]

43 minutes ago, simbasad2 said:

I'm really disliking the overnight trends for I-95 and the immediate suburbs. 12z NBM has literally no snowfall for the entire urban corridor (Eastern Chester, Eastern Montgomery, Lower Bucks NWS forecast zones and points SE). This storm is reminding me of the one we had around this time in December 2019

 

I suspect even that 1" up at ABE may be a bit overdone if the latest models are onto something...850's a bit toasty 

[ChescoWx]

The HRRR tries to sneak the 2" line into NW Chesco and close to ABE....for snow weenies we present the snowiest latest models...

[Duca892]

annndddd this is starting to dwindle a bit as we come closer to game time lol

[Hurricane Agnes]

1 hour ago, simbasad2 said:

I'm really disliking the overnight trends for I-95 and the immediate suburbs. 12z NBM has literally no snowfall for the entire urban corridor (Eastern Chester, Eastern Montgomery, Lower Bucks NWS forecast zones and points SE). This storm is reminding me of the one we had around this time in December 2019

This setup in January or February would have had quite a few cashing in, with some possible overrunning closer to the coast.  But it's still early in the season and the water is "warm" (and the low is supposed to be coming out of the warm Gulf).  If the low moves further to the east, some of the colder air could mix in and bring the R/S line further east.

[Newman]

Yeah 12z models coming in warmer for those who were on the line NW of 95 up to I-78. I still think Berks, Lehigh, Northampton can squeeze out 1-3 inches on the initial thump IF it starts as snow. However, if there's a pesky warm nose (i.e. that some of the warmer guidance shows) things could start as sleet which would cut down entirely on snow totals. It's not really a sleet type of storm, though I'm talking about the initial thump before the true warm surge happens as the low tracks to the S and SE of the area off the coast.

[Birds~69]

2 hours ago, simbasad2 said:

I'm really disliking the overnight trends for I-95 and the immediate suburbs. 12z NBM has literally no snowfall for the entire urban corridor (Eastern Chester, Eastern Montgomery, Lower Bucks NWS forecast zones and points SE). This storm is reminding me of the one we had around this time in December 2019

You can only name one? This storm reminds me of every storm...

[penndotguy]

Well at least we are all used to this by now, shouldn’t really surprise anyone. By tonight it’ll show rain in Poconos. How do they say…wash,rinse, repeat

[penndotguy]

Storm threads shouldn’t be started till the day before at the earliest. I enjoyed my coating yesterday, I’m ready for a cold Rainer here in Western Berks

[Newman]

Not the trend you want to see up to storm onset. 925s and 850s are just too warm, which makes sense given the setup. Hopefully this trend halts and we see things shift SE tonight. But at that point, it's time to look at obs and radar watch. Shaping up to be a typical early season interior storm with maybe a surprise 1-2" thump on the southern boundary along I-78

[RedSky]

GFS has become Dr No and the ECM is now the old GFS what a world we live in

 

[zenmsav6810]

Lol. My forecast is a "wet dusting". I must say social media is over run with a plethora of "weather authority" vendors these days- and most of them are posting absolute slop these days. Any body with a computer and a map is pushing out snow maps today! I'm sure AI isnt helping with that either.

 

[RedSky]

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
111 PM EST Mon Dec 1 2025

NJZ009-PAZ101-103-105-020900-
/O.CON.KPHI.WW.Y.0013.251202T0900Z-251202T1500Z/
Hunterdon-Western Chester-Western Montgomery-Upper Bucks-
Including the cities of Perkasie, Collegeville, Pottstown, Honey
Brook, Flemington, Oxford, and Chalfont
111 PM EST Mon Dec 1 2025

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 4 AM TO 10 AM EST
TUESDAY...

* WHAT...Mixed precipitation expected. Total snow and sleet
  accumulations up to one inch and ice accumulations around a light
  glaze.

* WHERE...In New Jersey, Hunterdon County. In Pennsylvania, Upper
  Bucks, Western Chester, and Western Montgomery Counties.

* WHEN...From 4 AM to 10 AM EST Tuesday.

[LVblizzard]

Monumental failure by the Euro with this storm. DT is probably questioning his entire existence after this.

[simbasad2]

Final call for this storm, shifting everything to the north and west by a ton. The storm keeps trending slower and slower AND warmer, both horrible for our storm for everyone. I'm thinking I-95 will start as a wintery mix and areas just NW of 95 will start as some flakes before quickly shifting over. Far NW suburbs + mountains will still likely see some decent accumulations, but I removed the 6-8 contour for the poconos as totals downtrend even for up there. Schuylkill, Carbon, and Monroe counties are the only areas on this map that will remain all snow. Still can't rule out isolated 6"+ for those areas but not widespread enough to add the 6-8 contour back

[Newman]

GFS at 18z remains colder than any of the mesos for the I-78 corridor and even ends as snow around 2pm tomorrow. It's probably not picking up on the warm punch, but given the soundings are all basically 33-degrees and isothermal, maybe the models are underestimating the cold tonight? Will just have to see what happens, NWS forecast looks great to me based on current guidance.

[Newman]

3k actually never gets KABE above freezing at 850s (though it's close), but does sneak to 33 at 925 down to the surface. At 1-2pm tomorrow, the 3k shows rain BUT some deep lift just below the DGZ and even stretching into the DGZ. The DGZ is pretty high up in the atmosphere, but as you can see in the skew-T the sounding is marginally above freezing. If you can get some deep lift and rates to increase within a backside band as the storm departs, you could potentially finish with some heavy snow and fat dendrites if the column cools isothermally back to freezing. Of course, all of this could be for nothing and if 1.) The mesos are correctly handling temperatures and 2.) The rates aren't heavy enough to cool the column then we'll definitely see the lower end of snow totals materialize. Just wanted to point out a way that you could potentially see higher end (3-4" totals) materialize along the I-78 corridor which is currently the 90 percentile from the NWS.

[zenmsav6810]

I think there is cold air around- something I saw a day or two ago showed the polar vortex as very fragmentary air mass right now. It makes me wonder if there is more cold air aloft than the models (especially the Mezos are accounting for). I was also impressed with the snow we got on Sunday despite the warm ground level temperatures. 

[JTA66]

Dipped below freezing, currently 31F with a DP of 20F.

Bar set at 15-20 minutes of pity flakes.