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.

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

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

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

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

GFS likely continues to miss the warm nose at 700mb

NAM 12km has the start of the sleetfest after a couple inches of snow - verbatim could be 2" to 4" of snow/sleet before any change to ZR....but alas that will change a lot by Friday!

Sleet fest which is better than ZR for sure!

We ended up with 1.0" of snow here in East Nantmeal this morning. This was our 5th winter event of the young winter season. The 10.4" of snow recorded this month here in EN is the snowiest December since the 11.7" of snow back in 2017. This is the 6th snowiest December in the 23 years I have been at this location. We get a brief reprieve from the winter weather through Christmas Day with afternoon temperatures just a few degrees below normal for the big day. Our next winter event looks like it could be our most impactful so far this season. Snow should arrive around noon on Friday we should then see a change to first sleet and finally freezing rain as we move through the afternoon. Temperatures during the storm on Boxing Day are likely to only warm into the upper 20's to near 30 degrees so what falls will likely be frozen in some form. We warm to near normal on Sunday before we turn much colder again on Monday and look to see below normal temperatures through the remainder of 2025 and into the first week of 2026.

We ended up with 1.0" of snow here in East Nantmeal this morning. This was our 5th winter event of the young winter season. The 10.4" of snow recorded this month here in EN is the snowiest December since the 11.7" of snow back in 2017. This is the 6th snowiest December in the 23 years I have been at this location. We get a brief reprieve from the winter weather through Christmas Day with afternoon temperatures just a few degrees below normal for the big day. Our next winter event looks like it could be our most impactful so far this season. Snow should arrive around noon on Friday we should then see a change to first sleet and finally freezing rain as we move through the afternoon. Temperatures during the storm on Boxing Day are likely to only warm into the upper 20's to near 30 degrees so what falls will likely be frozen in some form. We warm to near normal on Sunday before we turn much colder again on Monday and look to see below normal temperatures through the remainder of 2025 and into the first week of 2026.

Still snowing steadily here in East Nantmeal temperature is 31.4 and as of 7am we have 0.8" of snow. All surfaces covered.

Still snowing steadily here in East Nantmeal temperature is 31.4 and as of 7am we have 0.8" of snow. All surfaces covered.

As we talked about earlier the forecasts have changed significantly for Friday - per the latest AFD The updated forecast now has highs on Friday in the mid to upper 30s for the I- 95 corridor and west with mid to upper 20s in the Poconos. Areas south and east of the I-95 corridor have highs in the low to mid 40s. Wintry precipitation is now the result for much of the area for at least part of the timeframe from daybreak Friday into Saturday. Mixed precipitation may make it as far south as parts of Delmarva. Warm air looks to gradually filter in through this event which would cause a changeover to rain. Right now, the best potential for this to be a mainly rain event looks to be in parts of Delmarva and southern New Jersey. There is a large amount of uncertainty with the forecast for Friday into Saturday and trends will need to be monitored. Uncertainty remains through the weekend but there are indications that the forecast stays unsettled.

From Meteorologist Bobby Martrich on these huge changes to Friday "Last 4 runs of the GFS are comical... and it's not alone with this idea of a colder day Friday - just after Christmas. Much colder in fact, so instead of 50s you cut 25° off the high temps and get frozen precip, not rain. This goes back to the prior video discussions where I talked about models struggling in seasonal transition and being overzealous about the supposed "torch" pattern. If you're on the colder side of that thermal gradient, it's a much different outcome. This is the result of models completely whiffing on the extent of blocking in the Northern Atlantic and Atlantic Canada and a much stronger Quebec high providing the cold air damming. While we need to see this apparent trend to continue to alter the forecast, the Friday forecast could look much different if it does."

How's that high in the 50's you bet on for Christmas Day looking? LOL!!

The latest European for Friday.....a wee bit different from prior model runs.

Below normal temperatures look to continue through at least Christmas with some models now hinting at significantly colder weather than currently forecast for Friday. We do have a chance of some light snow, sleet and freezing rain arriving tomorrow morning. While amounts will be light the timing near rush hour could be a potential problem. We should dry out by tomorrow afternoon. Christmas Eve Day looks sunny. Plenty of uncertainty regarding both temperatures and precipitation by Christmas Day and Boxing Day.

Below normal temperatures look to continue through at least Christmas with some models now hinting at significantly colder weather than currently forecast for Friday. We do have a chance of some light snow, sleet and freezing rain arriving tomorrow morning. While amounts will be light the timing near rush hour could be a potential problem. We should dry out by tomorrow afternoon. Christmas Eve Day looks sunny. Plenty of uncertainty regarding both temperatures and precipitation by Christmas Day and Boxing Day.

I suspect that high near 57 on Friday will be coming down significantly later today...

06z GFS

This may be the largest temperature swing over 1 run I have ever seen on a model. The other models have similar cold trends.

Below are my obs from Thorndale in December 1998 and from the Coatesville 2W NWS observer. Not too much snow but just enough for the White Christmas

Happy first day of Winter to those that celebrate! We are at about our high temperatures for today with a cold front passing through this morning. Today’s temperatures will drop to freezing by evening. Below normal temperatures tomorrow with near normal high temperatures through Christmas Day. The warmest day of Christmas week looks to be on Boxing Day with temperatures well into the 40's and maybe even 50 in some valley locations. We turn chilly again on Saturday. It looks increasingly likely that snow will arrive by Tuesday morning's rush hour. We should see less than an inch of snow before any change to rain for most of the area with more up toward the Lehigh Valley. Additional rain shower chances for both Christmas and Friday.

Happy first day of Winter to those that celebrate! We are at about our high temperatures for today with a cold front passing through this morning. Today’s temperatures will drop to freezing by evening. Below normal temperatures tomorrow with near normal high temperatures through Christmas Day. The warmest day of Christmas week looks to be on Boxing Day with temperatures well into the 40's and maybe even 50 in some valley locations. We turn chilly again on Saturday. It looks increasingly likely that snow will arrive by Tuesday morning's rush hour. We should see less than an inch of snow before any change to rain for most of the area with more up toward the Lehigh Valley. Additional rain shower chances for both Christmas and Friday.