Central PA Winter 25/26 Discussion and Obs

[TimB]

1 hour ago, ChescoWx said:

Today will be near to slightly above normal with highs in the middle 40's. We warm a bit more tomorrow into the upper 40's and then the low 50's by Friday. Rain arrives by Thursday night and would expect to see some areas of fog as the snow melt ramps up tomorrow night. We could see 3/4 to an inch of rain. We then turn colder again for the weekend and into the start of Christmas week.

And then what happens later in Christmas week? Any shot at a white Christmas in Chester County?

[Itstrainingtime]

Today's 12z Canadian run has snow moving in late Christmas evening through the first half of the day on the 26th in eastern PA. 

[canderson]

50 at 4 pm. 

[mahantango#1]

NWS says possible freezing fog tonight after 2-3am.

[Itstrainingtime]

2 minutes ago, mahantango#1 said:

NWS says possible freezing fog tonight after 2-3am.

Freezing fog tonight, thunderstorms in the forecast for tomorrow night. 

[mahantango#1]

10 minutes ago, Itstrainingtime said:

Freezing fog tonight, thunderstorms in the forecast for tomorrow night. 

It would be nice to experience a good thunderstorm this time of year. There is also a myth to having a thunderstorm in winter. Something like within 10 days of a thunderstorm in winter there will be a snowstorm.

[ChescoWx]

7 hours ago, TimB said:

And then what happens later in Christmas week? Any shot at a white Christmas in Chester County?

Poor Timmy where is that 50 plus degrees you were preaching about for Christmas Day earlier this week? LOL

[Blizzard of 93]

7 hours ago, Itstrainingtime said:

Today's 12z Canadian run has snow moving in late Christmas evening through the first half of the day on the 26th in eastern PA. 

The Canadian looks a lot like the 6z GFS from earlier today with a chance of a little snow to icy mix for many of us.

[Blizzard of 93]

1 minute ago, Blizzard of 93 said:

The Canadian looks a lot like the 6z GFS from earlier today with a chance of a little snow to icy mix for many of us.

The Euro has a similar look but is displaced a little further north & east with mostly rain for CTP around Christmas.

The GFS has been bouncing around today.

The general idea of a wave tracking near us is there sometime around Christmas Day, but the details need resolved as the week goes on. Hopefully we end up on the right side of the boundary to get a couple of inches of snow to a mix if we get the right track & the cold in the northeast can hold in enough east of the mountains.

[Blizzard of 93]

It is truly remarkable that MDT is running 9 degrees below normal temperature for the month through 12/16.

What a cold stretch, along with above normal snow for the season to date at 4.7 inches.

Great start to the season & hopefully we are on our way to a good Winter that is overdue for many of us.

[canderson]

Wind threats are a big things Friday. Possible even 60 mph winds for some of us.  

[mahantango#1]

URGENT - WEATHER MESSAGE
National Weather Service State College PA
147 AM EST Thu Dec 18 2025

PAZ004>006-010>012-017>019-026>028-035>037-041-042-045-046-049>053-
056>059-063>066-190915-
/O.NEW.KCTP.WI.Y.0016.251219T0600Z-251220T0600Z/
Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield-
Northern Centre-Southern Centre-Huntingdon-Mifflin-Juniata-Fulton-
Franklin-Tioga-Northern Lycoming-Sullivan-Southern Clinton-
Southern Lycoming-Union-Snyder-Montour-Northumberland-Columbia-
Perry-Dauphin-Schuylkill-Lebanon-Cumberland-Adams-York-Lancaster-
Including the cities of Selinsgrove, Ridgway, Lewisburg,
Coudersport, Wellsboro, Mount Union, Renovo, St. Marys,
Huntingdon, Trout Run, DuBois, Harrisburg, York, Mansfield,
McConnellsburg, Mifflintown, Williamsport, Berwick, Lebanon,
Emporium, Gettysburg, Hershey, Sunbury, Pottsville, Clearfield,
Philipsburg, Chambersburg, Lock Haven, Warren, Newport, Danville,
Bloomsburg, Shamokin, Lancaster, Bradford, Carlisle, Laporte,
Lewistown, and State College
147 AM EST Thu Dec 18 2025

...WIND ADVISORY IN EFFECT FROM 1 AM FRIDAY TO 1 AM EST SATURDAY...

* WHAT...West winds 15 to 25 mph with gusts up to 50 mph expected.

* WHERE...Central Pennsylvania.

* WHEN...From 1 AM Friday to 1 AM EST Saturday.

* IMPACTS...Gusty winds will blow around unsecured objects including
  holiday decorations. Tree limbs could be blown down and a few
  power outages may result.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high
profile vehicle. Secure outdoor objects.

[pawatch]

17 degrees this morning. No fog this morning, but I think all the road salt on the roads helped the black ice situation some.

[Blizzard of 93]

The overnight models are still trying to resolve the potential of a weak wave around Christmas that could deliver a mix for many of us.

[Blizzard of 93]

Longer term, the GFS & Euro both are showing the potential of a more significant coastal type of storm towards New Year’s in response to      the -NAO blocking pattern that looks to become established the last week of tye month.

[mahantango#1]

[mahantango#1]

18 this morning.

[paweather]

55 minutes ago, Blizzard of 93 said:

Longer term, the GFS & Euro both are showing the potential of a more significant coastal type of storm towards New Year’s in response to      the -NAO blocking pattern that looks to become established the last week of tye month.

Looks good Blizz. Hope we can capitalize on one or both of these in the next few weeks

[Mount Joy Snowman]

Low of 26. Going to enjoy my last day of full snow coverage before the heavy rains hit tonight. Still a beautiful scene out there. Quite a memorable start to December. 

[pasnownut]

17 lowest i saw on car digi outside of brunnerville this AM.

as i stated the other day, pattern twds eoy looks to be flattening, w/ AO/NAO both headed into - territory.  PNA/EPO also - which says zonal baby.  As blizz suggested, which side of the boundary we are on is the challenge.  OP's seem to be catchin onto the regime shift and hopefully adjust to better looks.  How long does it last...million$$ question.

Lastly the wonky evolution early in the new year is rather fun to see, and a couple models showing wonkiness at varying levels, but we get snow, so I'm in for the ride no matter if we derail or not.  

[Itstrainingtime]

Low this morning of 22 which was far lower than I expected after the events of last evening. I had some sort of inversion that sent my temp from 30.2 at 8pm up to 36.8 at 9pm. Temp plateaued there and was still at 35.1 at midnight. Was able to shave off 13 degrees during the early morning hours. 

[pasnownut]

3 minutes ago, Mount Joy Snowman said:

Low of 26. Going to enjoy my last day of full snow coverage before the heavy rains hit tonight. Still a beautiful scene out there. Quite a memorable start to December. 

absolutely.  This has been a very nice December, no matter how it ends, and it doesnt look torchy terrible.  Yeah we'll have to suffer a bit, but thats normal and part of the gig.

Have a good day all.

[ChescoWx]

Today will be our mildest day since the day before Thanksgiving with highs in the mid to upper 40's. Rain heavy at times arrives after midnight and continues into tomorrow morning. Combined with the melting snow and ice we could see some local flooding. Temperatures will rise into the low 50's toward morning before a strong cold front passes through with maybe a thunderstorm and then temperatures crash tomorrow during the day reaching near freezing by 5pm. There is a wind advisory in effect tonight into tomorrow so watch for some power outtages in the usual spots across the county. We then look to see temperatures bouncing below normal on Saturday, Monday and near normal Sunday, Tuesday and Christmas Eve. Our next chance of some snow or rain looks possible by Tuesday.

[pasnownut]

2 minutes ago, Itstrainingtime said:

Low this morning of 22 which was far lower than I expected after the events of last evening. I had some sort of inversion that sent my temp from 30.2 at 8pm up to 36.8 at 9pm. Temp plateaued there and was still at 35.1 at midnight. Was able to shave off 13 degrees during the early morning hours. 

for the record keepers. 19-22 was the "runnin" average on way to Etown. which was at 25

[AccuChris]

HRRR showing a nasty “squall line” tomorrow morning


.

[Itstrainingtime]

14 minutes ago, AccuChris said:

HRRR showing a nasty “squall line” tomorrow morning


.

That'll be a fun rush hour event. 

[pasnownut]

47 minutes ago, Itstrainingtime said:

That'll be a fun rush hour event. 

tomorrow Santa is doing his "north loop" to Lock Haven, Susquehanna, and Bloom universities.  I picked a gem of a day to do it.  

[Mount Joy Snowman]

Thought this was a curious post by MU. Is he implying that one day in the low 50s qualifies as a “torch period”? I know he loves his warm weather but it seemed weirdly defensive to me and wasn’t sure who he was addressing. 

[TimB]

17 hours ago, ChescoWx said:

Poor Timmy where is that 50 plus degrees you were preaching about for Christmas Day earlier this week? LOL

Now do the 12z euro.

[mahantango#1]

DT: ✳️ ALERT POSSIBLE NEW ENGLAND. NYC / NORTH NJ / LONG ISLAND SNOWSTORM appox DEC 30 ✳️

 

1⃣ Be advised that this is a long way off folks! This possible scenario is based upon a extrapolation of a pattern shift which has NOT yet happened.

 

KEY POINT -- a forecast or scenario based upon an extrapolation always has the high risk of being wrong--- even if you really really love snow and winter and cold.  

 

  2⃣ The Christmas Day and 12/26 pattern looks there mild for most of the country east of the Rockies and SOUTH of Interstate 70. BUT the Trough in SE Canada and an East based -NAO in Iceland is able to do enough to flatten the Ridge in the Plains and Midwest so that the extreme warmth across the southern states does not push north of I-70 on either Christmas day or on 12/26.

 

 3⃣ There is good model agreement especially with the AI models and the European ensemble that the Iceland East based -NAO will continue to build or increase in size of power AND retrograde towards Greenland and Baffin Island by the end of DEC ,

 

 4⃣. This movement will cause a closed 500mb LOW to form in SE Canada which in turn lowers the heights over the Eastern US to allow another shortwave to drop towards the Middle Atlantic Coast

 

 5⃣ IF this shortwave energy is real …IF… it could cause a significant surface LOW to form off the Mid-Atlantic coast and bring accumulating snow possibly significant snow to New England/ NYC/ Northern NJ and Long Island around 12/30/25

 

6⃣ The THIRD image is valid JAN 2: the strong Ridge over the Plains / Midwest has now been suppressed significantly as the block Greenland continues to Retrograde towards Labrador and Quebec. The problem is the Deep Trough in western Canada that extends down the West coast. This Trough is partially associated with the PV in Northwest Canada.

 

7⃣ IF we can get that deep Trough in western Canada and the PAC NW to weaken or slide eastward ….IF… the entire pattern would see a significant flip and set up a potentially stormy cold first half of JAN   

 

  ▶️HOWEVER this is pure speculation as currently there is no sign of that actually happening. ◀️