E PA/NJ/DE Winter 2025-26 Obs/Discussion

[rcostell]

Thanks for the clarification.  I was not aware of that. It seemed to me after a road is brined the road just stays wet and doesn't ice over until it get too diluted or washes off.

Brine lowers the freezing point of water… so roads “just stay wet” longer and lower temperatures… so your observation is correct, too.


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[Duca892]

That slop storm pops up again 

[JTA66]

Starting to get some fog out there, 27F/DP 26F

[Hurricane Agnes]

WWA issued for the I-95 corridor counties - 

Quote

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
242 PM EST Sat Jan 17 2026

DEZ001-NJZ016>019-PAZ070-071-101>106-180845-
/O.NEW.KPHI.WW.Y.0003.260118T1100Z-260119T0100Z/
New Castle-Salem-Gloucester-Camden-Northwestern Burlington-
Delaware-Philadelphia-Western Chester-Eastern Chester-Western
Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Norristown, Media, Kennett Square,
Perkasie, Honey Brook, Lansdale, Wilmington, Glassboro,
Morrisville, Pottstown, Camden, Cherry Hill, Philadelphia,
Collegeville, Oxford, Doylestown, West Chester, Pennsville,
Moorestown, Mount Holly, and Chalfont
242 PM EST Sat Jan 17 2026

...WINTER WEATHER ADVISORY IN EFFECT FROM 6 AM TO 8 PM EST SUNDAY...

* WHAT...Snow expected. Total snow accumulations between 1 and 3
  inches.

* WHERE...Portions of northern Delaware, southern New Jersey, and
  southeast Pennsylvania.

* WHEN...From 6 AM to 8 PM EST Sunday.

* IMPACTS...Plan on slippery road conditions.

* ADDITIONAL DETAILS...Snow may mix with rain for a time at the
  onset Sunday morning before becoming all snow by Sunday afternoon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. The latest road
conditions for the state you are calling from can be obtained by
calling 5 1 1.

&&

$$

Also a SPS for fog around the area that have some snowpack.

Currently below freezing here at 29 with dp 28,

[Kevin Reilly]

Clear wind calm 28f humidity 98% dew point 27f a bit of an inversion layer and lots of low level moisture left behind. 

[Ralph Wiggum]

1 hour ago, Duca892 said:

That slop storm pops up again 

I posted in the other sub last week but dont want to poke a hornets nest....this type of pattern progression (Jan 23-Jan 30 give or take a day) in a Nina has alot of potential. Also has a lot of potential heartbreak. I mentioned it before but this shouldnt be brushed over...as the PNA ridge begins to amplifying with energy riding the stj, the heights out ahead rise. Thus, the Jan 24 thing could very well slide N and W or at the very least the boundary may setup farther N than we would like. Subsequently, as the PNA fires and joins with the EPO ridge, the next big stj wave riding thru for the Jan 27-29 thing could end up suppressed or a slider. 

Again, Im not saying this will happen, but I do urge caution as the biggest fail potential with Jan 24-25 is cutter or boundary too far N, then the fail potential for Jan 27-29 shifts to suppression or slider. Yeah, there are some nice teases on the individual deterministic runs, but keep expectations in check.

At least we arent tracking a PAC puke pattern and have some chances. Thats all we know for sure right now.

[ChescoWx]

15 minutes ago, Ralph Wiggum said:

I posted in the other sub last week but dont want to poke a hornets nest....this type of pattern progression (Jan 23-Jan 30 give or take a day) in a Nina has alot of potential. Also has a lot of potential heartbreak. I mentioned it before but this shouldnt be brushed over...as the PNA ridge begins to amplifying with energy riding the stj, the heights out ahead rise. Thus, the Jan 24 thing could very well slide N and W or at the very least the boundary may setup farther N than we would like. Subsequently, as the PNA fires and joins with the EPO ridge, the next big stj wave riding thru for the Jan 27-29 thing could end up suppressed or a slider. 

Again, Im not saying this will happen, but I do urge caution as the biggest fail potential with Jan 24-25 is cutter or boundary too far N, then the fail potential for Jan 27-29 shifts to suppression or slider. Yeah, there are some nice teases on the individual deterministic runs, but keep expectations in check.

At least we arent tracking a PAC puke pattern and have some chances. Thats all we know for sure right now.

Steve great post!! The main point for folks if they like winter weather is that this has been a much different winter season then we have seen for many years. While no one knows if all this cold and pretty consistent below normal temps for the last many months ends in a lot of snow is unknown. So if you measure great winters by snow totals you could be disapointed as snow take a lot of timing in any spots outside of the lakes or mountains of New England here in the Northeast.

[Ralph Wiggum]

0z Hrrr is a 2 waver tomorrow...one 4am-10am then a more significant wave backing in 3pm-9pm.

When was the last tine we got Hrrr'd?

[anthonyweather]

0z Hrrr is a 2 waver tomorrow...one 4am-10am then a more significant wave backing in 3pm-9pm.
When was the last tine we got Hrrr'd?

It was spot on for today. Definitely interesting.


See if anything else catches on 00z tonight





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[JTA66]

3 minutes ago, Ralph Wiggum said:

0z Hrrr is a 2 waver tomorrow...one 4am-10am then a more significant wave backing in 3pm-9pm.

When was the last tine we got Hrrr'd?

Yesterday  

Yeah, I think it did that at 18z, too. Let’s see if anything else climbs onboard.

[JTA66]

Just now, anthonyweather said:

It was spot on for today. Definitely interesting.


See if anything else catches on 00z tonight





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Jinx

[Mikeymac5306]

Thread started for tomorrow. You scaredy cats! LOL! 

[Albedoman]

26 minutes ago, anthonyweather said:

It was spot on for today. Definitely interesting.


See if anything else catches on 00z tonight





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close to a norlun trough  yoou never know when tilts lol

[anthonyweather]

NAMS got a big shift towards the hrrr for late night redevelopment. Not enough for most us, but one more shift and we’re in.


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[anthonyweather]

Throws 1/2” into eastern pa late tomorrow night. , 1” into jersey


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[Duca892]

No matter what it ends up as GFS has showed next weekend run after run

[Heisy]

I feel like current radar doesn’t match models, I have more snow and there’s more precip over Nj than was expected by almost every model that I can tell. Unless I’m wrong?


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[Physicsteve]

Yeah, western snow shield seems more expansive than was modeled. Not mad about the location of low pressures for some coastal action. 

[Ralph Wiggum]

Another cool thing about this snow.It should linger around a little while with highs in the thirties and twenties this week.

[Duca892]

Suppression depression now on 12z GFS for next weekend 

[JTA66]

17 minutes ago, Duca892 said:

Suppression depression now on 12z GFS for next weekend 

In the olden days, that’s exactly where you’d want the GFS at this stage.

[Ralph Wiggum]

2 hours ago, JTA66 said:

In the olden days, that’s exactly where you’d want the GFS at this stage.

The ens means like a more Northerly track. Under the hood it seems there are a few members NW of us, a few big dogs in our region, and a cluster of weaker systems to the South...so the means could be skewed. Regardless, should make for a fun week of tracking. Glad I took vacation this week!

[Mikeymac5306]

5 minutes ago, Ralph Wiggum said:

The ens means like a more Northerly track. Under the hood it seems there are a few members NW of us, a few big dogs in our region, and a cluster of weaker systems to the South...so the means could be skewed. Regardless, should make for a fun week of tracking. Glad I took vacation this week!

You were about to use the B word weren't you? 

 

[Duca892]

3 hours ago, JTA66 said:

In the olden days, that’s exactly where you’d want the GFS at this stage.

“Big storms go north/west” remember it well. If that still rang true we would be in an absolutely amazing spot

[Newman]

Considering how well the AI models did with the weekend storm systems and in general (their verification scores are much better than their physics based versions), it makes sense to rely on them for the upcoming period. At the synoptic level, it's the best we have. All of that to say, the 18z AIGFS looks great for next weekend. The Euro AIFS was even better at 12z. Long ways to go

[Duca892]

Squash city again on GFS. Le sigh

[Ralph Wiggum]

42 minutes ago, Duca892 said:

Squash city again on GFS. Le sigh

Ensembles are North and the AI models are way North. AIFS is a massive hit here and the AIGFS is a crippling ice storm respectively:

 

[Duca892]

1 minute ago, Ralph Wiggum said:

Ensembles are North and the AI models are way North. AIFS is a massive hit here and the AIGFS is a crippling ice storm respectively:

 

In your experience and with the AI scores do you expect the GFS to follow them? I actually keep meaning to tag you because you did a great job mentioning possible suppression a few days ago 

[Ralph Wiggum]

6 minutes ago, Duca892 said:

In your experience and with the AI scores do you expect the GFS to follow them? I actually keep meaning to tag you because you did a great job mentioning possible suppression a few days ago 

AI guidance im told have good verification scores at this range. This is right now at day 6 considered their wheelhouse.

I am still concerned about suppression in this pattern but having some reliable guidance continue to move North makes me feel a little bit better.

I will say im my experience, 90% or more of the time, these high pressures or extreme cold tend to be overdone and things in general come North as we approach game time. This may be the 1 out of the 10 times though...so Im playing it cautious wrt my expectations.

[Newman]

6z AIFS would be a certified banger for Philly. Surface temps hover around 10-14° as you squeeze 1-1.5" of QPF into this cold dome.