Extreme Cold, Snow & Sleet: SECS 1/24 - 1/26

[MJO812]

5 minutes ago, jm1220 said:

We all know the tendency for these to trend north over time. 

Not in every case especially with very cold air in place before the storm.

[SACRUS]

NAM at 84 FWIW:

 

[Rjay]

6 hours ago, psv88 said:

That’s not what you meant haha. Warm and wet implies rain. Stop it

No he didn't. He also knows what he's looking at.  I have no idea why you guys are getting annoyed with him. 

[NEG NAO]

Notice  that Mt. Holly's Winter Storm Watches only include mixing in their southern zones

WSW from KPHI

[Jt17]

good morning i see stuff trended north this morning. still plenty of time for this to come a little south and hit us like the GFS! 
 
Id like to say this, i'd rather have GfS than Euro at this range!

Things got better overnight besides Euro and Icon (which took a step back)


.

[RU848789]

30 minutes ago, sussexcountyobs said:

Mt. Holly:

KEY MESSAGE 2...A significant winter storm appears increasingly
likely Saturday night through Monday morning. Substantial snow
accumulations will be possible across much of the area. Some
mixed precipitation is expected as well.

A closed mid-level low off the southwestern coast of CA will
gradually open and pivot northeastward, eventually phasing with
the northern jet as it approaches our region. This will place
our entire region in the left exit region of a potent trough.

Synoptic scale ascent is expected to begin overspreading the
region by Saturday evening. As surface low pressure begins to
approach from the southwest, precipitation is expected to begin
overspreading the region from southwest to northeast Saturday
night. Given the very cold airmass in place initially,
precipitation is expected to start as all snow. As the vertical
column moistens, snow rates may quickly become heavy, with rapid
accumulations possible.

During the day on Sunday, additional surface cyclogenesis is
expected off the Mid-Atlantic coast, with the surface low
tracking northeastward. The primary remaining uncertainty with
this forecast is the exact low track. In general, guidance
continues to suggest a low track fairly to the coast, with the
GFS as a relative outlier a little bit farther out to sea. Given
this low track, it is becoming increasingly likely that sleet,
freezing rain, and even plain rain will enter the picture for
parts of the area during the day on Sunday. Right now, this
appears most likely from about the Philadelphia metro and south,
and perhaps farther north for the Coastal Plain. While this
could decrease snow totals some, exactly where mixing occurs
remains uncertain, and confidence remains high in significant
snow accumulations. In addition, mixed precipitation would still
cause significant issues. For this region, DESI probabilities
of exceedance for warning criteria snow (5 inches) are over 90%.
Depending on how soon, and to what extent, mixing occurs,
amounts could exceed 10 inches for this area. Outside of the
aforementioned areas, all snow is expected, with significant
accumulations likely. DESI probabilities of exceedance for
warning level snow (6 inches) across the remainder of our
eastern PA and northern NJ counties are over 90%. In fact,
probabilities of exceeding 10 inches are 70-90%.

Going to be an interesting modeling battle from now until the event on when and if and where any mixing/changeovers occur and how much snow falls before any mix/changeover. I hope Mt. Holly is right about all snow N of 276/195, essentially.  

One comment for those who don't love snow (and who might root for less snow here): I think you'd rather have 15" of snow (which is easy to move) than 10" of snow, 1" of sleet and 0.2-0.3" of freezing rain on top, as the latter will lead to compaction and a fairly quick freeze into a potentially solid mass within a few hours, as temps in areas where we see freezing rain/rain will dop well below 32F within a few hours of the precip ending - temps everywhere will be in the mid-20s everywhere by Monday at 7 am and will stay there during the day with Monday night lows around -5 to +5F - and it might not reach 20F again until next Sunday. It's going to get really cold.  

[TJW014]

GFS would be perfect here for all of us. Otherwise just let it rain. Don't care if I get 6" from a front thump. If it ends as 3" of slush, what's the fun in that?

[Jersey_Snowhole]

3 minutes ago, NEG NAO said:

Notice  that Mt. Holly's Winter Storm Watches only include mixing in their southern zones

WSW from KPHI

And coastal sections 

[RU848789]

3 minutes ago, NEG NAO said:

Notice  that Mt. Holly's Winter Storm Watches only include mixing in their southern zones

WSW from KPHI

Yep, essentially all snow N of 276/195 in PA/NJ (except they included Ocean in that, which is surprising, as I'd think they'd changeover like the rest of SNJ).  

[binbisso]

43 minutes ago, Tatamy said:

Look at the temps at 700mb and 850mb.  It gives a different picture of the event precip wise.  Be sure to look at 96 and 102 hours.

700, 950 and 925 are all <0c from the city south at those times 

[EastonSN+]

45 minutes ago, EasternLI said:

Maybe. Wish more levels were available. Even if that happens the precip is about to shut off anyway I think with a dry slot. We'd have a good dump anyway before that. Still a ways to go with this thing. Should be fun to see what happens. 

The Middle Atlantic forum had a good analysis of the 6z suite. 

They mentioned that the AI actually was a touch south and increased snow a bit on the southern edge. They have the comparisons posted which is great. 

They also mentioned the EURO held. 

Great run IMO:

AI south a bit

EURO held

At the very least this rapid northern trend has halted for now. 

[binbisso]

35 minutes ago, bluewave said:

Yeah, they don’t have p-types for that model. So we just have to estimate the p-types from the thickness values and compare to the Euro which has p-types. My guess is that we are going to get a very heavy front end thump on Sunday with at least 6-8” potential before any mixing. This has been the case with past SWFEs. We just have to watch the Southeast ridge next few days in the forecasts to refine the amounts. 

Pivital has them

[NEG NAO]

Just now, RU848789 said:

Going to be an interesting modeling battle from now until the event on when and if and where any mixing/changeovers occur and how much snow falls before any mix/changeover. I hope Mt. Holly is right about all snow N of 276/195, essentially.  

One comment for those who don't love snow (and who might root for less snow here): I think you'd rather have 15" of snow (which is easy to move) than 10" of snow, 1" of sleet and 0.2-0.3" of freezing rain on top, as the latter will lead to compaction and a fairly quick freeze into a potentially solid mass within a few hours, as temps in areas where we see freezing rain/rain will dop well below 32F within a few hours of the precip ending - temps everywhere will be in the mid-20s everywhere by Monday at 7 am and will stay there during the day with Monday night lows around -5 to +5F - and it might not reach 20F again until next Sunday. It's going to get really cold.  

the more actual ice - sleet etc and rain make the snow much heavier to shovel - high ratio snow can actually be removed with a powerful leaf blower if you keep up with it from when it starts accumulating

[donsutherland1]

8 hours ago, Nibor said:

@donsutherland1 Do you know which models got the recon data?

It's my understanding that all the global models and NAM got it. The recon data is pulled into the 4dVAR (GGEM, ECMWF, UKMET, ICON) and FV3 (American models) initialization packages.

[kat5hurricane]

It's looking more like a SWFE with a heavy thump to ice mess as opposed to the cold long duration storm it looked like a few days ago but 6-8"+ is nothing to sneeze at especially after recent winters. My concern is that these things tend to trend north and we can't afford many more trends north close to the city at least, I think everybody NW of the city are sitting pretty now.

[psv88]

4 minutes ago, Jt17 said:

Things got better overnight besides Euro and Icon (which took a step back)


.

Even the Icon never got above 30 degrees out here in inland western Suffolk. North of the southern state parkway stays below freezing on even the warmest models.
 

Extreme south shore of the island spikes to 34 for a few hours early Monday morning before temps crash again. This is on the warmest model. 

[WestBabylonWeather]

We were begging for north trends on Monday. This movie has played out so many times. 

[NEG NAO]

2 minutes ago, donsutherland1 said:

It's my understanding that all the global models and NAM got it. The recon data is pulled into the 4dVAR (GGEM, ECMWF, UKMET, ICON) and FV3 (American models) initialization packages.

and what changed in the model output with this additional input ?

[NEG NAO]

1 minute ago, kat5hurricane said:

It's looking more like a SWFE with a heavy thump to ice mess as opposed to the cold long duration storm it looked like a few days ago but 6-8"+ is nothing to sneeze at especially after recent winters. My concern is that these things tend to trend north and we can't afford many more trends north close to the city at least, I think everybody NW of the city are sitting pretty now.

not according to Mt. Holly

WSW from KPHI

[Jt17]

It's looking more like a SWFE with a heavy thump to ice mess as opposed to the cold long duration storm it looked like a few days ago but 6-8"+ is nothing to sneeze at especially after recent winters. My concern is that these things tend to trend north and can't afford many more trends north close to the city at least, I think everybody NW of the city are sitting pretty now.

This just isn't what the guidance has shown at 0z or 6z - you're hugging the Euro alone if you think it's looking more like a short thump of 6-8 before turning over.


.

[Snowman92]

What was the saying ?

"Big storms go north" or something like that

[NEG NAO]

2 minutes ago, Snowman92 said:

What was the saying ?

"Big storms go north" or something like that

only when the high to the north is NOT as strong and anchored like this weekends will be - this is a Miller B setup redevelopment off the coast sooner then later

[EastonSN+]

Also yesterday Forky said he's not worried. Until/if Forky amends his statement.

[kat5hurricane]

4 minutes ago, Jt17 said:

This just isn't what the guidance has shown at 0z or 6z - you're hugging the Euro alone if you think it's looking more like a short thump of 6-8 before turning over.


.

I'm looking at trends. Outside of the flatter GFS which is a garbage model lets be honest and a follower more than a leader, most other models are starting to introduce a warm layer that cuts down on totals somewhat and this might not be done trending, that SE Ridge often times plays a factor. Regardless, the floor looks to be a significant snow before any changeover so it's not a bad place to be.

[EastonSN+]

So far 6z

EURO held

EURO AI nudged south and colder.

GFS looked amazing but not waisting much time on it.

[Rmine1]

Personally, I’m just glad that we only have THREE more days to watch the back and forth, and the corresponding play by play. 
 

 

[MarcmmKU]

Any chance we can get 10" before the sleet starts in nyc?

[donsutherland1]

6 minutes ago, NEG NAO said:

and what changed in the model output with this additional input ?

I don't think anyone outside of NCEP can answer that, as one has no comparison to a control case (the model solutions without the additional data). 

Another flight is scheduled for 1/23 0z.

000
NOUS42 KNHC 211739
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1240 PM EST WED 21 JANUARY 2026
SUBJECT: WINTER SEASON PLAN OF THE DAY (WSPOD)
         VALID 22/1100Z TO 23/1100Z JANUARY 2026
         WSPOD NUMBER.....25-052 CORRECTION

I.  ATLANTIC REQUIREMENTS
    1. FLIGHT ONE - NOAA 49
       A. 23/0000Z
       B. NOAA9 03WSA TRACK66
       C. 22/2015Z
       D. 10 DROPS AS PUBLISHED ON TRACK BEGINNING WITH DROP POINT 3    
          AND ENDING WITH DROP POINT 2.
       E. AS HIGH AS POSSIBLE/ 22/2030Z TO 23/0230Z.

    2. OUTLOOK FOR SUCCEEDING DAY: POSSIBLE MISSION ALONG TRACK 66 
       FOR 24/0000Z.

II. PACIFIC REQUIREMENTS
    1. FLIGHT ONE - TEAL 75
       A. 23/0000Z
       B. AFXXX 12WSE IOP11
       C. 22/1830Z
       D. 25 DROPS APPROXIMATELY 60 NM APART WITHIN AN AREA BOUNDED 
          BY: 35.0N 130.0W, 35.0N 110.0W, 15.0N 110.0W, 
          AND 15.0N 130.0W
       E. AS HIGH AS POSSIBLE/ 22/2030Z TO 23/0230Z

    2. SUCCEEDING DAY OUTLOOK: A USAF WC-130J AIRCRAFT MAY FLY AN 
       ATMOSPHERIC RIVERS MISSIONS OVER THE EASTERN PACIFIC FOR THE 
       24/0000Z SYNOPTIC TIME.
    3. ADDITIONAL DAY OUTLOOK: TWO USAF WC-130J AIRCRAFT MAY FLY 
       ATMOSPHERIC RIVERS MISSIONS OVER THE CENTRAL AND EASTERN 
       PACIFIC FOR THE 25/0000Z SYNOPTIC TIME.

[Jt17]

How does 6z EPS look compared to 0z?


.

[WeatherGeek2025]

right now as it stands every model shows 6-12 inches of snow followed probably by a bunch of sleet. The GFS is the only model that shows pure snow for the city and west if you use kuchera probably getting around 12-18 inches according to GFS. Hopefully the GFS is right. Even if the other models that are showing that warm nose aloft it's fine we're still getting a good amount of snow followed by heavy sleet which will have staying power for our snow cover for weeks!