January 25-26 Winter Storm Potential

[Ralph Wiggum]

6z GFS upped the ante:

 

[MickeyTim6533]

6Z is a crush job

[Ralph Wiggum]

6z rgem  had 4-6" snow before plowing the mix line due N and turning to sleet

[Ralph Wiggum]

6z gefs is a thing of beauty. Minimal mixing. Seems things have settled down since the pac data was ingested last night.

[Newman]

GEFS and GFS are near mint perfect, which has me nervous because they're always cooler and more progressive. We're going to see some crazy QPF bombs with our CAMs in the next few days.

[Ralph Wiggum]

AI euro drops about 11" before ending as a mix.

[Duca892]

23 minutes ago, Ralph Wiggum said:

6z rgem  had 4-6" snow before plowing the mix line due N and turning to sleet

That trend simply terrifies me and why I feel pretty ok saying 6-8in for many before the slop 

[wkd]

On the 06Z gfs the temps at 850 and 700mb never get above 32F.  No sleet.

[Newman]

30 minutes ago, Ralph Wiggum said:

AI euro drops about 11" before ending as a mix.

Ticked colder, so did the 06z Ukie with heights lower/confluence stronger over southern Canada.

[Newman]

At the surface, high pressure has actually ticked stronger and further south at storm onset with deeper CAD down the spine Of the Appalachians. This can certainly help with keeping the sleet at bay, but again the warm nose is up at at 700mb level so it can only do so much if we still drive the primary up into WV or SW PA.

[Kevin Reilly]

1 hour ago, Ralph Wiggum said:

6z GFS upped the ante:

 

Guessing that’s the new injested data now from Hurricane Hunters?

[Kevin Reilly]

12 minutes ago, Newman said:

At the surface, high pressure has actually ticked stronger and further south at storm onset with deeper CAD down the spine Of the Appalachians. This can certainly help with keeping the sleet at bay, but again the warm nose is up at at 700mb level so it can only do so much if we still drive the primary up into WV or SW PA.

It definitely looked like the high up north beats it down a bit.  I wonder if it continues to beat it down a bit more as we get closer to game. 

[Mikeymac5306]

What we don't need is .25 of ice on top of 12+" of snow. 

[Albedoman]

23 minutes ago, Newman said:

At the surface, high pressure has actually ticked stronger and further south at storm onset with deeper CAD down the spine Of the Appalachians. This can certainly help with keeping the sleet at bay, but again the warm nose is up at at 700mb level so it can only do so much if we still drive the primary up into WV or SW PA.

The 1035 HP  is still in play saying it for days

[Albedoman]

7 minutes ago, Mikeymac5306 said:

What we don't need is .25 of ice on top of 12+" of snow. 

1994 all over again folks if that happens

 

[Violentweatherfan]

9 minutes ago, Albedoman said:

1994 all over again folks if that happens

 

I think it’ll be sleet, what also concerns me is the redevelopment off the coast might bust. 
 

Also am I seeing the 6Z GFS has no sleet/ZR in our area?

Edit: let’s not forget the dry slot potential 

[Eskimo Joe]

47 minutes ago, Newman said:

At the surface, high pressure has actually ticked stronger and further south at storm onset with deeper CAD down the spine Of the Appalachians. This can certainly help with keeping the sleet at bay, but again the warm nose is up at at 700mb level so it can only do so much if we still drive the primary up into WV or SW PA.

It also drove the primary further south into Alabama. Good things for snow lovers.

[The Iceman]

Extremely bullish briefing by mt holly. Wow.

 

https://www.weather.gov/media/phi/current_briefing.pdf

[Hurricane Agnes]

8 hours ago, beer said:

couldn't you just put some epoxy ?

It looks like the bottom part has separated.  I don't normally keep the inner tube in there for winter but keep the outer one for when I might want to calculate snow ratios.  I forgot it was still in there.   I may end up going on and getting a new one as this one has gotten battered over the years.  I mainly used it to verify my weather station.

I didn't see if anyone posted the 6z ICON but if not, here it is (looks like the amounts are cut down as other models have shown) - 

[Hurricane Agnes]

Here's the Winter Storm Watch up for Philly metro - 

Quote

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
212 AM EST Thu Jan 22 2026

DEZ001>004-MDZ012-015-019-020-NJZ016>019-021>025-027-PAZ070-071-101-
102-104-222015-
/O.NEW.KPHI.WS.A.0001.260125T0000Z-260126T1800Z/
New Castle-Kent-Inland Sussex-Delaware Beaches-Kent MD-Queen
Annes-Talbot-Caroline-Salem-Gloucester-Camden-Northwestern
Burlington-Cumberland-Atlantic-Cape May-Atlantic Coastal Cape May-
Coastal Atlantic-Southeastern Burlington-Delaware-Philadelphia-
Western Chester-Eastern Chester-Eastern Montgomery-
Including the cities of Norristown, Atlantic City, Easton, Honey
Brook, Rehoboth Beach, Centreville, Cape May Court House, West
Chester, Denton, Pennsville, Moorestown, Cherry Hill, Media,
Kennett Square, Mount Holly, Chestertown, Wharton State Forest,
Wilmington, Oxford, Hammonton, Lansdale, Georgetown,
Philadelphia, Millville, Ocean City, Glassboro, Camden, and Dover
212 AM EST Thu Jan 22 2026

...WINTER STORM WATCH IN EFFECT FROM SATURDAY EVENING THROUGH MONDAY
AFTERNOON...

* WHAT...Heavy snow and significant snow accumulations likely.
  Precipitation may mix with sleet and freezing rain on Sunday.

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

* WHEN...From Saturday evening through Monday afternoon.

* IMPACTS...Travel could be very difficult. The hazardous conditions
  could impact the Monday morning commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts for updates on this situation.

&&

$$

 

[ChescoWx]

[Violentweatherfan]

The redevelopment of the low, if any will be key

GFS has it tracking away from the coast and the Euro hugs the coast 

[Ralph Wiggum]

37 minutes ago, Violentweatherfan said:

The redevelopment of the low, if any will be key

GFS has it tracking away from the coast and the Euro hugs the coast 

Not just this but ive been watching it develop off of SC, then off of NC (this was when we were looking golden), and now develops at the mouth of the Chesapeake Bay down near VA Beach. If this is the case, ie develop it farther N and W, then we need the low to go East from there. Keep an where 12z develops the 2ndary...more east is better here.

 

[ChescoWx]

CAMS will be a great tool to see the mids warm. Below is the 6z NAM through 1pm

[Violentweatherfan]

Hey @Newman what are CAMS

[Ralph Wiggum]

12z NAM, which shouldn't be taken verbatim at this range, develops the coastal low way west of its 6z run and tucks it and crawls it N-NNE. 

That scenario does us no good as mid levels torch and coastal is hugging the coast. Unless it bombs out and stalls, would just end as sleet and ice whereas some guidance had levels crashing and a ccb wraparound developing giving us a 'part 2' of accum snow. Will just have to watch where other guidance develops the coastal and the strength.

[MGorse]

1 hour ago, The Iceman said:

Extremely bullish briefing by mt holly. Wow.

 

https://www.weather.gov/media/phi/current_briefing.pdf

We finally switched to the new format/slides as well. 

[Newman]

13 minutes ago, Violentweatherfan said:

Hey @Newman what are CAMS

Convection Allowing Models

[ChescoWx]

The latest NAM through 4pm with looking at how close the upper level temps are to freezing looks like sleet already at most spots across at least Chesco and up to close to Reading....but the damage has been done. 

[Duca892]

1 minute ago, ChescoWx said:

The latest NAM through 4pm with looking at how close the upper level temps are to freezing looks like sleet already at most spots across the area....but the damage has been done. 

This is a really stupid question, so when i am looking at the 1st pic where for Allentown it says "-4" does that indicate that the upper levels are at 28 degrees (4 degrees less than freezing) and that Allentown is still snow?