Extreme Cold, Snow & Sleet: SECS 1/25 - 1/26

[cleetussnow]

Ruh roh.  

[nycsnow]

Just now, SACRUS said:

RRFS (Next-Generation Replacement)

Core dynamics

FV3 (Finite-Volume Cubed-Sphere)

Same dynamical core as modern GFS

Part of NOAA’s Unified Forecast System (UFS)

Grid / algorithm

Unstructured cubed-sphere grid

Variable resolution

No lateral boundary conditions

Seamless global → regional scaling

Yea it’s gonna replace it eventually, but it’s still unknown if it’s good or not it’s a prototype at this stage still I believe? 

[SACRUS]

1 minute ago, nycsnow said:

Yea it’s gonna replace it eventually, but it’s still unknown if it’s good or not it’s a prototype at this stage still I believe? 

Yes but the core is based more on the GFS systems

[SACRUS]

 

12z RRFS 

Total QPF

 

 

Total Snow

 

 

[mulen]

Been along time since I viewed this board go all the way back to the TWC days good look dudes no snow googles been in Florida 10 yrs so I watch from afar .

[hudsonvalley21]

26 minutes ago, donsutherland1 said:

On a more serious note regarding the NAM, the RGEM's high-resolution model and most of the global models use 4dVAR (four-dimensional variation) initialization. The NAM uses the older 3dVAR (three-dimensional variation) initialization. The general idea of warmer air moving in to change the snow to sleet in coastal areas and the New York City area and its nearby suburbs is the baseline idea due to lots of support. It's uncertain whether the NAM is overdoing things on account of its older initialization scheme or if it sees something the other guidance doesn't. If it begins to adjust late today (18z or later), that could be an indication that the older initialization process was playing a role. If, on the other hand, the other guidance starts shifting, that will indicate that the NAM, despite its limitations, had correctly resolved some of the details ahead of the other guidance.

Another thought Don is the start time to what the models are showing. The cold dry air in place might hold off for the snow to reach the surface for some time more till the columns saturate especially points north of NYC. Currently 7/-8 

[jm1220]

9 minutes ago, SACRUS said:

 

12z RRFS (new / replace NAM)

 

Snow by 3/4AM

 

 

Snow through 2PM before mixing with sleet

 

 

 

 

Yeah, if there's sleet pushing to I-80 in PA then all the way to Hartford NYC is screwed for any kind of big event. Again it's one possible outcome but the other cold models need to hold on today.

[SACRUS]

 

1/24 12z ICON 

 

[hooralph]

The NAM is the Aaron Rodgers of models

• Clearly ready for the exit
• Was always flawed but racked up some big wins in its career
• Problematic in ways that distract from its strengths (but fans like it for being "contrarian")
• People vigorously rooting for it to lose
• Still capable of some key plays that make it impossible to write off

 

[SACRUS]

12z ICON

 

 

[SACRUS]

[RU848789]

Just caught up and surprisingly, didn't see the NWS snow/ice maps, so here they are.  I had also summarized all of the NWS-Philly/NYC warnings elsewhere, so sharing them here.  Nice to see the NWS finally bringing snowfall forecasts in line with the models and most other forecasters - I think a general 8-12" of snow and sleet for most S of 78 and more N of there and NE through NYC and the LHV/CT is pretty good.  The NWS has me at 11.9" of snow/sleet, which I think is still a little high, so I'll go with 10.4" for Metuchen.  

NWS-Philly Counties

• For Sussex-Warren-Carbon-Monroe-Lehigh-Northampton, the warning is for 11-15" of snow/sleet, but no freezing rain (ZR)
• For counties in PA/NJ south of 78 (except coastal counties south of Ocean), i.e.,Hunterdon-Somerset-Middlesex-Monmouth-Mercer-Salem-Gloucester-Camden-Burlington-Ocean-Cumberland-Berks-Delaware-Philadelphia-Chester-Montgomery (and Newcastle/Kent in DE), the warnings are for 7-13" of snow and sleet with up to 0.3" of freezing rain accretion, especially SW of Trenton as per the ice map below.
• For Atlantic/Cape May counties and southern DE, the warning is for 4-8" of snow/sleet plus about 0.1" ZR

NWS-NYC Counties

• For W. Passaic, the entire Hudson Valley and the coastal CT counties, the warning is for 12-16" of snow
• For NENJ (Union/Essex/Hudson/Bergen/E Passaic), NYC and LI, the warning is for 10-14" snow/sleet plus a light glaze of ZR

 

[SACRUS]

[allgame830]

1 minute ago, SACRUS said:

Definitely way colder than the NAM

[donsutherland1]

3 minutes ago, hudsonvalley21 said:

Another thought Don is the start time to what the models are showing. The cold dry air in place might hold off for the snow to reach the surface for some time more till the columns saturate especially points north of NYC. Currently 7/-8 

Yes. I agree. The steady snow might not arrive in the Hudson Valley until 13z or 14z (northern Hudson Valley). 

[WestBabylonWeather]

If this continues the 11” forecast at islip from NWS is going to lower. 

[SACRUS]

 

1/24 12z ICON

 

Total QPF

 

Total Snow / Sleet (10:1)

[RU848789]

1 minute ago, donsutherland1 said:

Yes. I agree. The steady snow might not arrive in the Hudson Valley until 13z or 14z (northern Hudson Valley). 

Damn, now we have to worry about the sun angle...at 15F, lol.  

[SACRUS]

 

1/24 14z RAP has snow starting around 4/5 AM

 

[nycsnow]

Icon is colder than nam and in nyc area it’s only .5- inch different from 06z so I’d say it held steady??

[Monty]

8 minutes ago, mulen said:

Been along time since I viewed this board go all the way back to the TWC days good look dudes no snow googles been in Florida 10 yrs so I watch from afar .

We were talking about you and others in the obs thread a few days ago Glad to see you seeya

[SACRUS]

[NJwx85]

Honestly, while the threat for sleet at the end is increasing somewhat, many here are way overreacting. Take a compromise and you get one heck of a snowstorm for just about everyone.

[WIN]

Regardless of which models are right, it appears we're in for a general 6 to 12 inch snowfall before any mix/change. 

I cannot believe that so many are miserable about that. 

[ILoveWinter]

Just now, SACRUS said:

Queue the "it's still snowing in Nashville and it was supposed to changeover to sleet already so that's a good sign for us" posts lol

[gravitylover]

12 minutes ago, mulen said:

Been along time since I viewed this board go all the way back to the TWC days good look dudes no snow googles been in Florida 10 yrs so I watch from afar .

It's good to see ya dude! Hope all is well.

[Astoriaweather]

6 minutes ago, WIN said:

Regardless of which models are right, it appears we're in for a general 6 to 12 inch snowfall before any mix/change. 

I cannot believe that so many are miserable about that. 

I am thinking 5 to 8 in NYC, but at this point I will be satisfied with that, especially if the sleet helps it form into a glacier afterwards. . I guess my one worry is that things just keep trending bad until game time and even 5 is not within reach in the urban, coastal core. Hope I am wrong.  

[eduggs]

58 minutes ago, MJO812 said:

We shall see. Nam can be amped but cant discount it since this is a new run.

We go through this so often. And people cover their eyes and ears beforehand and pretend it didn't happen afterwards. When the NAM shows sleet it sleets. And the extent is usually north of where the 3rd party vendor graphics show it.

[eduggs]

This reminds me a lot of December 16/17 2020.  I don't think the public freakout was as over-the-top for that one... but then again, people didn't have the apple weather app yet I don't think.

[Astoriaweather]

Besides the thermals, I guess I also worry that the storm ends up moving past us even faster than models suggest it will.  It seems that often ends up happening, unless its a prolonged overrunning or crawling coastal.   There have been plenty of times where we expect storms to last 12 hours but in reality they pass by in about 8 to 10.