Major Nor'easter snow storm (possible top 20) Noon Wednesday-Noon Thursday Dec 16-17, 2020

[Tatamy]

16 minutes ago, LibertyBell said:

Since you're in Bethlehem I'll ask you- did you get 30 inches in Jonas too?  I was on Long Island for it 4 miles from JFK where we did get it, but I know there was a sharp cut off to the north.  In PA my other home is one county north of Allentown, in Carbon county.  Did that area also see 30"?  I know south of I-80 was where the heaviest snows were and I'm south of I-80.  Do you know of any snowfall totals out of the Lehighton/Albrightsville/Lake Harmony/Bear Creek area (elevation around 2000 ft)?  Thanks!

 

I received 30” here.  The airport at Allentown measured 31.9”. Up in the Carbon Cty area that you are referring to totals were less with amounts ranging from 10 to 20” depending on your location.  That was near the northern edge of the storm’s effects.

[Nibor]

6z gfs fringes northern areas. Immediate NYC area still in the thick of the heaviest snowfall 10+

[wdrag]

Good Sunday morning everyone (Dec 13), still 3-4 days away from a big one-the largest since March 2018?. Follow NWS statements/watches and warnings for snow, wind damage and coastal flooding.

EC and GFS models differ on track and intensity of the 850 Low/500 MB short wave (slight neg tilt or not?) and so... while I adjusted the topic headline and first two lines of the topic... no overcommitment for me on how severe. 00z/13 GFS MOS is a bit weak on POPS - is that a sign of a southward trend?  

I like closed lows at 500MB e of Cape MAY NJ and then out to sea s of ACK to bury NYC in snow... others may see it different but since the EC track continues consistently closer to LI than the GFS through the 06z/13 cycle, I leave my downside options open. Have added graphics the ~0724z/13 WPC QPF which if occurs implies a major snow storm, with 1 foot amounts fairly widespread in our forum north of LI-I80. 

So, overall, I have no change to the topic considerations.  From my perspective, a widespread 6" or greater snowstorm is coming (including NYC and much of LI), even if sleet-rain mix in over NYC/LI up to I80 in NJ, which is a distinct possibility if little banded dry slots develop Wednesday night.  Max amount axis to me favors near I84 (snow ratios and 700MB frontogenesis) but that is said since I'm leaning with the consistently stronger, more northern EC/EPS solution.  I could be choosing the wrong solution.  One note on the EC... IF it's too strong at 700MB trying to close off a low over NNJ-LI, then the GFS will prevail.  I think the NAM will help us tomorrow morning and my guess is the NAM will favor a more robust northern solution, but no guarantee.

In the meantime: I think it's time to think about getting all Wednesday activities complete by around Noon, and plan to resumé after the Thursday cleanup (sometime Thursday afternoon or Friday). I expect considerable closures for Wednesday evening and Thursday morning activities in our forum (safety purposes).  Also,  while powder is expected n of I80 with temps only in the 20s, I can see power outages from 6" of wet snow somewhere LI, I95 corridor eastward in NJ, presuming the warmer EPS is correct.  Drifting snow can occur during the height of the storm and shortly after it's departure. Snow measuring may be difficult-snow boards cleaned every 6 hours and then add those 6 hourly totals.  

Graphics are: WPC qpf forecast issued 0724z/13, the 00z/13 EPS snowfall (10 to 1 ratio) - not the heavier Kuchera yet for the the powder area, the 00z/13 GEFS chance for 8+" of snow which is LI-I95 for the rooters of the GEFS and probs quite for high for this. 538A/13

 

[The 4 Seasons]

16 minutes ago, wdrag said:

Good Sunday morning everyone (Dec 13), still 3-4 days away from a big one-the largest since March 2018?. Follow NWS statements/watches and warnings for snow, wind damage and coastal flooding.

EC and GFS models differ on track and intensity of the 850 Low/500 MB short wave (slight neg tilt or not?) and so... while I adjusted the topic headline and first two lines of the topic... no overcommitment for me on how severe. 00z/13 GFS MOS is a bit weak on POPS - is that a sign of a southward trend?  

I like closed lows at 500MB e of Cape MAY NJ and then out to sea s of ACK to bury NYC in snow... others may see it different but since the EC track continues consistently closer to LI than the GFS through the 06z/13 cycle, I leave my downside options open. Have added graphics the ~0724z/13 WPC QPF which if occurs implies a major snow storm, with 1 foot amounts fairly widespread in our forum north of LI-I80. 

So, overall, I have no change to the topic considerations.  From my perspective, a widespread 6" or greater snowstorm is coming (including NYC and much of LI), even if sleet-rain mix in over NYC/LI up to I80 in NJ, which is a distinct possibility if little banded dry slots develop Wednesday night.  Max amount axis to me favors near I84 (snow ratios and 700MB frontogenesis) but that is said since I'm leaning with the consistently stronger, more northern EC/EPS solution.  I could be choosing the wrong solution.  One note on the EC... IF it's too strong at 700MB trying to close off a low over NNJ-LI, then the GFS will prevail.  I think the NAM will help us tomorrow morning and my guess is the NAM will favor a more robust northern solution, but no guarantee.

In the meantime: I think it's time to think about getting all Wednesday activities complete by around Noon, and plan to resumé after the Thursday cleanup (sometime Thursday afternoon or Friday). I expect considerable closures for Wednesday evening and Thursday morning activities in our forum (safety purposes).  Also,  while powder is expected n of I80 with temps only in the 20s, I can see power outages from 6" of wet snow somewhere LI, I95 corridor eastward in NJ, presuming the warmer EPS is correct.  Drifting snow can occur during the height of the storm and shortly after it's departure. Snow measuring may be difficult-snow boards cleaned every 6 hours and then add those 6 hourly totals.  

Graphics are: WPC qpf forecast issued 0724z/13, the 00z/13 EPS snowfall (10 to 1 ratio) - not the heavier Kuchera yet for the the powder area, the 00z/13 GEFS chance for 8+" of snow which is LI-I95 for the rooters of the GEFS and probs quite for high for this. 538A/13

 

What do you think of the massive differences between the GFS OP and GFSv16? The current beta GFS version is a much more northerly track and it also has support from the rest of the 00Z suite inlcuding ECMWF/UKMET/GEM. Infact the GFS is actually a bit north and tucked in versus EC/UK/GEM while the GFS OP is well south of that mean. 

Also what are your thoughts on watches. With such high confidence i could see them going up with the PM shift which is about the max threshold for a watch ~72hrs from start.

[wdrag]

2 minutes ago, The 4 Seasons said:

What do you think of the massive differences between the GFS OP and GFSv16? The current beta GFS version is a much more northerly track and it also has support from the rest of the 00Z suite inlcuding ECMWF/UKMET/GEM. Infact the GFS is actually a bit north and tucked in versus EC/UK/GEM while the GFS OP is well south of that mean. 

Also what are your thoughts on watches. With such high confidence i could see them going up with the PM shift which is about the max threshold for a watch ~72hrs from start.

For the benefit of my friends in the NWS, I tend not comment on WHEN watch-warning issuance, instead focusing on my impressions-considerations.

Help me out: GFSv16 - is that the parallel? I saw what you saw. I can tell already that WPC is leaning heavier and I think many of us on the forum are in favor. 

That said, NWS has Monday problem to deal with that may result in an advisory hazard for a portion of NJ (please see Monday topic).  If I was working, most folks know I tried to push (collaborate) the lead time successfully.  Watches are meant to verify 50% of the time (that's the purpose-a defined heads up with potential for failure, whereas the warning needs 80% success according to the NWS criteria, which sometimes limits warning issuance since impact is personal perception).

I think my prior colleagues tend to issue with more certitude- more conservative and not wanting to hype.  

IFFFF this scenario continues as as consistently outlined... That would be a 24 hour Watch from Noon Wed-Noon Thu... usually max watch lead time up to 60 hours (5 twelve hour forecast periods, today, tonight etc) is pushing it but for a 1 footer...and potential airport closures. My guess is a Monday morning issuance but with less staff, maybe it will be late today-depending on the 12z cycle and WPC-NWS collaboration.    I don't know what the social scientists say, but I'm all for lead time on high probability large events, similar to NHC.  I could see an issuance late today that this process will be collaborated between WPC Winter Wx Desk and multiple impacted offices from The Virginias-PA-NYS-New England.  These calls can take 30 minutes or more for every office to have a voice, around 130A and 130P. And this with not all the latest cycle guidance available. Thereafter,  it's a push to get a good clearly useable product out and with Covid staffing, not sure how they handle.   Think I'd like to leave this as is and let the NWS processes work as their guidance directs.

[Animal]

1 hour ago, Nibor said:

6z gfs fringes northern areas. Immediate NYC area still in the thick of the heaviest snowfall 10+

High Point park 4 inches...I 80 is near 14 inches..it happens..

[The 4 Seasons]

19 minutes ago, wdrag said:

For the benefit of my friends in the NWS, I tend not comment on WHEN watch-warning issuance, instead focusing on my impressions-considerations.

Help me out: GFSv16 - is that the parallel? I saw what you saw. I can tell already that WPC is leaning heavier and I think many of us on the forum are in favor. 

That said, NWS has Monday problem to deal with that may result in an advisory hazard for a portion of NJ (please see Monday topic).  If I was working, most folks know I tried to push (collaborate) the lead time successfully.  Watches are meant to verify 50% of the time (that's the purpose-a defined heads up with potential for failure, whereas the warning needs 80% success according to the NWS criteria, which sometimes limits warning issuance since impact is personal perception).

I think my prior colleagues tend to issue with more certitude- more conservative and not wanting to hype.  

IFFFF this scenario continues as as consistently outlined... That would be a 24 hour Watch from Noon Wed-Noon Thu... usually max watch lead time up to 60 hours (5 twelve hour forecast periods, today, tonight etc) is pushing it but for a 1 footer...and potential airport closures. My guess is a Monday morning issuance but with less staff, maybe it will be late today-depending on the 12z cycle and WPC-NWS collaboration.    I don't know what the social scientists say, but I'm all for lead time on high probability large events, similar to NHC.  I could see an issuance late today that this process will be collaborated between WPC Winter Wx Desk and multiple impacted offices from The Virginias-PA-NYS-New England.  These calls can take 30 minutes or more for every office to have a voice, around 130A and 130P. And this with not all the latest cycle guidance available. Thereafter,  it's a push to get a good clearly useable product out and with Covid staffing, not sure how they handle.   Think I'd like to leave this as is and let the NWS processes work as their guidance directs.

Yes. The GFSv16 is the parallel. Its a world apart from the OP and more in line with the UK/GEM/EC suite. 

Thanks for the reply and the insight, didn't mean to put any pressure on you or cause any potential issues. Thanks for hangin out with us and providing your wisdom!

[LibertyBell]

2 hours ago, Tatamy said:

I received 30” here.  The airport at Allentown measured 31.9”. Up in the Carbon Cty area that you are referring to totals were less with amounts ranging from 10 to 20” depending on your location.  That was near the northern edge of the storm’s effects.

I'm glad I was here on Long Island for that one!  

[uncle W]

when using the lame TWC winter storm names can you please add in the date of the storm because some of us don't know it or if you're like me and despise the names...

[LibertyBell]

6 minutes ago, uncle W said:

when using the lame TWC winter storm names can you please add in the date of the storm because some of us don't know it or if you're like me and despise the names...

I really think names are necessary because sometimes you have multiple big storms in a month (like Feb 2010) and it gets highly confusing, but I would opt for a more scientific naming scheme (for tropical cyclones too).  I can call it Jonas Jan 2016 or just Jonas 1/2016.  The decision to name itself is pretty scientific, as they go with areal coverage of winter storm warnings or population covered under winter storm warnings, whichever is reached first.  In Europe, all big storms are named (not sure of their criteria.)  I would also name big storms that dont meet snow criteria if they meet wind criteria (gale or storm warnings of a certain areal or population coverage).

 

[LibertyBell]

3 minutes ago, JoshSnow said:

I got 30 inches for that in the Bronx! It was the best storm but it didn’t last as much as I wanted it to. It was a 24hr storm probably even less.

lol I like Jonas 1/2016 better but I'd name it something else entirely, I dont like people names for any kind of weather event, not even for hurricanes.

I thought it was a 30 hr storm because we had one last long lasting band that went on until 7 am?

 

[LibertyBell]

Just now, JoshSnow said:

Maybe in Long Island my storm was done by late afternoon. That was a heck of a storm kept dumping all day!

Oh man yea it just kept dumping all day, 6 straight hours of blizzard criteria!  What was that other storm that was like a half version of that, I think that was in Jan too, but in 2017 or 2018?  Do you remember it- it had 3 straight hours of whiteout during the day and I think Boston beat their 2/1978 surge record.  We had two double digit snowstorms that winter.  

[bluewave]

27 minutes ago, The 4 Seasons said:

Yes. The GFSv16 is the parallel. Its a world apart from the OP and more in line with the UK/GEM/EC suite. 

 

They fixed the GFS cold bias with the v16. But now it has a warm bias compared to the other guidance. The 500 MB skill scores are a little lower than the current OP. That being said, I have no idea how it will do with this storm since it’s just 1 case. 

https://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

[LibertyBell]

Just now, bluewave said:

They fixed the GFS cold bias with the v16. But now it has a warm bias compared to the other guidance. The 500 MB skill scores are a little lower than the current OP. That being said, I have no idea how it will do with this storm since it’s just 1 case. 

https://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

lol it's always something... when will this become the default GFS and when are they retiring the current operational?

 

[bluewave]

Just now, LibertyBell said:

lol it's always something... when will this become the default GFS and when are they retiring the current operational?

 

I don’t know. But it seems like when you try to fix one model bias or error, it creates another one. The real model data that you want are local model model biases for the individual NWS offices. So you can say x model is having this bias for storms with y teleconnections in place around the NY Bight. But these general model statistics don’t go that local to include elements such as storm track.

[LibertyBell]

1 minute ago, bluewave said:

I don’t know. But it seems like when you try to fix one model bias or error, it creates another one. The real model data that you want are local model model biases for the individual NWS offices. So you can say x model is having this bias for storms with y teleconnections in place around the NY Bight. But these general model statistics don’t go that local to include elements such as storm track.

that kind of pinpoint specificity is exactly what I've wanted for awhile now, but it seems like the technology isn't there yet and at some point chaos/random effects may limit how accurate these models will ever become.

 

[LibertyBell]

6 minutes ago, JoshSnow said:

GEFS 6z are way east. That’s concerning honestly! I hope we don’t get fringed here!

I like it- it keeps the highly tucked in solutions like the Euro honest.  Hopefully we see a compromise of the two solutions in actuality.

 

[uncle W]

13 minutes ago, LibertyBell said:

I really think names are necessary because sometimes you have multiple big storms in a month (like Feb 2010) and it gets highly confusing, but I would opt for a more scientific naming scheme (for tropical cyclones too).  I can call it Jonas Jan 2016 or just Jonas 1/2016.  The decision to name itself is pretty scientific, as they go with areal coverage of winter storm warnings or population covered under winter storm warnings, whichever is reached first.  In Europe, all big storms are named (not sure of their criteria.)  I would also name big storms that dont meet snow criteria if they meet wind criteria (gale or storm warnings of a certain areal or population coverage).

 

its lame and confusing...years from now they will have to use the same names like they do with tropical storms...unless its historic they use the name again...

[wdrag]

3 hours ago, The 4 Seasons said:

Yes. The GFSv16 is the parallel. Its a world apart from the OP and more in line with the UK/GEM/EC suite. 

Thanks for the reply and the insight, didn't mean to put any pressure on you or cause any potential issues. Thanks for hangin out with us and providing your wisdom!

I like hanging out and tryin to provide some insight above and beyond straight model use... but it's still the models.  back in the 1970s we could outguess the models 'sometimes', because they only ran 2x/day, fewer models and so we knew the biases.  Not so today..,many models updated yearly.    For this storm, soon we have to frame actions..

 

No pressure: I remember my shifts in the office... daytime phones ring off the hook with how much this and that, - that's why it's important to have a venue such as this to sound off and discuss, but also I think there has to be a public product framing these event, to keep things in perspective.  I still worry, even on this one, hanging too far out.  So far (including 06z EC) we're on track excepting the GFS op and GEFS south. 

[crossbowftw3]

Just now, LibertyBell said:

I like it- it keeps the highly tucked in solutions like the Euro honest.  Hopefully we see a compromise of the two solutions in actuality.

 

I'd assume we'll eventually see the compromise play out but the million dollar question is where could there be a sharp gradient of snow (should there be one?) us northern folks are essentially hanging our hats on this one bullet point.

[the_other_guy]

18 minutes ago, LibertyBell said:

I really think names are necessary because sometimes you have multiple big storms in a month (like Feb 2010) and it gets highly confusing, but I would opt for a more scientific naming scheme (for tropical cyclones too).  I can call it Jonas Jan 2016 or just Jonas 1/2016.  The decision to name itself is pretty scientific, as they go with areal coverage of winter storm warnings or population covered under winter storm warnings, whichever is reached first.  In Europe, all big storms are named (not sure of their criteria.)  I would also name big storms that dont meet snow criteria if they meet wind criteria (gale or storm warnings of a certain areal or population coverage).

 

I don’t mind names if they were coming from a national weather service.

 

I don’t like names that were made for branding, sensationalism, and ratings.

 

I actually think it’s beneath us on this site to use weather channel names for winter storms

Just my opinion

 

[MJO812]

Gefs not budging

[MJO812]

3 minutes ago, JoshSnow said:

Tony you have the EURO 6z

Pretty similar to the  0z run

Eps coming out

[bluewave]

30 minutes ago, LibertyBell said:

that kind of pinpoint specificity is exactly what I've wanted for awhile now, but it seems like the technology isn't there yet and at some point chaos/random effects may limit how accurate these models will ever become.

 

The next big leap may be AI.

https://www.ecmwf.int/en/newsletter/163/news/ai-and-machine-learning-ecmwf

ECMWF is currently making a significant effort to support applications of artificial intelligence and machine learning and to identify how such applications may improve numerical weather prediction at the Centre. Many standard methods used by ECMWF scientists on a daily basis can be regarded as examples of machine learning. However, there has recently been a surge in new methods which have the potential to revolutionise the work of operational weather prediction centres. Such methods include the use of deep neural networks, which can learn the dynamics of very complex non-linear systems from data.

 

[MJO812]

Eps

[bluewave]

This storm will push up against one of the strongest 50/50 lows on record.

 

[crossbowftw3]

1 minute ago, bluewave said:

This storm will push up against one of the strongest 50/50 lows on record.

 

I'm interested to see what kind of impact that sub-940 low would have on Labrador.

[CIK62]

Talking about Covid staffing at NWS Offices----but how about the NYC Sanitation Dept. manpower situation?

Most important aspect of battling 1"/hour snow events is placement of manpower/equipment before start of the  snow.    Mayor Lindsay would tell you that if he were alive.

Models have been double digit and pretty steady since last Thursday, I would say.     KWO-35 just mentioning some snow w/o any amounts or Watches as of 8am. today(Sun. ).     Gotta be a Watch by this PM.  Otherwise they know something we don't.

[Allsnow]

Wow 

[MJO812]

Gefs