NYC/PHL 12/21-12/22 Threat

[Thunder Road]

Isn't this another case where the shortwave needs to phase with the northern stream or else we just see a weak disturbance heading east and OTS? Seems like another thread the needle event where we need the confluence to be weaker and more amplification and phasing although this is more Nina-esque than the last threat. Appears to be strong miller B like system on the gfs.

it's a west-to-east mover, and if you read the thread at all you would see what makes this such a legit threat is that it's NOT a thread-the-needle. Not that the 12z GFS is right for DC, but even w/o a phase or coastal pop we end up with several inches.

[RowanBrandon]

Did the GFS ever have the previous storm for 5 straight runs this far out?

[Sampson]

Total 60 hrs precip through 192 hrs.

Hopefully this doesn't end up as one of those Norfolk to Boston storms that DT has been advertising. Looks great as of now, and has certainly added a lively verse to the current winter blues we're all experiencing. A few flakes on Christmas day would suffice but this could truly end up being a christmas miracle....

on my way to church

[MJO812]

Did the GFS ever have the previous storm for 5 straight runs this far out?

Nope. It showed a big snowstorm for 2 runs straight.

[SACRUS]

ggem at 144 \\\

[Alpha5]

it's a west-to-east mover, and if you read the thread at all you would see what makes this such a legit threat is that it's NOT a thread-the-needle. Not that the 12z GFS is right for DC, but even w/o a phase or coastal pop we end up with several inches.

Exactly we have a large piece of energy that breaks off from the PAC NW ULL and digs really far south....a phase is great, but its not like the last storm where were dealing with tiny sw's that needed a thread the needle situation

[Jaguars]

it's a west-to-east mover, and if you read the thread at all you would see what makes this such a legit threat is that it's NOT a thread-the-needle. Not that the 12z GFS is right for DC, but even w/o a phase or coastal pop we end up with several inches.

Exactly, I always liked these 'bowling balls'. Not a true miller a or b but almost sort of a hybrid and more margin for error. There is nice over-running and then the low slowly climbs NE towards the benchmark. Very nice looking storm approaching the medium range. This most likely doesn't have any makings of a KU but a nice 3-6 swath and some 6-12 jackpots.

[Feb]

I don't know why the gfs blows this storm so much off along and off the coast for Christmas, it seems highly unlikely in the pattern we're in. The system kind of looks like your typical clipper but with a little kick, it'll probably get stronger as it treks east but nowhere near as strong as the gfs indicates. Also, there's a possibility that the confluence shreds it apart before it can do anything which is why I'm not concerned at this moment. I do hope to have some snow on Christmas, but maybe that's asking for too much.

You must be a joy at parties. People probably lining up just to hang themselves.

And in the general forum, Wes is starting to get on board for this one. That speaks for itself.

[SnowGoose69]

Norlun signature continues to get stronger on the 12Z runs for west-central LI and perhaps event CT tomorrow night....will have to see what further model runs bring but definitely nowcasting potential tomorrow evening.

[Sampson]

You must be a joy at parties. People probably lining up just to hang themselves.

And in the general forum, Wes is starting to get on board for this one. That speaks for itself.

He prefers the "glass half broken" approach.

[MJO812]

12z GFS ensemble mean . Good agreement this far out.

[hazwoper]

Jetski - this system for Xmas is NOT a clipper.

[Feb]

He prefers the "glass half broken" approach.

He almost makes Colin out to be a motivational speaker.

[blizzardof09]

Norlun signature continues to get stronger on the 12Z runs for west-central LI and perhaps event CT tomorrow night....will have to see what further model runs bring but definitely nowcasting potential tomorrow evening.

What would the norlun signature bring to long island if it were to come to fruition?

[Sampson]

The wrong week.....

[SnowGoose69]

What would the norlun signature bring to long island if it were to come to fruition?

A coastal front would setup somewhere, if you believe the 12Z Models it would seem to be close to the Nassau/Suffolk border or a bit east...west side of it you would see snow, east side likely rain or very wet snow as surface winds from the east or even east-southeast setup...heaviest snow usually just west of where the front sets up with rapidly declining amounts once you get even 20 miles west of it, hard to say how much given it depends on the duration of the front and how fast the system moves up the coast...looks like a good 6-10 hours though....the 12Z SSB MM5 doesn't show anything at all, I'd like to see some mesoscale models jump on it...as I said in the main thread, its rare these events happen, even when they are modeled...the only incident I recall in the region where a modeled norlun happened was on the central Jersey coast back in the 96-97 winter when they got 3-5 inches in Monmouth and Ocean counties one morning from a low that was 300 miles offshore.

[jrodd321]

I posted in the christmas threat thread also, but would it be wise after this weeks modeling inconsistency with this past storm that it would be wise to not overanalyze the models till the 96 hour or less mark? Granted the setup with this storm looks relitively "easier" than the other threat but I think just waiting till the 96 hour or less period to be getting pumped about this system would be a better approach. Would like an opinion, thank you

Not really trying to analyze the system though. Its just a good sign to see the models constantly showing a nice storm for us run after run. We can work out all the details later.

[eduggs]

I don't know if anybody will agree though with me, hopefully I can get a met response on this. This storm as being progged for 24th to 25th looks great so far and the set up with this storm looks to be "easier" compared to the last threat, but with the past models performances this week and how poor and relatively inconsistent they were wouldn't it be wise to take a step back and don't make any kind of false hopes till we get into the 96 hour or less range till the event?

I agree that this potential storm has fewer obstacles to overcome to succeed for us. The op GFS has been very consistent and today's charts look fantastic. Ensembles are also very favorable. The Euro, GGEM, UK, and Nogaps also show the storm in the same time period with a comparable setup. The spread is much narrower for this threat than the last one at the same juncture.

But I disagree that the model performance has been terrible. At least a week ago the consensus was for a developing western Atlantic cutoff with deep ocean gale. That looks to be exactly what we're getting. With the exception of a few outlier runs that developed an amplified trof and cutoff further SW, the guidance has been fairly consistent. All this during a highly anomalous period. What has been inconsistent is everyone's expectations.

[eduggs]

Beautiful run, especially for a little southwest of our area.

Nearly perfect "all-snow" track... looking at 850mb, 700mb, 500mb lows. Would be major snowstorm all the way back west through all of EPA, NWNJ, and ENY (more so than GFS QPF indicates).

[ARyan]

I don't like getting excited about a storm this far away on the GFS, or any medium range model for that fact, since it's basically trending towards climatology. But wow. It doesn't get better than that. Absolutely beautiful on all levels.

[Alpha5]

http://www.meteo.psu.edu/~gadomski/CMC_12z/cmcloop.html

Yeah.....

[isnice]

http://www.meteo.psu...2z/cmcloop.html

Yeah.....

Hah...guaranteed result.

[eduggs]

Isn't this another case where the shortwave needs to phase with the northern stream or else we just see a weak disturbance heading east and OTS? Seems like another thread the needle event where we need the confluence to be weaker and more amplification and phasing although this is more Nina-esque than the last threat. Appears to be strong miller B like system on the gfs.

Kind of. But a major difference in this case looks to be that the storm will have much more latitude initially. A problem of late is that storms take wide turns, start far south, and therefore miss us entirely.

"Miller B" is an oversimplified term. Sure, the surface center would likely redevelop somewhat from the southern Apps to the Carolina coast... but nearly all lows do this based on thermodynamic principles that are well beyond me... even storms generally classified as "miller A." In this case the primary storm traverses the country in a fairly consistent fashion with mid and upper levels lows moving together. We don't end up with a decaying primary surface or upper level low in the lakes with a secondary in the Atlantic.

[isnice]

Well the 96 storm was like this where the EURO and GFS where neck and neck a week out before it hit it was a horse race by the models.

Well, here's how you know if it's going to happen or not:

If the Euro does not show a storm hitting the coast at 12z, it won't be happening.

If the Euro shows a storm hitting the coast at 12z on Wednesday, it won't be happening.

I find it pretty comical that we have agreement once again, six days out (on a Sunday nonetheless) for a storm on Saturday-Sunday (as per the GFS). It's the same distance away lol as the one we were just tracking. If last week is any indication, I will end end up popping an anurism from stress by Wednesday afternoon.

[gkrangers]

http://www.meteo.psu...2z/cmcloop.html

Yeah.....

Only slight disagreement.

[BaltimoreWxGuy]

Well, here's how you know if it's going to happen or not:

If the Euro does not show a storm hitting the coast at 12z, it won't be happening.

If the Euro shows a storm hitting the coast at 12z on Wednesday, it won't be happening.

I find it pretty comical that we have agreement once again, six days out (on a Sunday nonetheless) for a storm on Saturday-Sunday (as per the GFS). It's the same distance away lol as the one we were just tracking. If last week is any indication, I will end end up popping an anurism from stress by Wednesday afternoon.

One thing I have to say is, this system is quite a bit different from the system occuring this weekend, the Xmas storm should be easier to handle for the models, Im not saying they are correct this far out, but we shouldnt see as much waffing, especially inside 100 hours.

[mattinpa]

GGEM overdoing the confluence? I know in a Nina year it's possible that it's correct. Any thoughts on what track seems more likely?

[tombo82685]

A coastal front would setup somewhere, if you believe the 12Z Models it would seem to be close to the Nassau/Suffolk border or a bit east...west side of it you would see snow, east side likely rain or very wet snow as surface winds from the east or even east-southeast setup...heaviest snow usually just west of where the front sets up with rapidly declining amounts once you get even 20 miles west of it, hard to say how much given it depends on the duration of the front and how fast the system moves up the coast...looks like a good 6-10 hours though....the 12Z SSB MM5 doesn't show anything at all, I'd like to see some mesoscale models jump on it...as I said in the main thread, its rare these events happen, even when they are modeled...the only incident I recall in the region where a modeled norlun happened was on the central Jersey coast back in the 96-97 winter when they got 3-5 inches in Monmouth and Ocean counties one morning from a low that was 300 miles offshore.

the euro has that look also hrs 36 n 42

[SACRUS]

GGEM overdoing the confluence? I know in a Nina year it's possible that it's correct. Any thoughts on what track seems more likely?

Too ealry to say, but the gfs and 0z ecm and uk (havent seen 12z) show the potential. Onto the ecm and watch the trends ober the next few days.

[Rainshadow]

It was Stan Wasserman who was quoted I believe...I just remembered a few other things from that list of names...Ed Yandrich if I remember correctly I read in some publication back in school during the 90s was the forecaster who issued the blizzard warning the morning of the April 1982 event and won some sort of award for it....Izzo I met at an open house once I believe, if he's the guy who had an exceptionally deep voice.....Stalker is an unforgettable name as well, I'm pretty sure anyone who watched TWC in the 80s and 90s remembers that one from the special statements I think it did snow on Long Island during that event, but I don't think it was quite warning criteria, maybe 3-4 inches?

Stan was the MIC at that time. The April 82 blizzard, I know Harold Gibson the MIC at that time was gung ho about it occurring. It was spring brake at CCNY, my senior year. I was the president of the local AMS chapter, so I had the keys to the college weather lab, remember going to College that Monday(?) with a couple of friends to turn on the fax machine to look at the lfm run.

Speaking of Norlun trofs, there was a December event, not sure when in the late 80s in which it rained on the east end of Long Island , a foot of snow in central Long Island and maybe an inch in NYC. Tom Grant wrote an apologetic special weather statement saying we busted badly that we became observers and were not forecasters with that event. He got grief for being honest.