NYC/PHL 12/21-12/22 Threat

[SnowGoose69]

Note some similarities to the pattern at 500mb on 01/05 the day before the event...this one shears out severely as well as it comes across the Oh Valley and Midwest but still produced 4-7 inches...note with the NAO likely being positive how it really takes on a more ENE movement as it comes east too....this event would likely be forced more south.

http://www.meteo.psu.edu/~gadomski/NARR/1989/us0105.php

http://www.meteo.psu.edu/~gadomski/NARR/1989/us0106.php

[winterwx21]

What's great is that although the Pacific energy entered the US much earlier than the 18z run did, it still resulted in a great snowstorm.

I think that goes to show that this event isn't necessarily about very intricate timing, but more-so about things that are straight-forward, like how much a shortwave can amplify. Given the fact that we actually do have ridging out west, and not over-bearing confluence initially, there is room for amplification, here.

It appears to be a better setup than what we have for the storm that's about to miss us. But at 7 days out, we should all probably do ourselves a favor and not put too much energy into it the next couple days. We've seen every threat at this range fall apart so far this winter, so I'll wait until it's in closer range before putting a lot of time into it.

Even though it looks like a potential better setup for next weekend, the overall pattern this December stinks. In a La Nina we know it's incredibly difficult to get a Miller A, so you look for clipper-like events and possibilities of those systems developing into Miller Bs. But the blocking is so strong this December that those types of systems often get crushed to the south. La Nina + strong blocking makes it very difficult to get snow around here. Hopefully the next threat won't get squashed to the south, but it's certainly a possibility in this pattern.

[A-L-E-X]

Old wives' tale. Depends on the synoptics. Sometimes, it happens perfectly and the storms do set each other up, but sometimes, they completely break the favorable pattern down.

I dont think its necessarily three, but Ive heard its usually the last storm in the pattern being the strongest and also breaking the pattern down.

[SnoSki14]

The NAO should be less negative by Christmas but any threat at this point is a total crap shoot. Until it shows a threat in less than 72 hours, I'm not biting again only to be completely fooled once again.

[Collegestudent11]

Anyone doing the Euro for the 12/19, or the clipper or 12/25?

[tombo82685]

Anyone doing the Euro for the 12/19, or the clipper or 12/25?

yes, i will let you guys know what happens and tim and john will probably chime in to

[BaltimoreWxGuy]

The NAO should be less negative by Christmas but any threat at this point is a total crap shoot. Until it shows a threat in less than 72 hours, I'm not biting again only to be completely fooled once again.

Not that I blame you, but this particular system SHOULD be easier to handle for the models specifiaclly under 100 hours as its a west to east system, not nearly as many S/W's to deal with either, lets see how it plays out

[SBUWX23]

yes, i will let you guys know what happens and tim and john will probably chime in to

Do you mind telling me where you get your Euro data and how much it costs?

[tombo82685]

Do you mind telling me where you get your Euro data and how much it costs?

yea, i PM'ed you

[Collegestudent11]

yes, i will let you guys know what happens and tim and john will probably chime in to

Thank you, and i have to ask what your icon is. It is quite perplexing to figure it out.

[jm1220]

I don't think there is much precedent for this kind of pattern since maybe the 1960s. The NAO is probably entering an overall decadal negative phase while the PDO is in an obviously negative decadal phase. It's hard for models and mets to understand it since it hasn't occurred in so long. I would have to think that this is far better than the 2007-2008 pattern (which was still at least bearable for NYC) with a +NAO most of the time, but it's still hard to find a recent precedent to what we're seeing now. I have to think that eventually the lake cutter pattern reasserts itself, but we can only hope that the Greenland Block does enough damage to keep us in cold enough air for wintry precip.

[Allsnow]

I don't think there is much precedent for this kind of pattern since maybe the 1960s. The NAO is probably entering an overall decadal negative phase while the PDO is in an obviously negative decadal phase. It's hard for models and mets to understand it since it hasn't occurred in so long. I would have to think that this is far better than the 2007-2008 pattern (which was still at least bearable for NYC) with a +NAO most of the time, but it's still hard to find a recent precedent to what we're seeing now. I have to think that eventually the lake cutter pattern reasserts itself, but we can only hope that the Greenland Block does enough damage to keep us in cold enough air for wintry precip.

Yeah this blocking that is occuring this year so far i believe will be talk about in a book or class one day....pretty impressive

[hazwoper]

Thank you, and i have to ask what your icon is. It is quite perplexing to figure it out.

His avi?

You're kidding, right?

[jm1220]

Yeah this blocking that is occuring this year so far i believe will be talk about in a book or class one day....pretty impressive

I'm sure that it will have to break down sooner or later and initiate us into another familiar lake cutter/lame SW flow regime, but I would hope that it could at least help us once in a while to get some good storms that have to cutoff/amplify well south of where they would ordinarily would in a Nina regime. I still think that if this random Gulf wave didn't appear at the last minute that this storm would be MUCH better for us given the overall 500mb pattern. This has to result in something beneficial for most of us, before too long. The 1960s was a pretty good decade for NYC winters. It has to replicate itself somehow since the same pattern seems to be reasserting this year.

[Allsnow]

The 00z euro so far is alot further north with the clipper and the confluence has back off greatly...also ocean strom is exiting stage right

[HSNN4]

Wouldn't that be one heck of a consolation prize especially what we all went through with the non event all this week, Who doesn't love a true white christmas with snow falling on Christmas Eve and on Christmas day. On a personal note this would be my reward for putting up with watching The Weather Channel and News 12 NJ Weather all year long.

[A-L-E-X]

I'm sure that it will have to break down sooner or later and initiate us into another familiar lake cutter/lame SW flow regime, but I would hope that it could at least help us once in a while to get some good storms that have to cutoff/amplify well south of where they would ordinarily would in a Nina regime. I still think that if this random Gulf wave didn't appear at the last minute that this storm would be MUCH better for us given the overall 500mb pattern. This has to result in something beneficial for most of us, before too long. The 1960s was a pretty good decade for NYC winters. It has to replicate itself somehow since the same pattern seems to be reasserting this year.

You know, as we've said before, if this was a weak nina this would easily have been a 66-67 / 95-96 style winter. Easily.

[Allsnow]

hr 108 light snow is about to enter phl.....we made improvements this run for the clipper.....but then the pv drops over the lakes and starts to weaken it......

hr 114 it goes bye bye...norlun feature into boston

[tombo82685]

hr 108 light snow is about to enter phl.....we made improvements this run for the clipper.....but then the pv drops over the lakes and starts to weaken it......

im not sure if this could weaken or squash hgts, but i wonder if the norlune signature going into sne and maine is aiding to something.

[tombo82685]

hr 120 has norlun in sne, lgt precip is on nyc's doorstep

[Collegestudent11]

I honestly do not know what his picture is.

[tombo82685]

the norlun feature croaks at hr 126, so the lgt precip is gone for the nyc area

[nzucker]

You know, as we've said before, if this was a weak nina this would easily have been a 66-67 / 95-96 style winter. Easily.

I think we need the confluence to back off slightly without totally breaking down; we want to have a -NAO in a Niña so that storms don't cut northwest of us and we see more high pressure nosing down from Southeast Canada. However, the extreme level and southerly placement of the current blocking regime means that an ULL is sitting over Maine/Canadian Maritimes and preventing storms from amplifying: we've seen this with the 12/5 clipper, the 12/16 overrunning event, and with the clipper modeled for next week. All of these events are being crushed by the dominant ULL that refuses to move out. If the NAO block were like -1SD/-2SD instead of -4SD, and it moved a bit farther north, we'd have a better chance.

[Allsnow]

.50 for boston on this run

[hazwoper]

I honestly do not know what his picture is.

From the classic Rudolph the Red Nose Reindeer special. The Abominable Snow Monster of the North.

[tombo82685]

hr 144 has a sub 1004 low over the plains precip breaking out over plains

[A-L-E-X]

From the classic Rudolph the Red Nose Reindeer special. The Abominable Snow Monster of the North.

It was a classic huh. Lol, I never saw it or heard of it before now. But that picture did look like a Yeti lol.

[tombo82685]

santa is on his sleigh gathering presents at hr 150

[Allsnow]

just surface verbatiam at hr 150 looks alot like the gfs for the xmass storm....

[earthlight]

Euro has the shortwave at 150...a bit stronger with the confluence than the GFS but the surface low is in a similar spot and the precipitation field looks good so far. Let's see if it can trend better here.

All of the guidance now has the potential..so I think it's safe to say we have something to watch here.