Rising confidence in favorable period for snow Dec 15 - Jan 1

[alwaysready126]

Sorry but there are no guarantees. If we get one good (3-6") snowstorm consider it a win

Didnt say it was guaranteed,  

[Isotherm]

I do quite enjoy when patterns progress as planned...

 

This December should turn out fairly close to the analog package analyzed w/ the tendency for coolness to persist near the SE US coast, and I continue to like the idea of a near normal finish for December in our neck of the woods. Surface highs continue to mute the warm-up in the short to medium range for the Northeastern US; however, I do believe there's liable to be a transient burst of above / well above normal air prior to the pattern reshuffling. This warm-up climax should occur around the mid point of December.

 

 

December Analogs (the JF composite is certainly much different looking):

 

 

 

 

The much discussed NW Asian low is now poised to propagate southeastward, such that a mid level ridge will take its place, and eventually burgeon northeastward across Siberia. Thus, I anticipate the long-wave tropospheric pattern will become increasingly conducive for the resumption of vertical wave driving, particularly in the D7-15 period. While the 10mn vortex remains tight / strong, an upwelling of warmth should occur D5-10 inducing a potential wave 2 / split opportunity at 100mb-70mb. At this point it appears the stratospheric vortex should tilt in such a way that it becomes more susceptible to WAF, although I'm not sure this upcoming attempt will succeed in producing a SSW. It'll probably be third time's the charm: we attack the vortex yet again later this month, and the real tanking of the AO follows suit. The progression seems similar to years like 1979 and 2003 in terms of reversal timing in AO modality and SSW potential. Mentioned those two years quite a bit and think they're reasonable analogs going forward.

 

Both the GFS and ECMWF depict wave 2 potential in about a week to 10 days.

 

 

 

 

 

 

 

 

 

 

Meanwhile, tropospherically, the pattern will be progressing in such a way that's in sync with +ENSO.

 

Look for the following to occur in the next 2 weeks:

 

 

[1] The Mid level ridging over Siberia and North America will eventually propagate northward and connect over the Arctic Circl

 

[2] The Siberian ridge will induce the formation of a trough downstream over the N PAC / NE Asia.

 

[3] Retrogression of Eastern Gulf of Alaska troughing into the Aleutians, more in line w/ the current SSTA profile, and in agreement with +PDO / +ENSO forcing.

 

[4] The development of a negative EPO and negative AO by the final 10 days of the month, especially the final week. The NAO will likely to last to follow suit, but the evidence is strong for a spread of higher heights in the NAO regime by the end of December/early January. -QBO forcing will keep the stratospheric vortex perturbed and warmer than normal through the next 3 weeks, regardless of SSW timing.

 

 

 

One can see the aforementioned pattern progression on the ECMWF weeklies, and by the end of December / New Year's, the NAO is negative as well. Mid latitude ridges should connect over the pole.

 

[Isotherm]

JMA has the retrogression as well w/ a -EPO developing by week 3 and the split flow look (don't break your neck):

 

[PB GFI]

JMA has the retrogression as well w/ a -EPO developing by week 3 and the split flow look (don't break your neck):

Yeh once to day 14 on the Euro ensembles you can see the trough cutting underneath a positive PNA and the ridge is getting your near Hudson bay.

That s a palatable look.

[stadiumwave]

Mjo is not looking that hot the European model has it going into the circle death and then heading towards stage four

No worries with MJO with impulse that weak.

[NEG NAO]

Mjo is not looking that hot the European model has it going into the circle death and then heading towards stage four

Like I posted earlier - go do some research and see how many HECS we have had with that MJO in the COD - will surprise you - I listed 2 storms earlier

[Absolute Humidity]

One may look at MJO forcing inside the COD as neutral, may necessarily help us but it won't hurt either.

[SnowGoose69]

The GFS has backed off a bit on the crazy ridge out west Day 13-16...not surprising as models tend to want to jump on pattern changes slightly early...several ensembles are still very -EPO happy though after Day 13.

[thunderbolt]

Like I posted earlier - go do some research and see how many HECS we have had with that MJO in the COD - will surprise you - I listed 2 storms earlier

what the hell you talking about I never question your answer go back and check on the times!

[Plow driver]

GFS says winter begins on the 20th. -EPO trying to develop.

[PB GFI]

The current system probably changes back to snow all the way to the coast . The LHV is no longer the wash out once thought . For the City the latitude where this truly retrogrades will determine if it`s just some white rain or an inch or so when all is said and done .

For me it`s irrelevant as the real show with this system will be the east facing slopes from NEPA through the Catskills , the Berks and into the Green and Whites . Someone could pick up a YARD .

 

But the ensembles are starting to catch a system next week ( just in the middle of when it was suppose to be our " warm up ) .

So that needs to be watched .Then finally as I said yesterday I like how the ensembles are shaping up from the 21st  ish onward , Just in time for Christmas .

 

So if/when we miss this one , this would make it irrelevant  IMHO .

[REDMK6GLI]

The current system probably changes back to snow all the way to the coast . The LHV is no longer the wash out once thought . For the City the latitude where this truly retrogrades will determine if it`s just some white rain or an inch or so when all is said and done .

For me it`s irrelevant as the real show with this system will be the east facing slopes from NEPA through the Catskills , the Berks and into the Green and Whites . Someone could pick up a YARD .

But the ensembles are starting to catch a system next week ( just in the middle of when it was suppose to be our " warm up ) .

So that needs to be watched .Then finally as I said yesterday I like how the ensembles are shaping up from the 21st ish onward , Just in time for Christmas .

So if/when we miss this one , this would make it irrelevant IMHO .

Ever since i started seeing the time period for the pattern change back to cold and snow for the EC. The christmas week was a great time period to get a nice storm to get it started. That said IMO, best chance in years for a white christmas for a large part of the eastern US. From christmas week on it certainly looks stormy and cold just in time for our historically best time for winter storms during our winter season paul

[EasternLI]

Not bad.......not bad at all. 

[Isotherm]

Recently, we had a solar flux spike and enhanced geomagnetic activity. While still very low in the means, the transient spikes of solar wind over the past couple weeks likely could have aided in preventing the early splitting / displacement of the stratospheric vortex via November's high poleward heat flux. In a completely quiet solar environment, we probably would have seen the early season SSW ala 1981 / 1996 / 2009. However, I think the heightened solar wind over recent 7-10 day period has aided in tightening the stratospheric vortex a bit, which apparently was sufficient in the causing a "fail" in the attempt.

 

Regardless, this merely delays the arrival of a SSW, and eventually that should occur by early January. We were quite quiet in November, but December looks to have a spike in solar variance, which is slowing the process of vortex splitting.

 

[Isotherm]

And something else to consider -- a potential concern with the early SSW events and vortex split is that there's sufficient time for a re-tightening of the vortex prior to the end of winter. Case in point, in two of those early season warming events: 1981 and 1996, the AO was negative for Dec/Jan, but then moderate to strongly positive for February. So in other words, in most cases, we're going to "lose" time on one end or the other. Exceptions include years like 2009-10 which featured a perfect recipe for successive SSW events within a backdrop of very low solar / -QBO / +ENSO.

[Weathergun]

Recently, we had a solar flux spike and enhanced geomagnetic activity. While still very low in the means, the transient spikes of solar wind over the past couple weeks likely could have aided in preventing the early splitting / displacement of the stratospheric vortex via November's high poleward heat flux. In a completely quiet solar environment, we probably would have seen the early season SSW ala 1981 / 1996 / 2009. However, I think the heightened solar wind over recent 7-10 day period has aided in tightening the stratospheric vortex a bit, which apparently was sufficient in the causing a "fail" in the attempt.

 

Regardless, this merely delays the arrival of a SSW, and eventually that should occur by early January. We were quite quiet in November, but December looks to have a spike in solar variance, which is slowing the process of vortex splitting.

 

Also the -QBO didn't weaken in November, as much as was anticipated.

[PB GFI]

I wrote this AM the Euro ensembles cluster a system around the 18th off the EC .

Todays 12z Euro show another trough slipping through the lakes by the 17th and keeps the warm up to roughly 3 days .

 

In it`s today OP at Day 10 it takes the potential 18th system into the GOM and should take it up the east coast and no the lakes.

It`s further S than the GFS as the GFS is missing another trough slipping into the NE .

 

Something to keep and eye on .

[REDMK6GLI]

I wrote this AM the Euro ensembles cluster a system around the 18th off the EC .

Todays 12z Euro show another trough slipping through the lakes by the 17th and keeps the warm up to roughly 3 days .

 

In it`s today OP at Day 10 it takes the potential 18th system into the GOM and should take it up the east coast and no the lakes.

It`s further S than the GFS as the GFS is missing another trough slipping into the NE .

 

Something to keep and eye on .

im sticking to my guns paul and saying its a good chance a big chunk of the NE including coastal locals get their first white Christmas in many years. that dec.18th time period and on looks pretty promising. more so, the past several days on the LR models

[PB GFI]

im sticking to my guns paul and saying its a good chance a big chunk of the NE including coastal locals get their first white Christmas in many years. that dec.18th time period and on looks pretty promising. more so, the past several days on the LR models

CPA NEPA CNY thru all of NNE already lock in a white xmas after Tues as they never warm up.

For us the trough takes up residence here after day 11.

Snow is always a dice roll but that pattern would definitely be what you want to see for it.

[bluewave]

CPA NEPA CNY thru all of NNE already lock in a white xmas after Tues as they never warm up.

For us the trough takes up residence here after day 11.

Snow is always a dice roll but that pattern would definitely be what you want to see for it.

 

We'll probably have to be patient since it will take time for Canada to cool off again. There won't be much

cold available for the trough stuck underneath over the Northeast like we are seeing this week until

we can tap some of that Siberian. We traded the milder weather that was in the 6-10 day for

a stale cold trough this week. But maybe by the 24-31st there will be enough cold for at least

a light to moderate event all the way to the coast.

 

[PB GFI]

We'll probably have to be patient since it will take time for Canada to cool off again. There won't be much

cold available for the trough stuck underneath over the Northeast like we are seeing this week until

we can tap some of that Siberian. We traded the milder weather that was in the 6-10 day for

a stale cold trough this week. But maybe by the 24-31st there will be enough cold for at least

a light to moderate event all the way to the coast.

gfs-ens_T2ma5d_nhem_2.png

Yeh I think the area has to expect a step down and not think we flip a switch into the abyss .

The mute was a small victory . But stale Canadian cold air is still cold enough to snow with the right set up.

When u stick a trough on the EC with a Pos PNA and the center of those height rises working towards the west shore of Hudson bay you can snow .

And IMO we should

[REDMK6GLI]

Yeh I think the area has to expect a step down and not think we flip a switch into the abyss .

The mute was a small victory . But stale Canadian cold air is still cold enough to snow with the right set up.

When u stick a trough on the EC with a Pos PNA and the center of those height rises working towards the west shore of Hudson bay you can snow .

And IMO we should

Honestly with those factors you've stated a deepening storm over the BM christmas week would yield snow all the way to the coast. Doesnt have to be a "nuke bomb" like this weeks storm. I just feel we get a snow event christmas week with the setup especially height rises around the hudson bay region which is crucial for our EC storms with a lack of blocking or weak blocking

[PB GFI]

Honestly with those factors you've stated a deepening storm over the BM christmas week would yield snow all the way to the coast. Doesnt have to be a "nuke bomb" like this weeks storm. I just feel we get a snow event christmas week with the setup especially height rises around the hudson bay region which is crucial for our EC storms with a lack of blocking or weak blocking

We can snow without blocking . Something transient. Perfect ridge axis. Just enough of just enough.

It doesn't yield the bomb everyone hopes for but it's not an awful set up once past the 20th.

You never know for sure if it's Gona snow from a distance but an ok pattern could at least make things interesting the last 10 days of the month.

[bluewave]

Yeh I think the area has to expect a step down and not think we flip a switch into the abyss .

The mute was a small victory . But stale Canadian cold air is still cold enough to snow with the right set up.

When u stick a trough on the EC with a Pos PNA and the center of those height rises working towards the west shore of Hudson bay you can snow .

And IMO we should

 

Yeah, the kind of snow event you would see without true Arctic into SE Canada would probably feature p-type issues at the

coast but really favor interior sections. But it will be interesting to see if we can get nickeled and dimed enough

late month to hit the average 4.8" at NYC for December.

[stadiumwave]

A must read:

http://weather.kopn.org/wp/?p=1405

About winter storm before Christmas Joe says:

"I am looking at a Trinidad Low forming with a transfer to the coast spreading the wealth."

http://forums.accuweather.com/index.php?showtopic=31414&st=1380&start=1380

[REDMK6GLI]

Allan Huffman loves a pattern change by the 20

Many more people will be getting more excited about that time period and on. Who knows a white christmas and ring in the new year with a bang too? Hard not to get pumped right now. I would be beyond shocked if NYC made it out of this month without atleast 6" of snow anthony. Trying to keep the weenie in me from coming out but the El Nino winter is almost acting according to text book loading up for end of december into january

[MJO812]

He is calling for a very cold January

[EasternLI]

Ensembles are looking nice (Euro + GEFS), better pattern on the long range, but it's not moving back in time this time. Looks like its beginning around the 20th. Might be a good call

[Monmouth_County_Jacpot]

A must read:

http://weather.kopn.org/wp/?p=1405

About winter storm before Christmas Joe says:

"I am looking at a Trinidad Low forming with a transfer to the coast spreading the wealth."

http://forums.accuweather.com/index.php?showtopic=31414&st=1380&start=1380

here is the link to which snow88 was referring to

[SnoSki14]

Ensembles are looking nice (Euro + GEFS), better pattern on the long range, but it's not moving back in time this time. Looks like its beginning around the 20th. Might be a good call

I'm still uncertain if the changes are completed by Xmas but they should be shortly after though with no help from the NAO. The EPO will be our main contributor and then the PNA.