December 2022 Medium-Long Range Disco

[clskinsfan]

Still a little early for NAM extrapolations. Damn shame. That is when this site is fun. 

[Scraff]

11 minutes ago, clskinsfan said:

Still a little early for NAM extrapolations. Damn shame. That is when this site is fun. 

Extrapolation followed by a good NAMing. Who doesn’t love that!?

[Maestrobjwa]

1 hour ago, clskinsfan said:

Still a little early for NAM extrapolations. Damn shame. That is when this site is fun. 

One of the first weenie quotations I ever saw when I found this site in Winter 2014 was: "Wam, bam, thank you NAM!" Why that sticks out to me I have no clue, but yep...that was the start of the descent into the madness 

[NorthArlington101]

Doesn’t amount to much, but the GEFS is on its way towards caving to the EPS, at least off this run. The mean shaves 2-3 degrees Celsius off everyone’s temps as the precip comes through Friday evening. Results aren’t that spectacular, but it’s a start if you are hunting for something, especially in favored spots north.

[Stormchaserchuck1]

That's not a -NAO on the 00z GFS MR

[Stormchaserchuck1]

15 minutes ago, Stormchaserchuck1 said:

That's not a -NAO on the 00z GFS MR

And what do you know, this might be a real snow threat

 

[NorthArlington101]

Doesn’t amount to much, but the GEFS is on its way towards caving to the EPS, at least off this run. The mean shaves 2-3 degrees Celsius off everyone’s temps as the precip comes through Friday evening. Results aren’t that spectacular, but it’s a start if you are hunting for something, especially in favored spots north.

For the 2 people interested, the GEPS turned on the toaster. I’m not even interested enough to wait for the EURO unless I’m accidentally awake in an hour.

[Weather Will]

WB OZ PNA teleconnection EPS and GEFS.  We will know by the end of next weekend if the EPS can deliver…

[CAPE]

The bottom line is having a mechanism for delivery of anomalous cold, especially in December. The currently advertised pattern on the EPS would get it done, as would the CMC ens(actually looks unrealistically cold given the h5 look). EPS has the best/coldest look at h5 with a -EPO/slightly +PNA from mid month onward. GEFS has improved in recent runs, but doesn't quite get the NPAC sorted- has a slightly -EPO/neutral PNA look towards D15.

Root for the EPS, although as @WxUSAF said, the pattern progression it has been depicting looks more Nino than Nina, and it has trended towards the GEFS in recent weeks moving from the LR to MR.

 

[aldie 22]

Looks like my 70 call will fail for the 7th....but 12/19 looks like our next shot at 70

[Weather Will]

3 minutes ago, leesburg 04 said:

Looks like my 70 call will fail for the 7th....but 12/19 looks like our next shot at 70

Not according to WB 6Z GEFS…

[aldie 22]

12 minutes ago, Weather Will said:

Not according to WB 6Z GEFS…

Maybe it's just delayed

[nj2va]

6z GEFS continues to look different than the EPS in the LR.  

This is super LR so take with a grain of salt but here’s the trend of the last 4 runs. 

ETA:  Meant to add that I'd like to see the GEFS not correcting to a less favorable PNA which seems to be the case based on the evolution above.

[psuhoffman]

1 hour ago, leesburg 04 said:

Looks like my 70 call will fail for the 7th....but 12/19 looks like our next shot at 70

delayed but not denied  

[CAPE]

I just took a quick look at the Pacific basin on the means, centered around the 20th of Dec. Indication of more precip(convection) in the Western Pac on the EPS and GEPS, with not much going on in that region on the GEFS. The N Pacific Jet configuration on the EPS and GEPS is notably more extended than on the GEFS to my eye. This explains at least in part the differences  we are seeing in the advertised h5 patterns. The base state in a Nina is usually hostile to our goals, so it's always a fight. The other problem with the latest GEFS runs is the -NAO looks a bit wonky and weaker, and if that is close to reality it won't do much to mitigate an unfavorable Pacific.

[mappy]

If it snows around 12/19, I am taking credit just because. 

[CAPE]

Fwiw the GEFSX does get the h5 pattern very close to the look on the EPS, but later. Delayed not denied.

[poolz1]

22 minutes ago, CAPE said:

I just took a quick look at the Pacific basin on the means, centered around the 20th of Dec. Indication of more precip(convection) in the Western Pac on the EPS and GEPS, with not much going on in that region on the GEFS. The N Pacific Jet configuration on the EPS and GEPS is notably more extended than on the GEFS to my eye. This explains at least in part the differences  we are seeing in the advertised h5 patterns. The base state in a Nina is usually hostile to our goals, so it's always a fight. The other problem with the latest GEFS runs is the -NAO looks wonky and weaker, and if that is close to reality it won't do much to mitigate an unfavorable Pacific.

I know the RMM plots don't necessarily tell the whole picture but interesting that the GEFS pretty much went all in on the MJO reemerging into 1,2.  Curious if todays runs start to shift to a colder outcome in the LR.  

[CAPE]

Just now, poolz1 said:

I know the RMM plots don't necessarily tell the whole picture but interesting that the GEFS pretty much went all in on the MJO reemerging into 1,2.  Curious if todays runs start to shift to a colder outcome in the LR.  

I just looked at that. It might. In general the forcing looks weak regardless of phase. Not an expert on that stuff but that's gotta be better than having persistent convection near the MC.

[midatlanticweather]

The winter of ever delays! It feels like this may the case.

How about the 45 day Snow outlook.. I think maybe something is showing up on this in the southeast! We get that Nina split too! Painful. Reminds me or 2010 - 2011 season

[psuhoffman]

@CAPE unfortunately we've been seeing a lot of what we typically get in a long range pattern fail.  Over the last 5 years guidance has often teased the progression of the pacific when in reality it quickly retrogrades into its hostile base state, or fails to ever even get out of it.  One troubling feature, even on the better looking long range guidance, the central pacific ridge is still healthy and centered exactly where we don't want it.  The EPS at times is getting a good look by extending that ridge all the way into western N American and even at times linking with the AO/NAO.  But that's just tenuous at best and unlikely a sustainable longwave pattern.   So long as the main heat transfer in the pacific continues happening north of Hawaii we are going to have a really difficult time getting true cold air and fighting off a SE ridge.  

The other issue is that the NAO isn't a true block.  The actual block there now was originally supposed to retrograde to Baffin.  Instead the "block" is being squezed out and what we end up with is simply higher heights up top mostly due to the fact there is no cold air anywhere on our side after the TPV slides out.  The higher heights we see up top is mostly a useless feature in terms of doing us any good wrt a pattern favorable for snowfall.  

On the positive side, things could be much worse.  The amplitude of the pacific ridge is not as great as it was during some of our worse periods.  There is no blue ball of death up top.  The pattern is close enough that it could still evolve towards a better place down the road, even if I am skeptical.  Problem is...the pattern being "ok" doesn't really do us any good anymore most of the time.  As I was lamenting with @WxUSAFthe other day, we don't really luck our way to snow in marginal setups very often anymore.  We really need a true cold air source and favorable pattern to get snow.  

[North Balti Zen]

I see "the claw" lurking...

[psuhoffman]

18 minutes ago, CAPE said:

I just looked at that. It might. In general the forcing looks weak regardless of phase. Not an expert on that stuff but that's gotta be better than having persistent convection near the MC.

I few years ago I hypothesized based on observation that the MJO impact is most significant when it is in phase and conjunction with the base state and often has little impact when its weak and out of phase with the base state.  For example...a strong phase 8-1 during el nino will initiate a great pattern.  But when we were waiting all winter for the MJO to weakly meander into phase 8 during a Nina...when it did finally do so it had no real impact other then to make the pattern perhaps a little less awful for a week.  

[CAPE]

45 minutes ago, psuhoffman said:

@CAPE unfortunately we've been seeing a lot of what we typically get in a long range pattern fail.  Over the last 5 years guidance has often teased the progression of the pacific when in reality it quickly retrogrades into its hostile base state, or fails to ever even get out of it.  One troubling feature, even on the better looking long range guidance, the central pacific ridge is still healthy and centered exactly where we don't want it.  The EPS at times is getting a good look by extending that ridge all the way into western N American and even at times linking with the AO/NAO.  But that's just tenuous at best and unlikely a sustainable longwave pattern.   So long as the main heat transfer in the pacific continues happening north of Hawaii we are going to have a really difficult time getting true cold air and fighting off a SE ridge.  

The other issue is that the NAO isn't a true block.  The actual block there now was originally supposed to retrograde to Baffin.  Instead the "block" is being squezed out and what we end up with is simply higher heights up top mostly due to the fact there is no cold air anywhere on our side after the TPV slides out.  The higher heights we see up top is mostly a useless feature in terms of doing us any good wrt a pattern favorable for snowfall.  

On the positive side, things could be much worse.  The amplitude of the pacific ridge is not as great as it was during some of our worse periods.  There is no blue ball of death up top.  The pattern is close enough that it could still evolve towards a better place down the road, even if I am skeptical.  Problem is...the pattern being "ok" doesn't really do us any good anymore most of the time.  As I was lamenting with @WxUSAFthe other day, we don't really luck our way to snow in marginal setups very often anymore.  We really need a true cold air source and favorable pattern to get snow.  

The Pacific is always a battle, but I also don't like the look of the NAO on the latest runs. It seems to evolve from a full lat ridge resulting from the western trough, then it tilts neg into GL, but it isn't so much a ridge at that point as it is a blob of higher +heights sitting there. Looking at the height lines they look flat, with little indication of a true -NAO dipole as we were seeing on previous runs, and ofc the TPV has exited stage left. As for getting legit cold air, I think it will probably have to come from a -EPO period..

[Maestrobjwa]

1 hour ago, mappy said:

If it snows around 12/19, I am taking credit just because. 

You might have to share credit with Avatar 2 

[frd]

25 minutes ago, psuhoffman said:

One troubling feature, even on the better looking long range guidance, the central pacific ridge is still healthy and centered exactly where we don't want it.  The EPS at times is getting a good look by extending that ridge all the way into western N American and even at times linking with the AO/NAO.  But that's just tenuous at best and unlikely a sustainable longwave pattern. 

Several thoughts -  the impact later in a season when the Nina starts to weaken, and if so, the Pac might improve in Feb to March, even though most Ninas are front loaded  in our area cold and snow-wise.  

Also, we are nearing the potential for a - 4 SD AO.  Implications for another - AO regime later in the winter seems a higher probability. 

Snow cover, during the past 5 years NH snow cover has been very impressive. many thought with such a wide expanse of snow cover over the NH and especially over North America it would increase the odds of a cold Jan the last few years. But, what evolved the last few years is around mid December most of the North America snow cover was reduced drastically during a turn to warmer conditions accompanied by a - PNA, + AO,  + NAO regime.  History may not repeat this December to the degree of the last few Decembers. 

If we can keep the snow cover and repeat in Jan with a - EPO reload / - AO / - NAO we might score .  However,  we still need the Pac to improve somewhat, at  least for a short window of time.  Even the end of this month may exhibit a short window for snowfall. 

 

[frd]

The Pac can not get modeled correctly.  Or,  what psu said.  Don't assume any colder scenarios until inside day 7 . 

However,  there have been looks such as the trough in the West with mild air over the East that did have change rapidly in a week's time leading to  East Coast snow. 

 

 

[poolz1]

I don't know if saying the can is being kicked or things are "delayed" is correct?  I mean, losing the TPV rolling under the block to SE Can and becoming a stable 50/50 feature forced the whole pattern to take on a different look.  That TPV was the original catalyst for cold mid and low level flow and would be in place right now.  We are now required to manufacture our own beast of a 50/50 or wait for the PAC to cooperate.  This is different from modeling being slow on the cold press and things are just taking their time evolving.  

[CAPE]

I have said this before, but in recent ENSO neutral/Nina/weak ass Nino winters, since 2016, the -NAO periods(mostly bootleg) have generally been too marginal (with stale/ Pacific origin cold) to get it to snow in the MA lowlands. Best outcomes have been in more progressive patterns during periods where the PAC was more favorable, mostly -EPO, with real deal cold air delivery. More of a thread the needle situation but it seems to work out better esp in a Nina. Need cold first! HL blocking during a CP moderate Nino has been gold- maybe we get that combo next winter, and we can see if that still works.

[WxUSAF]

11 minutes ago, poolz1 said:

I don't know if saying the can is being kicked or things are "delayed" is correct?  I mean, losing the TPV rolling under the block to SE Can and becoming a stable 50/50 feature forced the whole pattern to take on a different look.  That TPV was the original catalyst for cold mid and low level flow and would be in place right now.  We are now required to manufacture our own beast of a 50/50 or wait for the PAC to cooperate.  This is different from modeling being slow on the cold press and things are just taking their time evolving.  

Bingo