Moving Through December - Changing Patterns and Changing Diapers

[HM]

I seem to recall last year at some point the NAO registered negative, but that was because everywhere downstream of the Alaskan vortex, from california to greenland, had above normal heights. What a winter.

The end of the 12z gfs ensembles have a healthy -NAO developing, but I agree with the skepticism given the predicted vortex state/position at that point. It is curious to me that the gfs suite would even develop this -NAO block in the long range despite really stregnthening the vortex in that vicinity. I mean, it has your "tornado" up there big time by days 10-15. Closer inspection of the height departures though shows the "tornado" swinging towards the Asian side of the pole and a +height anomaly developing from 50mb to 10mb in Greenland over that time frame... This is of course in fantasy land, but had support from the ensembles...not sure what to make of that

I see a few people here are hopeful that the cold will settle into the east by the latter stages of Dec, I'm not sure though. I would think the trend will be towards a relaxation of the -AO (not that its helping us now anyway) /a trend towards positive with the strat gathering itself after these waves. The -PDO and pacific pattern that appears to be very assertive early on this winter would probably leave the east really torching without any AO help?

Yes the GFS suite has been suggesting we squeeze the strato-vortex into Asia way out there beyond day 10, which would allow the CW to move in and create quite the convoluted troposphere below. This is all very possible but how quickly does this happen? The Tropics may also be trending away from a suitable environment mid-December and we know that wave 1 responses can take a while...but those timings are based usually on top-down type warmings.

I agree with general ideas of gradient pattern mid-month and I don't think things are bad in the North in terms of snow/ice chances. There may be another torch sometime between that pattern and the possible blocking that develops in January. But that in between time frame is tricky. The torch could be brief and remain a gradient look /SE ridge instead.

[subdude]

64 arghhhhhhhh

[HM]

Does anyone know if the ECMWF ensembles are also moving the strato-vortex into Asia beyond day 10?

[am19psu]

Does anyone know if the ECMWF ensembles are also moving the strato-vortex into Asia beyond day 10?

At 288, there is a lobe over the Bering Strait, but it dissipates in time, and the vortex moves from Hudson Bay back to the pole by 360.

[HM]

The ensemble mean is back over the pole by 360

I suppose there is some disagreement with the Aleutian High / CW then?

[#NoPoles]

64 arghhhhhhhh

poor WaWa...just when they got their snow guns cranking and getting terrain open...now they have to sit back and watch their shrinking base...and all that money melt away...

[CoastalWx]

This is what happened...

Upward flux originally occurred in eastern Europe/western Siberia which is classic wave 2 origin. Despite the warm, -EPO/WPO pattern in the northern Pacific, the stratospheric air here was cold and so was the vortex. Since we knew the troposphere / stratosphere were not jiving yet, the warm anomalies were safe and the forcing from the troposphere/ocean would sustain them, despite the cold stratosphere aloft. The upward flux from eastern Europe in combination with the -QBO and lower solar periods allowed for the amplification to upwell, forcing a squeeze play from North America into eastern Siberia.

Now that tropospheric cold has carved out over Siberia, the stratosphere is beginning to warm here from the upwelling flux and is combining with the tropospheric -WPO wave anomaly to form a huge wave 1. This is NOT a classic wave 1 where an Aleutian Low is responsible but it doesn't matter since we have the wave 1 coming (the low is displaced from usual location). Because the strato-vortex itself was so cold and strong and the wave 2 was only predicted to be modest, we knew the vortex would stay in tact. It's positioning would send it back to the North Atlantic because of the warmings from Asia, keeping it from moving there.

This whole thing happened quickly and will force the PV back to Greenland. This is why I'm warning of models with west based -NAO patterns etc. I don't think this will happen until that PV is destroyed/out of there.

Alright, nice description. You've mentioned all this before, but this is a good summary. I'm actually glad I had similar thoughts and understood what you said because it proved I picked up a thing or two after doing some research...lol.

I guess IHMO I never looked at having the vortex pushed into Greenland as a bad thing considering favorable patterns in the past have also done this....but perhaps because of the persistence of the cold vortex and its resiliency ...it makes the pattern transition in the stratosphere less than ideal. Obviously every year and every transition is different.

[dryslot]

Hey now fellow NNE'er

...the moose care....oh wait most of them are in NH and ME. So yeah you're right, lol.

Kind of a inside joke comment, But I guess you did not see some of the posts from a day or 2 ago about some thoughts of snow in NNE

[HM]

At 288, there is a lobe over the Bering Strait, but it dissipates in time, and the vortex moves from Hudson Bay back to the pole by 360.

I suppose there is some disagreement with the Aleutian High / CW then?

Didn't see the new info, thanks Adam. Very discouraging for the remainder of December then.

[subdude]

poor WaWa...just when they got their snow guns cranking and getting terrain open...now they have to sit back and watch their shrinking base...and all that money melt away...

it's sad, 5 days of snowmaking gone in one day of 60 degrees.

[HM]

Alright, nice description. You've mentioned all this before, but this is a good summary. I'm actually glad I had similar thoughts and understood what you said because it proved I picked up a thing or two after doing some research...lol.

I guess IHMO I never looked at having the vortex pushed into Greenland as a bad thing considering favorable patterns in the past have also done this....but perhaps because of the persistence of the cold vortex and its resiliency ...it makes the pattern transition in the stratosphere less than ideal. Obviously every year and every transition is different.

Like a tornado, there is usually several dancing vorticies and there smaller cyclones within larger cyclones (the tornado cyclone / mesocyclone / etc.). On a stratified surface, the main vortex area is the main zone connecting the mesosphere to the troposphere with NOx etc. If this is the vortex predicted to be over Greenland, I would be cautious about -NAO forecasts while it is there. But like anything else, the vortex will move and a warming could easily move in around it.

Every situation is different of course...so yeah...

[N. OF PIKE]

Didn't see the new info, thanks Adam. Very discouraging for the remainder of December then.

is this for MA or into boston as well.

[wxeyeNH]

Certainly not a warm day up here. Stuck in the low to mid 40's. If we are not going to have snow and cold I would rather be 60F like you guys down there!

[Mr Torchey]

Just got home for lunch and was able to open some windows to let some fresh air in, do not get to do that very often in December. People seem to be in a fabulous mood today everywhere I go, spring in there step for sure.

[N. OF PIKE]

Certainly not a warm day up here. Stuck in the low to mid 40's. If we are not going to have snow and cold I would rather be 60F like you guys down there!

the torch today was muted for CNE/NNE cept maybe coastal maine (portland-50's) . NNE mostly 30's

sne mostly 57-62 , cept for the east slope of course, but no seriously still in mid 40's at beckett, peru,savoy, and upper 40's for the elevations in NW ct

[Brian5671]

Just got home for lunch and was able to open some windows to let some fresh air in, do not get to do that very often in December. People seem to be in a fabulous mood today everywhere I go, spring in there step for sure.

do you remember last December?

[weatherMA]

Feels cool here actually. Down to 44.7/35 with gusty winds. Nice in the sun but certainly doesn't feel warm really.

Tropics down there in SNE.

[dryslot]

the torch today was muted for CNE/NNE cept maybe coastal maine (portland-50's) . NNE mostly 30's

sne mostly 57-62 , cept for the east slope of course, but no seriously still in mid 40's at beckett, peru,savoy, and upper 40's for the elevations in NW ct

We live for one more day, We will have our turn tomorrow i think before the front comes thru weds, In my avatar its only 14F here, Don't know what the f uk is up with that though

[ORH_wxman]

Massive cutter on the Euro...even west of Chicago, lol. But it ends up building a monster block in Greenland/Iceland during the Dec 11-12 period on the Euro.

[usedtobe]

This is what happened...

Upward flux originally occurred in eastern Europe/western Siberia which is classic wave 2 origin. Despite the warm, -EPO/WPO pattern in the northern Pacific, the stratospheric air here was cold and so was the vortex. Since we knew the troposphere / stratosphere were not jiving yet, the warm anomalies were safe and the forcing from the troposphere/ocean would sustain them, despite the cold stratosphere aloft. The upward flux from eastern Europe in combination with the -QBO and lower solar periods allowed for the amplification to upwell, forcing a squeeze play from North America into eastern Siberia.

Now that tropospheric cold has carved out over Siberia, the stratosphere is beginning to warm here from the upwelling flux and is combining with the tropospheric -WPO wave anomaly to form a huge wave 1. This is NOT a classic wave 1 where an Aleutian Low is responsible but it doesn't matter since we have the wave 1 coming (the low is displaced from usual location). Because the strato-vortex itself was so cold and strong and the wave 2 was only predicted to be modest, we knew the vortex would stay in tact. It's positioning would send it back to the North Atlantic because of the warmings from Asia, keeping it from moving there.

This whole thing happened quickly and will force the PV back to Greenland. This is why I'm warning of models with west based -NAO patterns etc. I don't think this will happen until that PV is destroyed/out of there.

And an east based NAO won't do us much good in the east especially south of 40N without the ridge in the Pacific getting to the coast and being a little more amplfied than shown on the D+11 mean. Those thinking the negative AO and NAO are going to cause a quick switch to colder than normal in east are probably going to be disappointed. That's not to say there won't be cold shots but they probably will not be really cold. Until the NAO positive anomaly moves west, the Pacific will be the driving force. At least that is what I'm thinking.

[N. OF PIKE]

thurs 12z looks a lot milder today than it did on yesterdays' run. not sure about a day stuck in 30's on thursday.

[easternsnowman]

This seems to be looking like a 99-2000 winter where nothing shapes up until mid- to late january, maybe the best we can hope for in these times.

[CoastalWx]

Like a tornado, there is usually several dancing vorticies and there smaller cyclones within larger cyclones (the tornado cyclone / mesocyclone / etc.). On a stratified surface, the main vortex area is the main zone connecting the mesosphere to the troposphere with NOx etc. If this is the vortex predicted to be over Greenland, I would be cautious about -NAO forecasts while it is there. But like anything else, the vortex will move and a warming could easily move in around it.

Every situation is different of course...so yeah...

Yeah I agree having the vortex overhead certainly doesn't help in the near term, I was thinking more down the road...but as we mentioned..every transition is different and you have to look at the state of the strat as currently depicted. That will also have a say as to how things develop.

[Snow_Miser]

Thoughts on the 12z ECMWF at hr 192? It doesn't look half bad from my amateur perspective:

[OSUmetstud]

ugh can't even get good les from a low cutting through Chicago.

[OKpowdah]

Just throwing this out there... What storm was it that at D9 was a GL stem winder S gale for us, then, it was a coastal blizzard, and what happened.... flat wave with paltry overrunning.

Guys - relax! you're acting like a heroine addict that's paranoid about their next fix - haha.

I know what mean though - it would be nice for entertainment's sake if you had some eye candy. Agreed. But you just gotta be stronger and more insightful than that, and you can derive almost the same value. What I mean is, the NAO is also diving, and there is a H. A. signal from that, too, not just the PNA rise - albeit not quite as impressively as 2 night ago at CPC. That's fine, as Will pointed out, the ensemble means have been a bit flippy floppy as of late, and that could effect the PNA calculation.

To me I'm still thinking an icing scenario could be on the table to enter...

This is true. Reminds me of the storm in February 2009 (?) ECMWF and GFS had a massive historic bomb over the Great Lakes around day 6-7 ... Gradually shifted east for a few runs of New England magic ... and the wave just kept getting flatter and flatter until barely anything was left. The NAM and NGM briefly brought it back around hr48-60ish before finally giving up. Ended up with some light 1-3" inverted trough business.

[Snow_Miser]

The 12z ECMWF is very transient with the cool shot that moves in after the Dec 10th storm system. Looks like a warm up after that FWIW.

[N. OF PIKE]

we should have a meltdown index for the region.

if the gradient shows more clues for wintry wx to be confined to CNE/NNE or north , we should have quite a few by 12/20.

[Damage In Tolland]

This is true. Reminds me of the storm in February 2009 (?) ECMWF and GFS had a massive historic bomb over the Great Lakes around day 6-7 ... Gradually shifted east for a few runs of New England magic ... and the wave just kept getting flatter and flatter until barely anything was left. The NAM and NGM briefly brought it back around hr48-60ish before finally giving up. Ended up with some light 1-3" inverted trough business.

Yeah that appears to be happening with the storm for early next week. A cutter west of Chi lol

[NJwinter23]

This is what happened...

Upward flux originally occurred in eastern Europe/western Siberia which is classic wave 2 origin. Despite the warm, -EPO/WPO pattern in the northern Pacific, the stratospheric air here was cold and so was the vortex. Since we knew the troposphere / stratosphere were not jiving yet, the warm anomalies were safe and the forcing from the troposphere/ocean would sustain them, despite the cold stratosphere aloft. The upward flux from eastern Europe in combination with the -QBO and lower solar periods allowed for the amplification to upwell, forcing a squeeze play from North America into eastern Siberia.

Now that tropospheric cold has carved out over Siberia, the stratosphere is beginning to warm here from the upwelling flux and is combining with the tropospheric -WPO wave anomaly to form a huge wave 1. This is NOT a classic wave 1 where an Aleutian Low is responsible but it doesn't matter since we have the wave 1 coming (the low is displaced from usual location). Because the strato-vortex itself was so cold and strong and the wave 2 was only predicted to be modest, we knew the vortex would stay in tact. It's positioning would send it back to the North Atlantic because of the warmings from Asia, keeping it from moving there.

This whole thing happened quickly and will force the PV back to Greenland. This is why I'm warning of models with west based -NAO patterns etc. I don't think this will happen until that PV is destroyed/out of there.

Great explanation. This question may not have a set answer, but when do we know/predict when the strat/trop are going to jive. For instance, during october they were not coupled as you mentioned, with the troposphere blocking running the show despite some cold strat anomalies. What tips us off that the position of the pv at 10mb/50 mb will have such a top-down effect going forward through later december? Is it the time of year, the predicted stregnthening of the vortex that tells us this?