Re: Long Range Thread 29.0

[rb924119]

We’re entering our first stretch of colder than normal weather for this season. And it will be here to stay for the next 7-9 days in part from an active MJO wave that is currently in phase 4 and heading into phase 5. This is shown to amplify the west coast ridge (+PNA) and keep the cold locked into the eastern US. Check out the Euro Ensembles 500mb Day 6-9 averages map.



The downsides I see are our trough axis and lack of NAO blocking. One trend I’m seeing in the medium to long range is that while the cold is here, the threat for storms is not as obvious because of the +NAO and progressive northern jet. The multiple waves of northern energy are not diving deep enough into the central/eastern CONUS despite the west coast ridging. One potential system catching my attention is shown between December 8th and 10th on current guidance. We could see some pseudo NAO blocking develop which is enough to slow the jet down and promote a more favorably positioned trough. So, let’s see if we’re able to get something come together because I do think come the middle of December we are likely going to get milder again (the MJO wave likely gets into the warm phases unless it dies off before it does).

Good post, Frank, although I'm going to respectfully disagree with the following:

"The downsides I see are our trough axis and lack of NAO blocking. One trend I’m seeing in the medium to long range is that while the cold is here, the threat for storms is not as obvious because of the +NAO and progressive northern jet. The multiple waves of northern energy are not diving deep enough into the central/eastern CONUS despite the west coast ridging."

I think verbatim you're right, but reading the tea leaves a bit I think reveals that your second thought regarding the potential for the pseudo NAO blocking is more accurate. What I think the models are currently having issues resolving is the response of southern tier of the western Atlantic domain. There's going to be a 50/50 low initially that looks to drift southeastward, which should result in height rises to its north. Simultaneously, we should see our storm of interest taking shape across the central U.S. as one piece of energy dives down the eastern flank of the ridge while another piece is ejecting out from the Southwest. As those phase, the long-wave trough is going to be forced to elongate and amplify, but in response to this AND the southeastward drift of the 50/50 low, height rises should* effectively pinch that southern lobe off from the main long-wave trough, resulting in a classic bowling ball closed mid-level low swinging through the interior Southeast with positive height anomalies arching over the top. Will it be classified as a technical -NAO? maybe, maybe not - statistics are a funny thing. But effectively, I think it should still function as one.

What is your observation as to why we're seeing so much pacific energy being held back in the SW CONUS? Is it just a function of the continuous retrograding and amplification of the PNA ridge to the north? Something about the pattern aloft does not feel quite right. Whether it's the split-flow look over the western U.S. or the positively tilted trough over the eastern U.S. I'm not so sure.
DEC 5th



DEC 8th



DEC 9th

Thinking more about your lead question, Frank, as I was drifting off to sleep while pondering my place and purpose in this universe, the true meaning of life, and a myriad of other questions that have baffled many a theologian (LOL), I came up with a hypothesis:

I wonder if the “drag” on the southwestern energy is manifested by upstream easterly or northeasterly flow coming across the Rockies behind the trough axis? In theory, that air is being driven to ascend, but because it’s ascending upstream of the trough axis, it acts “re-center” the base of the trough (thinking in terms of height anomalies). So instead of having a nice uniform trough that propagates smoothly over the Rockies and makes the bend, that trough base starts to distend and get distorted upstream. Given enough time, cold air keeps getting forced to rise over the Rockies upstream from the original trough axis on the easterly or northeasterly flow, which further cools it and continues to deepen the trough. The feedback continues, and as it does, that distorted trough re-centers further west with the new height field minimum, establishes a new trough axis, which then reorients the downstream height field enough to start redirecting some height falls BACK toward the Rockies. Continue this process, and consider that it’s occurring on the eastern flank of an anti-cyclonically breaking ridge (ridge folds over clockwise), which adds further easterly momentum flux beneath it, and that’s how you effectively trap the southwestern energy. This continues until the pattern retracts far enough to alter the flow so that there is no more ascent over the Rockies being forced on an easterly or northeasterly flow, rather a typical westerly flow, and things can proceed. To give credit, this might have been something that Bastardi mentioned a while back, but I can’t recall, so if he did, then due credit to him, but this is the most logical thing I can come up with. Now, why it only seems to be a theme more recently? I don’t know lol

Although, I feel like I remember reading either ‘93-‘94 and/or ‘95-‘96 had a persistent southwestern trough like that which just kept sending impulses out along what was an essentially stalled frontal boundary throughout most of the winter. I’d have to check, though. Or, maybe one of our more seasoned veterans can add further insight into those winters, because I was too young for the meteorological component of memory at that point haha

[billg315]

I don't remember anything about the patterns that caused those winters, but I remember both of those winters well. 1994 was cold with numerous storms producing lots of snow N&W and a couple prodigious snow and ice storms along the I-95. 1996 was also cold and snowy with a historic snowstorm in early January. So, whatever we had those winters, bring it back. lol

[docstox12]

I don't remember anything about the patterns that caused those winters, but I remember both of those winters well. 1994 was cold with numerous storms producing lots of snow N&W and a couple prodigious snow and ice storms along the I-95. 1996 was also cold and snowy with a historic snowstorm in early January. So, whatever we had those winters, bring it back. lol

Right, both those winters, especially '95-'96, had one snowstorm after another hitting us.Don't know anything about the SW those years all I know in '93-'94 there was snow and ice in my backyard from late November through mid April.Pretty much the same in '95-'96.

[phil155]

I don't remember anything about the patterns that caused those winters, but I remember both of those winters well. 1994 was cold with numerous storms producing lots of snow N&W and a couple prodigious snow and ice storms along the I-95. 1996 was also cold and snowy with a historic snowstorm in early January. So, whatever we had those winters, bring it back. lol

I remember the blizzard of 96 very well, I was working for a delivery company in Hoboken while I was in college and the police shut everything down, it was snowing so hard I was not able to see much past the hood of my gmc jimmy. Incredible snow storm, a truly historic blizzard

[heehaw453]

We’re entering our first stretch of colder than normal weather for this season. And it will be here to stay for the next 7-9 days in part from an active MJO wave that is currently in phase 4 and heading into phase 5. This is shown to amplify the west coast ridge (+PNA) and keep the cold locked into the eastern US. Check out the Euro Ensembles 500mb Day 6-9 averages map.



The downsides I see are our trough axis and lack of NAO blocking. One trend I’m seeing in the medium to long range is that while the cold is here, the threat for storms is not as obvious because of the +NAO and progressive northern jet. The multiple waves of northern energy are not diving deep enough into the central/eastern CONUS despite the west coast ridging. One potential system catching my attention is shown between December 8th and 10th on current guidance. We could see some pseudo NAO blocking develop which is enough to slow the jet down and promote a more favorably positioned trough. So, let’s see if we’re able to get something come together because I do think come the middle of December we are likely going to get milder again (the MJO wave likely gets into the warm phases unless it dies off before it does).

Good post, Frank, although I'm going to respectfully disagree with the following:

"The downsides I see are our trough axis and lack of NAO blocking. One trend I’m seeing in the medium to long range is that while the cold is here, the threat for storms is not as obvious because of the +NAO and progressive northern jet. The multiple waves of northern energy are not diving deep enough into the central/eastern CONUS despite the west coast ridging."

I think verbatim you're right, but reading the tea leaves a bit I think reveals that your second thought regarding the potential for the pseudo NAO blocking is more accurate. What I think the models are currently having issues resolving is the response of southern tier of the western Atlantic domain. There's going to be a 50/50 low initially that looks to drift southeastward, which should result in height rises to its north. Simultaneously, we should see our storm of interest taking shape across the central U.S. as one piece of energy dives down the eastern flank of the ridge while another piece is ejecting out from the Southwest. As those phase, the long-wave trough is going to be forced to elongate and amplify, but in response to this AND the southeastward drift of the 50/50 low, height rises should* effectively pinch that southern lobe off from the main long-wave trough, resulting in a classic bowling ball closed mid-level low swinging through the interior Southeast with positive height anomalies arching over the top. Will it be classified as a technical -NAO? maybe, maybe not - statistics are a funny thing. But effectively, I think it should still function as one.

What is your observation as to why we're seeing so much pacific energy being held back in the SW CONUS? Is it just a function of the continuous retrograding and amplification of the PNA ridge to the north? Something about the pattern aloft does not feel quite right. Whether it's the split-flow look over the western U.S. or the positively tilted trough over the eastern U.S. I'm not so sure.
DEC 5th



DEC 8th



DEC 9th

Thinking more about your lead question, Frank, as I was drifting off to sleep while pondering my place and purpose in this universe, the true meaning of life, and a myriad of other questions that have baffled many a theologian (LOL), I came up with a hypothesis:

I wonder if the “drag” on the southwestern energy is manifested by upstream easterly or northeasterly flow coming across the Rockies behind the trough axis? In theory, that air is being driven to ascend, but because it’s ascending upstream of the trough axis, it acts “re-center” the base of the trough (thinking in terms of height anomalies). So instead of having a nice uniform trough that propagates smoothly over the Rockies and makes the bend, that trough base starts to distend and get distorted upstream. Given enough time, cold air keeps getting forced to rise over the Rockies upstream from the original trough axis on the easterly or northeasterly flow, which further cools it and continues to deepen the trough. The feedback continues, and as it does, that distorted trough re-centers further west with the new height field minimum, establishes a new trough axis, which then reorients the downstream height field enough to start redirecting some height falls BACK toward the Rockies. Continue this process, and consider that it’s occurring on the eastern flank of an anti-cyclonically breaking ridge (ridge folds over clockwise), which adds further easterly momentum flux beneath it, and that’s how you effectively trap the southwestern energy. This continues until the pattern retracts far enough to alter the flow so that there is no more ascent over the Rockies being forced on an easterly or northeasterly flow, rather a typical westerly flow, and things can proceed. To give credit, this might have been something that Bastardi mentioned a while back, but I can’t recall, so if he did, then due credit to him, but this is the most logical thing I can come up with. Now, why it only seems to be a theme more recently? I don’t know lol

Although, I feel like I remember reading either ‘93-‘94 and/or ‘95-‘96 had a persistent southwestern trough like that which just kept sending impulses out along what was an essentially stalled frontal boundary throughout most of the winter. I’d have to check, though. Or, maybe one of our more seasoned veterans can add further insight into those winters, because I was too young for the meteorological component of memory at that point haha

I think what made 95/96 special was the perpetual Atlantic trough. Time and time again it made colder scenarios win out helped by east based north Atlantic blocking via the Scandy ridge. That year wasn't helped too much by the PNA expect for the big dogs that year like Jan 6-8 blizzard which featured a modest PNA but look at the Atlantic trough buckling the entire Atlantic flow. That kept it cold and allowed the storm to meander. Whenever you see trough like that in Atlantic some areas on the east coast will be buried in snow. Happened a few years ago in March parts of MA got 40".

[heehaw453]

I know the 8th was a long shot but setup at D4 leads me to throw the towel in. What comes after it from 10th on it's too early to say but this particular setup won't due one bit as this is a setup for retreating cold air mass... Ugly

[sroc4]

I don't remember anything about the patterns that caused those winters, but I remember both of those winters well. 1994 was cold with numerous storms producing lots of snow N&W and a couple prodigious snow and ice storms along the I-95. 1996 was also cold and snowy with a historic snowstorm in early January. So, whatever we had those winters, bring it back. lol

I remember the blizzard of 96 very well, I was working for a delivery company in Hoboken while I was in college and the police shut everything down, it was snowing so hard I was not able to see much past the hood of my gmc jimmy. Incredible snow storm, a truly historic blizzard  

I too was in my college years up at Quinnipiac in CT.  At the time I was living on Whitney Ave in the "White House" and during the blizzard of 96, Whitney Ave was a deserted road so me and my friends hooked up a rope and a sled to the back of my jeep Cherokee and took turns in the sled or just hanging on with our hands to the bumper "skitching" on our feet ripping up and down Whitney almost killing ourselves.  Those were the days!

[dkodgis]

Last year=not really cold enough but enough moisture
This year=cold aplenty but not enough moisture.

Models go blind 9-8 days out and an ebb and flow of factors make forecasting anyone’s game. There. I think that’s it.

[billg315]

For now, I will take the cold even without the snow. I will definitely take the cold air and the generation of some snow cover across Canada, the Great Lakes and interior New England at this time as I think it bodes better for later in the season (certainly better than a December torch).
The reason I'm content to take cold without snow at this stage is, and I think Heehaw referenced this before, December really has never been prime "snowstorm" time for the Phila-NYC corridor. We CAN get December snowstorms for sure, but they are nowhere near as common in December as they are in January, February, and frankly I'd even argue March. A "white" Christmas in the Phila-NYC I-95 corridor, is not common.
So while a cold (or even "normal") December without much snow may not guarantee a snowy rest of winter, I think it holds more promise for the rest of the season than a pattern that brings us nothing but above normal temps in December.

[rb924119]

I know the 8th was a long shot but setup at D4 leads me to throw the towel in. What comes after it from 10th on it's too early to say but this particular setup won't due one bit as this is a setup for retreating cold air mass... Ugly

No disagreement from me here, man, though this wasn't a target period of mine anyway haha however, there have definitely been changes in the guidance for my 9th-12th threat window with respect to how guidance is looking to handle the whole evolution. The first round cuts - no doubt about it, not even wasting my time any longer trying to resurrect it. BUT, it's the progression that follows that first one that has me intrigued for the second scenario that I mentioned yesterday; delivery of truly Arctic-sourced air followed immediately by a wave amplifying along the frontal boundary. I don't have the time, energy, or mental fortitude at this point in my day to do a full video discussion or a full writeup, but I think I might try to do one tomorrow after work. The CliffNotes version, though, is the following based on today's 12z EPS, which I think looks the best overall right now, but I will briefly discuss where I think we will see additional corrections across guidance:



In the above image, I have three areas circled, with each circle representing one of the three key short-waves that we need/want to pay attention to. Also notice the disconnect in the negative height anomaly fields from the DN near Hudson Bay to the DN across the central CONUS. Now, take a look at the next frame, which is one day later:



In the above image, there's a lot going on, but what I am trying to demonstrate is:

1. yellow short-wave moves swiftly to the east in response to the massive PNA/EPO/AO ridge triplet, as it is sourced in the northern (really Pacific/"middle") stream, but the red short-wave still lags for reasons previously discussed earlier this morning. This essentially allows the yellow short-wave to compress the height field downstream as it propagates eastward (think confluence).

2. as the yellow short-wave moves quickly to the east, the green short-wave is rocketing down right on its heels in response to the PNA/EPO/AO ridge triplet - this is the fresh cold air delivery mechanism. Based on how I think it will eventually respond to the ridge triplet, I believe that this should start to be modeled to dive in sooner/stronger than it is currently. IF that's the case, then that would allow it to gain longitude faster than the red short-wave, which would mean that cold air gets established ahead of the approach of the red short-wave. Additionally, this would enhance the compression of the flow across the eastern CONUS, and push the same frontal boundary from the leading cutter further to the southeast. This then allows time for the red short-wave to round the bend. Once it does that, it will start to interact with the southern periphery of that frontal boundary and enhance the precipitation shield and organize a low-level circulation. How organized that low-level circulation can get and how quickly will be entirely dependent upon how strong that red short-wave is. The stronger it is, the quicker the circulation can organize, and a more robust, classic-looking storm we get. The weaker it is, the more of a broad quasi-linear precipitation shield we would see. The former would be more productive for snow purposes, as more lift would occur within the cold sector of the storm, but the latter would still work as this front will again be a steep one, which means that the lower-levels of the vertical thermal profile that matter most would essentially all be more or less aligned rather than gradually tilted with height, and I think current guidance is struggling to pick up on this just like it did a couple of weeks ago. Therefore, this would be a rain OR snow event, very little in-between.

Based on the above, my extremely preliminary thinking is that this may end up as an I-95 special, with a broad swath of 5-10/6-12" totals. We'll see. Good night, all!

WE TRACK!!!

[dkodgis]

[heehaw453]

Thanks Rb for that analysis always appreciated. I don't think this setup bodes well for 12/12 ATTM for an I95 special.  The reds in the 50/50 raise heights too much and will promote a lot warming. The PNA is positive but not anonymously so to dig this ULL. If we had a trough in the Atlantic and the reds above that I'd be interested in this but that's not how it looks to me. IMO anyway and your scenario is definitely possible but just think it takes a lot for the I95 to get snow out of this based on the h5.

[rb924119]

I don’t necessarily disagree with anything you mention heehaw. My opinion is that given the PNA/EPO/AO triplet, that’s a strong mechanism to drive cold air into the eastern CONUS. Added to the fact that the southern stream is lagging as a tail to the main trough, I think the models are under-representative of the speed with which the true northern stream can get out ahead of the southern stream and essentially erode the western flank of that Atlantic ridging before the southern stream starts gaining latitude, therefore over-representing the western periphery of the western Atlantic positive anomalies. So, those are the adjustments I’m looking for in current modeling, because verbatim, you’re 100% right.

[rb924119]

And, as a side note, I wouldn’t be surprised to see PNA heights trend stronger with time either given the jet dynamics associated with that Arctic wave.

[amugs]

Interestingly it does not get to Phase 6 by the EURO

GFS Has it hitting phase 6 by the 16/17th - that would stimk for Xmas

[amugs]

Thanks Rb for that analysis always appreciated. I don't think this setup bodes well for 12/12 ATTM for an I95 special.  The reds in the 50/50 raise heights too much and will promote a lot warming. The PNA is positive but not anonymously so to dig this ULL. If we had a trough in the Atlantic and the reds above that I'd be interested in this but that's not how it looks to me. IMO anyway and your scenario is definitely possible but just think it takes a lot for the I95 to get snow out of this based on the h5.

That is an absurd Full Lattitude Ridge!! IF we had a 50/50 then its game one but something else has to buckle the flow to get this for the coast IMO. Still 8 days away so an entiernity with a transitional month as we head into winter.
We shall dissect the next 24 runs of mdoels so let the chase begin!!

[sroc4]

I don’t necessarily disagree with anything you mention heehaw. My opinion is that given the PNA/EPO/AO triplet, that’s a strong mechanism to drive cold air into the eastern CONUS. Added to the fact that the southern stream is lagging as a tail to the main trough, I think the models are under-representative of the speed with which the true northern stream can get out ahead of the southern stream and essentially erode the western flank of that Atlantic ridging before the southern stream starts gaining latitude, therefore over-representing the western periphery of the western Atlantic positive anomalies. So, those are the adjustments I’m looking for in current modeling, because verbatim, you’re 100% right.

Without a true 50/50 low you will need a clipper like s/w to be ahead of, but not too far ahead, of any energy ejecting out of the SW to act as some sort of confluence to prevent the inevitable height rises out ahead of said SW energy and trap the cold to force the storm Track S&E of LI. We are going to need this little guy in the middle in order to have all these pieces to come together just right. IMHO not dead, but odds are not in our favor.

[rb924119]

Interestingly it does not get to Phase 6 by the EURO

GFS Has it hitting phase 6 by the 16/17th - that would stimk for Xmas

Some interesting things are unfolding in the longer range, mugsy, and I think any warmth or moderation we see could very well be a reset/reload period, an intermission, so to speak.

[frank 638]

Interestingly it does not get to Phase 6 by the EURO

GFS Has it hitting phase 6 by the 16/17th - that would stimk for Xmas

Some interesting things are unfolding in the longer range, mugsy, and I think any warmth or moderation we see could very well be a reset/reload period, an intermission, so to speak.

question do you think we will go back to a colder? Pattern by mid to late month.

[rb924119]

I don’t necessarily disagree with anything you mention heehaw. My opinion is that given the PNA/EPO/AO triplet, that’s a strong mechanism to drive cold air into the eastern CONUS. Added to the fact that the southern stream is lagging as a tail to the main trough, I think the models are under-representative of the speed with which the true northern stream can get out ahead of the southern stream and essentially erode the western flank of that Atlantic ridging before the southern stream starts gaining latitude, therefore over-representing the western periphery of the western Atlantic positive anomalies. So, those are the adjustments I’m looking for in current modeling, because verbatim, you’re 100% right.

Without a true 50/50 low you will need a clipper like s/w to be ahead of, but not too far ahead, of any energy ejecting out of the SW to act as some sort of confluence to prevent the inevitable height rises out ahead of said SW energy and trap the cold to force the storm Track S&E of LI.   We are going to need this little guy in the middle in order to have all these pieces to come together just right.  IMHO not dead, but odds are not in our favor.  

GFS made steps today at 12z. Not a trend, but I’d rather a change in the direction it went than another lol I don’t know what the GEM is doing, honestly, and I don’t think it knows what it’s doing either aha

[rb924119]

Interestingly it does not get to Phase 6 by the EURO

GFS Has it hitting phase 6 by the 16/17th - that would stimk for Xmas

Some interesting things are unfolding in the longer range, mugsy, and I think any warmth or moderation we see could very well be a reset/reload period, an intermission, so to speak.

question do you think we will go back to a colder? Pattern by mid to late month.

I can’t really answer this yet, as I’ve been primarily focused on the 9th-12th right now, but, I think we can manage a return to a time-mean trough in the eastern CONUS from the 20th onward. I’ll have more to say on this later, though.

[heehaw453]

I don’t necessarily disagree with anything you mention heehaw. My opinion is that given the PNA/EPO/AO triplet, that’s a strong mechanism to drive cold air into the eastern CONUS. Added to the fact that the southern stream is lagging as a tail to the main trough, I think the models are under-representative of the speed with which the true northern stream can get out ahead of the southern stream and essentially erode the western flank of that Atlantic ridging before the southern stream starts gaining latitude, therefore over-representing the western periphery of the western Atlantic positive anomalies. So, those are the adjustments I’m looking for in current modeling, because verbatim, you’re 100% right.

Without a true 50/50 low you will need a clipper like s/w to be ahead of, but not too far ahead, of any energy ejecting out of the SW to act as some sort of confluence to prevent the inevitable height rises out ahead of said SW energy and trap the cold to force the storm Track S&E of LI.   We are going to need this little guy in the middle in order to have all these pieces to come together just right.  IMHO not dead, but odds are not in our favor.  

GFS made steps today at 12z. Not a trend, but I’d rather a change in the direction it went than another lol I don’t know what the GEM is doing, honestly, and I don’t think it knows what it’s doing either aha

Agreed. GEFS basically I81 and westward is the spot where cold air meets the moisture. 7 days and model variability can still be quite high. Lack of Atlantic trough in early/mid December for snow on the 95 makes me very cautious w/out a big dome of H pressure parked over Quebec/NNE. But on the other hand the NAO/AO are - whilst the PNA is + which are normally very correlated to sig snow in the I95. Also, inflection points of the teleconnections tends to be associated with bigger storms. We'll see next few days...

all of the above...

[rb924119]

I don’t necessarily disagree with anything you mention heehaw. My opinion is that given the PNA/EPO/AO triplet, that’s a strong mechanism to drive cold air into the eastern CONUS. Added to the fact that the southern stream is lagging as a tail to the main trough, I think the models are under-representative of the speed with which the true northern stream can get out ahead of the southern stream and essentially erode the western flank of that Atlantic ridging before the southern stream starts gaining latitude, therefore over-representing the western periphery of the western Atlantic positive anomalies. So, those are the adjustments I’m looking for in current modeling, because verbatim, you’re 100% right.

Without a true 50/50 low you will need a clipper like s/w to be ahead of, but not too far ahead, of any energy ejecting out of the SW to act as some sort of confluence to prevent the inevitable height rises out ahead of said SW energy and trap the cold to force the storm Track S&E of LI.   We are going to need this little guy in the middle in order to have all these pieces to come together just right.  IMHO not dead, but odds are not in our favor.  

GFS made steps today at 12z. Not a trend, but I’d rather a change in the direction it went than another lol I don’t know what the GEM is doing, honestly, and I don’t think it knows what it’s doing either aha

Agreed. GEFS basically I81 and westward is the spot where cold air meets the moisture. 7 days and model variability can still be quite high. Lack of Atlantic trough in early/mid December for snow on the 95 makes me very cautious w/out a big dome of H pressure parked over Quebec/NNE. But on the other hand the NAO/AO are - whilst the PNA is + which are normally very correlated to sig snow in the I95. Also, inflection points of the teleconnections tends to be associated with bigger storms. We'll see next few days...

all of the above...

Food for thought, heehaw, regarding your “lack of a dome of high pressure parked over Quebec/northern New England”…..

Today’s 12z GFS:



These are changes I expect to continue. But that’s feeding fresh Arctic air into this thing from the north and northwest, and it’s pressing HARD.

[rb924119]

That would have very strong isallobaric flow, and would turn out colder than currently modeled. Guaranteed. Now, we shift that another 100 miles further southeast, and you’re in the money. Over the span of eight days, I’ll take my chances and trust the process.

[rb924119]

Btw, 12z EURO just followed the GFS. Snow for the I-95 Corridor. Game on.



Cursory glance at dynamics, precip would be much more plentiful and would result in at least double the totals shown here.

[heehaw453]

I don’t necessarily disagree with anything you mention heehaw. My opinion is that given the PNA/EPO/AO triplet, that’s a strong mechanism to drive cold air into the eastern CONUS. Added to the fact that the southern stream is lagging as a tail to the main trough, I think the models are under-representative of the speed with which the true northern stream can get out ahead of the southern stream and essentially erode the western flank of that Atlantic ridging before the southern stream starts gaining latitude, therefore over-representing the western periphery of the western Atlantic positive anomalies. So, those are the adjustments I’m looking for in current modeling, because verbatim, you’re 100% right.

Without a true 50/50 low you will need a clipper like s/w to be ahead of, but not too far ahead, of any energy ejecting out of the SW to act as some sort of confluence to prevent the inevitable height rises out ahead of said SW energy and trap the cold to force the storm Track S&E of LI.   We are going to need this little guy in the middle in order to have all these pieces to come together just right.  IMHO not dead, but odds are not in our favor.  

GFS made steps today at 12z. Not a trend, but I’d rather a change in the direction it went than another lol I don’t know what the GEM is doing, honestly, and I don’t think it knows what it’s doing either aha

Agreed. GEFS basically I81 and westward is the spot where cold air meets the moisture. 7 days and model variability can still be quite high. Lack of Atlantic trough in early/mid December for snow on the 95 makes me very cautious w/out a big dome of H pressure parked over Quebec/NNE. But on the other hand the NAO/AO are - whilst the PNA is + which are normally very correlated to sig snow in the I95. Also, inflection points of the teleconnections tends to be associated with bigger storms. We'll see next few days...

all of the above...

Food for thought, heehaw, regarding your “lack of a dome of high pressure parked over Quebec/northern New England”…..

Today’s 12z GFS:



These are changes I expect to continue. But that’s feeding fresh Arctic air into this thing from the north and northwest, and it’s pressing HARD.

I agree with that. What i meant is something already established though. It's a race here and believe further westward is much better position to benefit. If we had the Atl trough this would be much much easier as we'd minimize the warm air and it'd slow this bad boy down some.

This is def cold air on the move.

[rb924119]

I don’t necessarily disagree with anything you mention heehaw. My opinion is that given the PNA/EPO/AO triplet, that’s a strong mechanism to drive cold air into the eastern CONUS. Added to the fact that the southern stream is lagging as a tail to the main trough, I think the models are under-representative of the speed with which the true northern stream can get out ahead of the southern stream and essentially erode the western flank of that Atlantic ridging before the southern stream starts gaining latitude, therefore over-representing the western periphery of the western Atlantic positive anomalies. So, those are the adjustments I’m looking for in current modeling, because verbatim, you’re 100% right.

Without a true 50/50 low you will need a clipper like s/w to be ahead of, but not too far ahead, of any energy ejecting out of the SW to act as some sort of confluence to prevent the inevitable height rises out ahead of said SW energy and trap the cold to force the storm Track S&E of LI.   We are going to need this little guy in the middle in order to have all these pieces to come together just right.  IMHO not dead, but odds are not in our favor.  

GFS made steps today at 12z. Not a trend, but I’d rather a change in the direction it went than another lol I don’t know what the GEM is doing, honestly, and I don’t think it knows what it’s doing either aha

Agreed. GEFS basically I81 and westward is the spot where cold air meets the moisture. 7 days and model variability can still be quite high. Lack of Atlantic trough in early/mid December for snow on the 95 makes me very cautious w/out a big dome of H pressure parked over Quebec/NNE. But on the other hand the NAO/AO are - whilst the PNA is + which are normally very correlated to sig snow in the I95. Also, inflection points of the teleconnections tends to be associated with bigger storms. We'll see next few days...

all of the above...

Food for thought, heehaw, regarding your “lack of a dome of high pressure parked over Quebec/northern New England”…..

Today’s 12z GFS:



These are changes I expect to continue. But that’s feeding fresh Arctic air into this thing from the north and northwest, and it’s pressing HARD.