Winter storm threat ...early ideas

[Typhoon Tip]

For the general enthusiasts et al:

There are problems with the system roughly D5-8 as of the 00z Jan 1 runs across the board. The upshot is that we have plenty enough lead time to morph things more favorably ( So please no grousing - ), but this is what we should be look for in future runs:

1) Less leading gradient in the geopotential medium over the TV, along with needing to have erosion of the heights over the northern Gulf and throughout FL and adjacent areas. As is modeled ... there is a slight positive anomaly there that is accentuated tremendously by anomalous blocking up in Canada associated with evolving westerly oriented -NAO. That blocking is intermediately pinning a strong negative anomaly through southern and southeastern Canada. Typically in that configuration too much gradient evolves farther south in the balanced medium of the atmosphere; the result of which means that systems attempting to move through 35-45N belt by 100-70W approximate rectangulum are shearing - this is more technically a negative wave interference (which for you youngins you'll learn what that means in physical terms in the coming torturous academic journey of the doggedly determined to never find a job Meteorological hopeful...) that is effective at both the L/W and S/W length scales.

The balanced flow through that region would have been anomalously fast anyway given to such a strong blocking pinning that negative region N as described, but here it is augmented even higher by the fact that for 48 to 72 hour prior to the trough in the deep SW CONUS region was pumping heights up down stream in the lower MV, TV and Gulf regions. The end result is that the balanced flow has over 70kts of geostrophic wind in some areas, and that is too much.

2) More southern stream dynamics needs to come through the western ridge - or perhaps doing so as an over-the-topper intermediate stream S/W like in 1978. What that would do is assist the erosion of the medium as described above. The following is a case study that examplifies this process:

The 00z ECM is pretty close actually at doing this with an over-the-topper. At 144 hours it has a nice area of positive vorticity coming off the Pacific, and this zooms over the top of the ridge, dives ESE through the western lakes and triggers the subsuming of the SPV south.

I am not sure folks realize just how close that is to the makings of an event that would rival the last. It's probably a matter of 6DM or so height resistance away from both digging the core of the negative anomaly more convincing under the 40N latitude, which would simultaneously dramatically improve the DPVA as it does so. That is all code for KerBAM BOOMBA BOMB (check page 172 of AMS Glossary of terms - LOL). At 6 days away, do we want to hedge our bets that a stronger Pac injection won't take place? No, if we have an iota of intellect we would not. The 06z GFS is actually somewhat similar, but is actually even weaker with the southern and/or intermediate dynamics. There is some present in that run, but by and large the run uses almost entirely the SPV to do everything. That almost reminds me of a March 2001 scenario there, but perhaps displaced farther up the coast. At this range however it is axiomatic not to take anything verbatim of course...

12z guidance is on the way as I type. It will be interesting to see if there is any converging beginning toward more amplitude, and finding means to lower the gradient in the deep south and southeast enough for this to come together. As an early probability, the greatest is up in New England, but like the last event, I do not believe the MA should be discounted, particularly the northern half of the MA. (I believe I mentioned that during the last radio show leading...)

Concluding comments: I seem to recall there were a couple of cycles prior to the last historic-for-the-MA-while-wasting-the-time-for-interior-SNE, storm that a wave some 3 days prior to the main show was also monitored (there is some interest in a clipper-type system up in the NE thread). In a way, we are in a similar scenario with this will-it-or-won't-it clipper; maybe we can will it into being? Anyway, enough so that my thoughts as I came out of slumber this morning went to repeating historic bomb winter of 2010-2011, perhaps a rare phenomenon.

This issue for me is that frankly I do not believe we are going to ever see a meaningful -AO/-NAO recovery this year. The AMO and the solar cycle are strong linear correlations and both are aiming downward quite discerned. Moreover, the -AO overall in the hemisphere is masking the typical La Nina regime; in fact, because the gradients are what they are, we are almost seeing a more Le Nino like deal with all these coastals. But that is supposition... perhaps a good discussion topic. The point is, the governing parameters do not appear to really have a means to change before this cold season's overall characteristic is in the books. The -AO and La Nina during a negative solar cycle just may appear to be a gem of the year? Could be... If nothing else I believe it underscores the necessity in season outlook efforts to include the polar field indices. Those that were heavily ENSO reliant are probably running into some problems with their outlooks I would imagine. That is not to criticize - it would be unfair to do so considering I did not put out an outlook. But just some friendly advice.

John

[ME_wannabe]

John,

I always enjoy your thoughtful posts. Looking forward to your continued analysis within this thread. Thanks

[Atlas]

Tip, 12z GFS really going gung-ho on the Miller B idea. GREAT post!

[PhineasC]

The 12Z GFS depiction is the sort that screws south of PHL. Don't waste your time tracking this if you live there.

[Typhoon Tip]

The 12Z GFS depiction is the sort that screws south of PHL. Don't waste your time tracking this if you live there.

Too early for that...but admittedly, as is I would like to see more erosion in the ridging to your south. There is time for that to take place, however. We are still talking days and days away and calmly monitoring.

Btw for all: the NAO at CPC is showing a +2SD recovery - reflected in the deterministic GFS as the ridge retrogrades W away from the Greenland hot spot. This does offer a teleconnector support for a migrating negative geopotential region in the OV and MA regions. I know that others have voiced opposition in using the CPC values, but I have come to find they apply brilliantly depending on the situation. CDC as well..., in this case they do not show the same discerned rise.

I believe the domains must be different in the spatial computation - that would explain that. CDC lists their rectangle - have to dig to find CPCs domain though.

Anyway, both CPC and CDC offer a "spike" of sorts in the PNA centered on week's end, so there is teleconnector convergence fwiw -

[Edge Weather]

12z Canadian.

[Edge Weather]

12z GFS deepens this thing to 960 mb at 168 hrs.

[Edge Weather]

12z UKMET

[Typhoon Tip]

I'm honestly amazed at the 12z GFS - it really does seem to be trying to achieve much of this.... 12z Euro is coming out shortly.

Hearkens to a discussion I had with Dr. Colby up at UML where when there are more important systems in the physics, they tend to shimmer out of the model depictions earlier than is typical. The last juggernaut KU system notwithstanding ...the GFS, though flaky on final approach, was doggedly determined to whack the MA and NE for almost 3 straight days worth of runs some 7 or 8 days before hand. 1997, 1993, 1978 even ...going back in time, these bigger events do tend to show up early. Hmmm

[Typhoon Tip]

The 12z deterministic ECMWF run shows at 96 hours that the 582DM height contour is now S of the southern peninsula of FL. That implies reducing resistance. There is also a little more intermediate/southern stream dynamics to offer a better phase out in time. Regardless, this run seems to just miss doing so by a razor thin margin for error... We see a weak coastal reflection and an exotically stretched Miller B presentation in the isobaric layout by 120 hours; the natural question still unanswered points to whether that phase doesn't take place 6 or so hours faster - should that come to pass, look out!

[eduggs]

I see almost no southern or "intermediate" stream involvement in the 12z GFS solution. Frankly, I don't think it's needed when the entire pv structure (sub 500dm and all) rotates down into the mid-atlantic. But I expect something much closer to the 12z ECM.

The point I'm trying to make is that I don't believe a dampening southern stream s/w traversing the deep south modifies the height field sufficiently to provide much assistance. I believe the s/w has to get to a neutral or downstream position with respect to the trof axis to promote a favorable location for coastal cyclogenesis - the 12z GGEM for example - which ironically mostly misses. But more importantly I think a purely northern stream (if you want to call it that) is sufficient provided the pv takes a favorable (slightly southerly) path.

[Amped]

Jan 1966 Had a southern stream and thinggs worked out, not great for the immediate coast though.

[Typhoon Tip]

I see almost no southern or "intermediate" stream involvement in the 12z GFS solution. Frankly, I don't think it's needed when the entire pv structure (sub 500dm and all) rotates down into the mid-atlantic. But I expect something much closer to the 12z ECM.

The point I'm trying to make is that I don't believe a dampening southern stream s/w traversing the deep south modifies the height field sufficiently to provide much assistance. I believe the s/w has to get to a neutral or downstream position with respect to the trof axis to promote a favorable location for coastal cyclogenesis - the 12z GGEM for example - which ironically mostly misses. But more importantly I think a purely northern stream (if you want to call it that) is sufficient provided the pv takes a favorable (slightly southerly) path.

Understood, but it is there...

[eduggs]

Understood, but it is there...

Cool.

[Typhoon Tip]

Jan 1966 Had a southern stream and thinggs worked out, not great for the immediate coast though.

Do you have a specific date on that; I like to look those up at NCEP's library when people reference events like that -

[Amped]

Do you have a specific date on that; I like to look those up at NCEP's library when people reference events like that -

January 30th

[Typhoon Tip]

Jan 1966 Had a southern stream and thinggs worked out, not great for the immediate coast though.

That was a good example actually, where the southern stream helped induce the SPV southward to where it then took over. Fact of the matter is, that model of phasing is a basic paradigm that should be looked in most cases.

The 00z Euro run looks excessively odd over western N/A going from hours 120 into 144. It is difficult to see where it gets the physics to morph the top of the ridge with all that spontaneously emerged +vorticity. This then distorts the flow down wind - probably away from what will ultimately transpire (whatever that will be).

One thing I found intriguing is that the one model that typically carries a huge amplitude suppression bias beyond 72 hours was the one model on both the 00z and 06z that is the most cohesively deep and amplified: the NOGAPS - or as I like to refer to as the "GONAPS"

00z GFS was failing to phase entirely; it instead takes the discussed southern stream S/W (that apparently some are having difficulty identifying in the flow) and spinning up lead cyclogenesis that zips seaward. Normally, that would put the kibosh on anything additional because it would mean taking the baroclinic axis and evacuating it too far off the eastern seaboard. But in this case, the model is so deep and anomalous with the SPV - which the southern stream did actually aid it bringing down ironically - it finds the wherewithal to develop a new low that pummels SNE. I suppose that idea overall is possible... though not pretty. It would bring a band of light to moderate snow from the eastern TV regions up into the lower middle Atlantic, with perhaps just snow in the air up further north, then the latter explosive development affecting primarily SNE. I have seen this type of modeled solution at this kind of late middle range time lead in the past, and typically what plays out is all or nothing in reality.

The 00z GGEM showed a really goot subsume scenario but then doesn't bring the SPV far enough south to really interact with the baroclincic gradients in time for the pretty much everyone - that idiosyncrasy causes a larger amorphous region of low pressure with shredded bands of light to moderate snow impossible to locate.

All in all, the 00z suite (and what I have seen of the 06z) was not stellar on a lot of this 'what needs to happen'. The system is still there and should not be discounted... In any event, we should soon encounter an interval of model blackout where for some reason they unilaterally drop the system altogether, ...only to bring it back with a fervent vengeance some day or day and half later. Don't be surprised if that happens either. I like the fact that the teleconnector modalities still support a system, however.

[Amped]

ECMWF has an NYC North storm at 120h-144hrs. Even better setup day 7. Also it keeps the SPV in Canada, it never sweeps off the east coast like the GFS

[Atlas]

Looks like the 00z EURO went "Kaboom"

[Typhoon Tip]

I realize there is a 00z ECMWF thread going so I won't go too much into detail, but sufficed it is to say (and likely covered over there) I'd be conservative on that run until there is a better agreement from the other guidance sources - although the 06z did "trend" that way some.

I will say, however, that the subsuming scenario heavily covered in the OP of this thread is being tapped into by this ECM run. This could very well end up being a big score from DCA up the the Coast for having nailed the timing of the erosive southern stream upon the flat SE ridge, then allowing lowered resistance to plunging SPV.

That latter system has been covered by others...DT, HM ...et al.

[Typhoon Tip]

Fascinating assertion from HPC this morning regarding this potential:

VALID 12Z FRI JAN 07 2011 - 12Z MON JAN 10 2011 THE MAIN ALTERATION TO THE UPDATED PRELIM PROGS WAS TO

ADJUST SWWDA POSSIBLE MAJOR STORM ALONG THE NRN MID ATLANTIC COAST IN THE DAY4-6 FRI-SUN TIME FRAME.

WHILE THE DETERMINISTIC ECMWF IS A RATHEREXTREME SWRN OUTLIER IN DROPPING A PIECE OF POLAR VORTEX SSE ALLTHE WAY FROM HUDSON BAY TO VA...

THE 06Z/03 GFS HAS TRENDED A BITTOWARDS THE ECMWF SOLUTION SAT...GIVING A NEWD ADJUSTED ECMWFSCENARIO SOME CREDIBILITY.

THIS MAINTAINS REASONABLE HPCCONTINUITY WITH THIS POTENTIAL E COAST SYS OVER THE PAST TWO DAYS.WHILE NOT OVERPLAYING ANALOGS...

I STILL WANT TO POINT OUT SOMESIMILARITY IN THE PRESENT HPC SCENARIO THIS WEEKEND TO THAT OF FEB6 1978...ESPECIALLY AT 500 MILLIBARS...

WHICH WAS A MAJOR BLIZZARDFOR ERN PA/NY/NEW ENG. THE 00Z ECENS AND 06Z GEFS MODEL MEANS SUGGEST THAT AN ANOTHERAREA TO WATCH CONCERNS THE NEW TROF DIGGING INTO THE WERNSTATES... WHERE ECMWF ENSEMBLE MEBERS SUGGEST A DEEPER TROF EARLYNEXT WEEK.

He/she is right not to overplay analogs - I too sometimes find that too reliant - but it is intriguing that the Feb6 1978 scenario was outlined in this thread's OP, and here we are two days later and it is popping out as a primary example - INDEED.

After reviewing more data I beileve there is pretty good potential that the 12z GFS arrives more in line. The 06z is a red flag here - it's like another GFS ensemble member, and since 2 or 3 of the 00z members were a reasonable comparison to the deterministic ECM, I have seen this modeling behavior in the past and it tends to lead the next cycle where convergence begins. ...Not every time of course, but if you are a storm enthusiast and need to see it in the runs to "feel good" about things, I think you are heading for a massaging here.

Cons: I don't like the fact that the 00z ECM is just as discontinous a solution as the previous 3 cycles, which were prety rigorously re-adjusting everything en masse across each run. That said, it offers a bit of consternation that this run is the best fit for teleconnector modalities. Hemmm... ouch.

[Typhoon Tip]

Yea, I dunno - seeing the 00z "GONAPS" model over come its striking longitudinal, no amplitude bias and drilling a -3 or 4 SD negative anomally under LI at 120-132 hours is pretty alarming.

It raises my confidence that the 12z runs are likely to start converging toward the wheelhouse range of the deterministic Euro despite continuity problems.

[showmethesnow]

Fascinating assertion from HPC this morning regarding this potential:

VALID 12Z FRI JAN 07 2011 - 12Z MON JAN 10 2011 THE MAIN ALTERATION TO THE UPDATED PRELIM PROGS WAS TO

ADJUST SWWDA POSSIBLE MAJOR STORM ALONG THE NRN MID ATLANTIC COAST IN THE DAY4-6 FRI-SUN TIME FRAME.

WHILE THE DETERMINISTIC ECMWF IS A RATHEREXTREME SWRN OUTLIER IN DROPPING A PIECE OF POLAR VORTEX SSE ALLTHE WAY FROM HUDSON BAY TO VA...

THE 06Z/03 GFS HAS TRENDED A BITTOWARDS THE ECMWF SOLUTION SAT...GIVING A NEWD ADJUSTED ECMWFSCENARIO SOME CREDIBILITY.

THIS MAINTAINS REASONABLE HPCCONTINUITY WITH THIS POTENTIAL E COAST SYS OVER THE PAST TWO DAYS.WHILE NOT OVERPLAYING ANALOGS...

I STILL WANT TO POINT OUT SOMESIMILARITY IN THE PRESENT HPC SCENARIO THIS WEEKEND TO THAT OF FEB6 1978...ESPECIALLY AT 500 MILLIBARS...

WHICH WAS A MAJOR BLIZZARDFOR ERN PA/NY/NEW ENG. THE 00Z ECENS AND 06Z GEFS MODEL MEANS SUGGEST THAT AN ANOTHERAREA TO WATCH CONCERNS THE NEW TROF DIGGING INTO THE WERNSTATES... WHERE ECMWF ENSEMBLE MEBERS SUGGEST A DEEPER TROF EARLYNEXT WEEK.

He/she is right not to overplay analogs - I too sometimes find that too reliant - but it is intriguing that the Feb6 1978 scenario was outlined in this thread's OP, and here we are two days later and it is popping out as a primary example - INDEED.

After reviewing more data I beileve there is pretty good potential that the 12z GFS arrives more in line. The 06z is a red flag here - it's like another GFS ensemble member, and since 2 or 3 of the 00z members were a reasonable comparison to the deterministic ECM, I have seen this modeling behavior in the past and it tends to lead the next cycle where convergence begins. ...Not every time of course, but if you are a storm enthusiast and need to see it in the runs to "feel good" about things, I think you are heading for a massaging here.

Cons: I don't like the fact that the 00z ECM is just as discontinous a solution as the previous 3 cycles, which were prety rigorously re-adjusting everything en masse across each run. That said, it offers a bit of consternation that this run is the best fit for teleconnector modalities. Hemmm... ouch.

You mentioned only 2 or 3 members from the 00Z GFS were a reasonable comparrison. I had posted earlier that I thought 5 were similiar in the setup of the PV. Just wondering what I am missing when it comes to comparisons and what I should probably should be looking for.

[jrodd321]

Yea, I dunno - seeing the 00z "GONAPS" model over come its striking longitudinal, no amplitude bias and drilling a -3 or 4 SD negative anomally under LI at 120-132 hours is pretty alarming.

It raises my confidence that the 12z runs are likely to start converging toward the wheelhouse range of the deterministic Euro despite continuity problems.

Post made my day.

[Typhoon Tip]

You mentioned only 2 or 3 members from the 00Z GFS were a reasonable comparrison. I had posted earlier that I thought 5 were similiar in the setup of the PV. Just wondering what I am missing when it comes to comparisons and what I should probably should be looking for.

I didn't study them that closely in all honesty so you may be right... I just glanced at the 500mb level height evolution spanning the period and noted what I thought off the bat were the best comparisons, but upon closer inspection "reasonable" may apply to others.

There's probably no point to being so precise at this range but noting ensemble comparability is always a good thing, either way.

[Hailstoned]

FWIW, the 78 blizzard occurred around the time of the new moon as would any Great Pretender late this week.

[Typhoon Tip]

12z GFS as expected trends toward the Euro, but they disagree on the extent of latitudinal placement at 96-120 hours

still time to iron that out... Probably the Euro comes a bit farther N while future GFS runs settle SW some... pin point the best statistical location for the compensating retrograde up N

[Sampson]

Great job pulling up 78 a few days ago. Whether or not it verifies is insignificant, the idea that you're really doing your homework lends credence to all of your posts.

[Wow]

12z Euro says don't even think about it.

[Typhoon Tip]

12z Euro says don't even think about it.

The ECM has been problematic lately.

There's that, and, if there were no teleconnector support and the other guidance were doing something else I'd have less problem with it; but seeing as precisely the opposite is true in both cases, I'm willing to think this is no different than that 1.5 days worth of runs it lost the last big event. Remember? I lost count of the "this threat is essentially dead" posts, yet full on blizts struck from VA-ME.