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Storm next weekend has better teleconnector support than this misery ever did

Typhoon Tip

By Typhoon Tip,
in New England

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Typhoon Tip

Typhoon Tip

Posted
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Hi all -

The flow beneath extensive high latitude -AO/-NAO attributed blocking is complex, with multi-nodal SPV connecting a general band of negative geopotential anomalies along 45-55 W in the means. At any given time a more intermediate and/or southern stream S/W will tend to cut underneath, threatening a phase and deeper cyclogenesis, but this is inherently a stochastic affair in the models as this recent event certainly pointed out.

Firstly regarding the nearer term: there is still some potential remaining that the [now] early to midweek system will affect some portion of southern and eastern New England. Here are the issues with this event:

The low-level baroclinic axis is suppressed unusually far east and south along and off the eastern seaboard. This combined with [likely] convective feedback processing in the models is causing surface depictions across multiple guidance types to be displaced east and or south of the better theoretical position beneath superior deep layer forcing. The main jet axis leaves the NJ Coast with its left and right entrance regions nosing out over waters south of Long Island

post-904-0-47348400-1292694759.jpg

as the above annotated images show. There could be an error that we have not collectively been discussing. Moreover, looking out to 72 hours and beyond, we see that the NAM model is attempting to perhaps correct for this [error] by anchoring a deep layer, deep vortex concatenated under the U/A closed low, while the original low it was developing amid the convective mass is attempting to escape and shear eastward - a condition that looks more +NAO than -NAO, so is not very well teleconnection supported.

Last night's runs unilaterally showed forsaking those governing dynamics for convection out over the outer Gulf Stream and west Atlantic Basin, keying in on any one of the resulting convective induced vorticity maxima and using it to mechanize a deep gale quite far displaced east from the better divergence aloft. I don't believe that is right. I would be more willing to go with convection streaking out and perhaps robbing cyclogenesis farther NW over actually having a main show low event deep southeast where the thermal gradient is weak and there is an absence of frontal slopes to force synoptic scale lift; jet interaction/cross-sectional analysis would not support.

That said, if there are some mechanical processes not readily observable in these prognostics they may turn up with some other analysis.

I see some chance that a stronger low may anchor in farther W, and that there would be some retrograde motion into eastern areas of New England with some snow. For now, will leave it at that.

On to next weekend:

This event has more teleconnector-related intuitive support for actually having a chance to happen than the nearer term. Both the CDC and CPC are showing a relaxation of the NAO, supplying a less suppressed/negative wave interference on the means.

post-904-0-12745000-1292697090.jpg

The PNA is what is more intriguing however, showing a lot of members clustered enough for a concerted rise from a long standing -negative phase state; hence enters the modal shift of the PNA. However long lasting aside, one that recovers almost 2 full SD, it would be hard to perceive that can occur without at last altering the characteristic of the flow amid the Pacific relay into North America. As certain scientist have shown statistically, particularly during modal periods of the PNA during cold season, large synoptic scale precipitation events are favored. The reasons for that on a more physical level are pretty obvious, in that when the modal intervals are taking place, this means large scale mixing of differentiable air masses taking place, hence instability at large scales leads to storm development.

post-904-0-12745000-1292697090.jpg

3.5 days from now the CPC intensely clustered members have a PNA that starts concertedly rising out through D10. This centers wonderfully on next weekend's shortening of the L/W lengths.

Lastly, the MJO was decaying out of Phase 5 and through 6 over the last week. Incidently this was not a statistical fit for EC storms. But, it is appearing to re-strengthen entering Phase 7, and that should time for late Phase 7 and early 8 by next weekend, which statistically IS a good fit. I don't have a lot of experience using the MJO for single planetary events - and I don't think it should. Nonetheless, the numbers still fall out that way and Phase 8 and 1 tend to own the lion's share of coincident EC events.

John

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weatherwiz

weatherwiz

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Great writeup!

If we indeed do see somewhat of a relaxing -NAO this would definitely play into our favor as it would allow for the pattern to somewhat relax and we wouldn't see everything so suppressed which means we should get the baroclinic zone to shift northward somewhat and with a relaxing of the -PNA that should also mean the baroclinic zone shifts west a bit as well.

Something I was wondering about which someone made mention to me last night was with this system for Sunday/Monday there looks to be an area of high pressure sitting right over the OV region...is it possible that this high pressure is acting to push the southern stream energy further off the coast and allowing the northern stream energy to weaken and not phase with the southern stream energy?

Looks like we don't see any high pressure over the OV next weekend per the GFS.

Just a thought...

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Typhoon Tip

Typhoon Tip

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thanx Scoot'

i was just reviewing the 18z NAM and am noting that we are indeed getting gradually more cohesive circulation developing NW of the prior runs beginning 06z through this one. This may be a beginning attempt to confirm the idea that the models have been a bit underdone, while over-emphasizing the significance of convective action farther SE.

still time believe it or not for this to pop surprise eastern NE.

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mahk_webstah

mahk_webstah

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Agreed....I said yesterday that I needed to see it on a EURO run and now I have.

That is a nice high in a really nice spot.

Thank you sir Euro please give it to me again.

My feeling about this winter is that once the dam is broken we are good. I envision (from my deep meteorological knowledge) that we get one or 2 good snows over the next 10 days and then as the pattenr relaxes we get into a situation where it is not so consistently cold, and our snow pack helps create a gradient that storms travel along. That gradient would be very near or in New England. CNE and NNE would probably do the best but SNE would have some fun as well. We would shift towards more SWFE events and occassionally blocking would help with a Miller B or two. We would get some torching episodes but at least for some of us our snowpack would mute that. At some point later in the winter we get another big pattern shift and at that time there is an opportunity for a big storm/Miller A kinda deal.

That's basically how I see this winter going. I think I end up with 70-90 inches.

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Typhoon Tip

Typhoon Tip

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Interesting to see the 00Z Euro continue the trend of emergent agreement with this GFS/teleconnector supported thinking regarding what may very well be dubbed the Christmas Bomb.

I have to say, of all the models I am most astonished by the UKMET 144-hour appearance that would certainly extrapolate into a magnificently powerful, powerful entity over either the MA, or off shore (not too much hopefully). Deep S and SE heights well prior to the arrival of western N/A quasi PNA (or outright so) ridge amplitude are hugely compressible with feather balanced mid level velocities over the Gulf and Florida noted, and the 576 DM contour displaced S of MIA! It's always nice to have a neutral/negative geopotential medium BEFORE the arrival of the actual negative anomaly associated with said synoptic amplification; that way you are at least settled in the notion that there is limited or no ability to shear dynamics as they arrive. So the contouring takes on the classic ski slope from Edmonton Alberta to Cincinnati Ohio, where we see bubble lead S/W ridging on the rise, which would migrate up into confluence and strengthening the polar PP arm N of NE. Boy I tell you that is a tasty, tasty design if you know what you are looking at; particularly because if you look at that closely you see a "dent" in the ski slope over Manitoba. That dent is a polar/arctic embedded S/W with [probably] an attendant 110kt 500mb jet core, and that bad boy is on an Olympic mission for gold! What would have to play out there is that it would rip SSE and carve out a whopper over OV-MA to eventually S of LI, and with that train wreck SPV over the upper-outer Maritimes ...

I think I'll just stop there, but sufficed it is to say, that pattern has the look of one that would reverse the seasonal snowfall anomaly distribution with extreme rapidity.

The Canadian GGEM is as usual being pissy because this pattern completely annihilates any means for it to exercise it's westerly absurd bias right beyond D4, so it ops to not have a system altogether - hey that works :arrowhead: Toss the 00Z GGEM.

The overnight teleconnector derivations at both the CDC and CPC are still flagging D5-10 period as the best playing field for whacking one out of the park and scoring in all this insanity.

Regarding the days prior to... Well, the 00z NAM's fantasy addition of driving the storm back NW as a trend continuance has ceased, and now that it has tugged at the hearts and souls of Wiener America one last time to satisfy it's cruel hideous amusement, it appears the best hope for getting any snow over the next 60 hours will have to be from retrograde motion as originally discussed. One thing I'd add there; one thing that all these NAM runs have in common is that obvious Norlun like signature setting up across central New England and then settling south around mid week. Probably should not discount that altogether because the deep layer flow does support some type of lingering convergence axis of that nature.

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Typhoon Tip

Typhoon Tip

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Sometimes it just makes too much sense...

THE FORECAST SPREAD/SOLUTION ENVELOPE REMAINS SMALLER THAN NORMAL

AS MODELS AND ENSEMBLES AGREE QUITE WELL WITH DEVELOPMENT AND

EVOLUTION OF AN AMPLIFIED AND STEADILY PROGRESSIVE MID-LATITUDE

FLOW PATTERN FROM THE ERN PACIFIC ACROSS THE LOWER 48 OVER THE

COMING HOLIDAY WEEK. THIS STORMY PATTERN WILL BE HIGHLIGHTED BY

THE INLAND SURGE OF DYNAMIC/COOLING/DESTABILILZING SHORT RANGE ERN

PACIFIC TROUGH ENERGY ALOFT OUT FROM THE INTERMOUNTAIN

WEST/ROCKIES THU OVER/THROUGH A MID-UPPER LEVEL MEAN RIDGE

POSITION BEFORE DIGGING/AMPLIFYING SEWD ACROSS THE CENTRAL US AND

INTO AN ERN SEABOARD BY CHRISTMAS. THIS SETS THE STAGE FOR

POTENTIAL FOR A SIGNIFICANT SWATH OF WINTER PCPN ACROSS THE NATION

AND LEADING TO WELL ORGANIZED HOLIDAY WEEKEND EAST COAST WINTER

STORM CYCLOGENESIS.

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