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Winter 2020-2021


ORH_wxman
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4 minutes ago, michsnowfreak said:

Call me weenie, but I can't shake that 2007-08 feel. A dry Fall and as we get closer to winter its getting stormier.

Oct 2007 was an absolute furnace though....so big difference in the CONUS pattern where 2020 will likely finish below normal for a chunk of the plains and midwest/lakes. Prob will still finish above normal here in the northeast as we're going to be east of the best cold over the next 10 days.

 

But that doesn't mean winter can't be similar. There are definite similarities elsewhere and in the tropical PAC.

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Just now, ORH_wxman said:

Oct 2007 was an absolute furnace though....so big difference in the CONUS pattern where 2020 will likely finish below normal for a chunk of the plains and midwest/lakes. Prob will still finish above normal here in the northeast as we're going to be east of the best cold over the next 10 days.

Very good point. not getting out of the 40s here today, should finish cooler than avg in Oct.  Another difference is we've been at peak color this past week, 2007 was a late peak, not until late October and even early November (im sure the warmth helped).

 

But I still can't shake that feel of 2007-08. I may be dead wrong, I just hope I am not. It was a nonstop parade of storms. It was no 2013-14 with a record snowpack because we had multiple thaws, so even 2007-08 certainly had its imperfections, but im riding the stormy bus til it crashes lol

 

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I posit some of the issue with NINA anomalies ( perceived as such...) may be because the easterlies are entering a new climate paradigm, where they are stronger ... 

In this idea, these lower latitude mass flux anomalies are a compensating for the general large scale circulation that is featuring ( empirical at that ... ) mid latitudes jet velocity anomalies that are integrating a faster planetary troposphere in the westerlies ...  Conservation has to diverge that flow some where, some how - propose ..some goes N; the rest goes S. 

And in the latter sense, that mass ends up arcing back west into the trade belt. This positive flux sourcing is augmenting the easterlies. I'm just not sure if this is cartoon/ACME Industries logic ( b-bunny road-runner reference :) ) ... but, so long as large Coriolis torque is balanced and the mass motion is not exceeding that force - I don't see how it that explanation can be dismissed out of hand. 

If that hypothesis is true ... it's not then a tremendously difficult leap of insight to suspect sea-surface stressing from the east is also enhancing ...as a base-line state. And the latter bold is crucial as a distinction between it, and the La Nina - which it can certainly mimic/cast off that impression of La Nina.  Compounding further, there may in fact "BE" a concurrent La Nina super synoptic forcing in play - the former hypothetical would thus [ probably ] constructively interfere and enhance the illustration of it - 

... But not seeing aspects of La Nina behave the way they should, may be betraying that a weak La Nina is really what is there ...if perhaps getting dressed up to be something more than it is by the effects of a "new" base-line of strengthening lower tropospheric easterly trades.   

fascinating - ... But this same effect may also account for why recent El Ninos haven't been presenting as proficiently in global patternization of the westerlies/R-wave distribution as it has notably across many decades of the past ( prior to ~ 2000... ).  No...it's not 0 - as in not observable at all...just an attenuation and lowering of the expectation/somewhat failure along typical climate pathways. 

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17 minutes ago, 40/70 Benchmark said:

Its around average, I think...which makes sense.

2 out of 3 of those had the potential to go very big.  1999-00 was a 2nd year Nina which kind of throws a potential wrench?  2007 and 1970 had great Decembers.   1999 had a bad December.

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2 hours ago, weathafella said:

2 out of 3 of those had the potential to go very big.  1999-00 was a 2nd year Nina which kind of throws a potential wrench?  2007 and 1970 had great Decembers.   1999 had a bad December.

I don't value you that as much as some do...I know raindance is big on that. But again.....just because I incorporate an analog does not mean I endorse it 100%. A concept I wish people could grasp more assertively with respect to politics.

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https://longrangesnowcenter.net/2020/10/20/october-preliminary-2020-21-winter-outlook/

An interesting splash of factors, for the Eastern US, a few shifts (particularly on ENSO) from last time I dropped in:

  1. A basinwide moderate (possibly strong) La Nina this winter. 
  2. A positive QBO 
  3. Solar Minimum 
  4. Atlantic SSTs favourable for a +NAO 
  5. North Pacific SSTs favourable for a Aleutian Ridge. 
  6. Average growth of Stratospheric Polar Vortex into winter, potential for SSWs later. 
  7. Phase 3-6 MJO centred tropical base state 
  8. Low sea ice in Barents-Kara Sea. 
  9. Average snow coverage in Siberia. 

Looking at a slightly above average snowfall season for New England IMO.

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mM... Something strange is going on in the QBO though. I'm suspicious of using that metric as a leading 'clean' or coherent indicator (statistically) for the SSW stuff... for that matter, the overall (+)(-)AO tendencies. 

It's tough - we are statistically in the 2 to 3 year gap and these cavities in SSW activity typically load-in in these windows, but having the QBO now flopping around for the first time in history - uh... This obviously caveats the indicators. One argues we are likely to get a warm wave event or two this winter; while the other has broken down.  I don't think this latter aspect can be skipped over in any usage or attempt to use the QBO - 

The easterly phase of the QBO is somewhat more correlated to the advent of short, sharp, clean and (crucially) downward propagating warming events - the latter aspect being important in the time-lag -AO mode.  When the warming leading to the ensuing -AO take place, the mode can last just a couple of weeks, or the rest of the hosting winter season - there are examples of variable length once the -AO kicks in. 

So what's up with the QBO ? 

The regular 24 to 36 month periodicity spanning the last 70 years of the observations has recently twice failed for the first time(s).  In plain English ... the QBO reversed when it should not have. And by that, the predictable nature of timing the oscillation/reversal in top-down modeling was thrown out of whack ..certainly is a 'woah' moment, rattling confidence of the QBO as a dependable indicator. 

What/why it broke down?  ...enter supposition here [      ]   

But, this 2nd event appears to be taking place now... The previous was back during 2015-2016 winter ... However, that event shows up as a greater numerological variance, swinging hugely from positive to negative phase with little or no warning.  Right now...this is appears to be taking place more subtle... with variance at shallower in absolute values:    https://psl.noaa.gov/data/correlation/qbo.data

Also...as an afterthought, there is a bright correlative relationship in the data between the MJO phases and the AO... MJO "might" even be used as an apparent leading mode of the AO... whereby the phase 2 thru 6 that are strengthening tends to lead the onset of the +AO, and vice versa on there other side of the phase diagram . This is thought to be the case because 2-6 tend to correlate with stronger subtropical ridging ...and that strengthens the westerlies over top where the circulation join the westerly main mass transport... Thus torque balancing --> weakens cyclogenesis at middle latitudes.  Contrasting, the other side... robuster cyclogenesis results, increasing the ambient lower Ferrel Cell easterly trades in the lower boundary of the winter-time PV ( 45 to 70 N) ...and that means the the PV is being stressed/weakens... a.k.a -AO.  I personally believe the recent observations wrt to the HC also play a role in enhancing the +AO, because: .. intuitively, the 2-6 phases of the MJO are probably getting a large/super synoptic scale constructive interference pattern by the current +HC ...  which offers an early clue as to +AO winter ... experimental.  Which is interesting, because the solar minimum going back hundreds of years of reanalysis ..certainly correlates reasonably well if not fantastically so, with the -AO ...again...we're stuck with diametric signals here.  

With the QBO acting flakey in an unprecedented way... the AO being stuck positive during an opposing solar mimimum correlation that has been pretty sterling as a -AO correlation ( but is not..>) ... and the HC ... plausibly if not likely muting some of the ENSO effects due to smothering gradient dispersal inside the HC boundary ...etc... 

The snarky cynic in me thinks this winter is a big huge steaming pile of CRAP shoot...and throwing enough shit against the wall is going to make someone look like an "accidental" genius

But then I recollect and gather around some form or hope of rationalism and simply state that ... it's fair to question the hitherto "traditional" institution of correlations, because the geophysical dynamics are changing, and that " synergistically" is altering world right before our eyes ... 

But it's all supposition and tongue in cheek,...  I'm not here to refute or impugn anyone's effort - just fwiw ... But there is truth in these concerns

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10 minutes ago, powderfreak said:

Nice Ray, I like that format of having those instead of integrated in the actual outlook.

It was just too tedious the other way. I feel it distracted people from the point of the whole damn exercise, which to to convey my thoughts as to how the ensuing winter will evolve. However, the guys like @HoarfrostHubb, who like the foundational material, can simply clink the link.

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20 minutes ago, ORH_wxman said:

Moderate Nina....looks like we will continue to see the colder subsurface rise to the surface in central and eastern areas with the easterly wind bursts continuing.

 

Oct15_TdepthAnomaly.thumb.gif.7c14241f2f2dafdf6c9d0babfc2e96b4.gif

 

 

 

Yes. Agree....this is why we can take the CP la Nina conceptualization off of the table IMO, which is good news. However, it is already basin wide, so we can't really dub it an EP event, either....not so great.

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2 hours ago, 40/70 Benchmark said:

Yes. Agree....this is why we can take the CP la Nina conceptualization off of the table IMO, which is good news. However, it is already basin wide, so we can't really dub it an EP event, either....not so great.

I was going to ask that. People keep calling this “east-based” but it’s really basin-wide. ENSO region 4 hasn’t been this cold in over a decade and the models project it to stay that way throughout the winter. It’s approaching -1.0C: nino4.png

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20 minutes ago, snowman19 said:

I was going to ask that. People keep calling this “east-based” but it’s really basin-wide. ENSO region 4 hasn’t been this cold in over a decade and the models project it to stay that way throughout the winter. It’s approaching -1.0C: nino4.png

You are correct. Very important point that some are missing. And there is a difference. This is going to a central theme of my outlook...my composites are all done, and I'm just starting the narrative portion.

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On 10/16/2020 at 9:29 AM, Typhoon Tip said:

James .. they may vary slightly (or not...) from agency to agency but the Climate Diagnostic Center labels them as:

Pacific North America Pattern (PNA) [(15-25N, 180-140W)-(40-50N, 180-140W)+(45-60N, 125W-105W)-(25-35N, 90W-70W)]

North Atlantic Oscillation(NAO) [(35-45N, 70W-10W) - (55-70N, 70W-10W)]

Western Pacific Oscillation(WPO) [(25-40N, 140E-150W) - (50-70N, 140E-150W)]

Eastern Pacific Oscillation(EPO) [(20-35N, 160W-125W) - (55-65N, 160W-125W)]

(Couresy: https://psl.noaa.gov/forecasts/reforecast2/teleconn/ )

However, any variances between agency definitions would likely not reflect a difference in correlation significance - meaning...doesn't really matter.  

Note, due to the recent upgrades in the GEFs ensemble system, CDC's coverage/calculations necessarily need to be reconstructed; however, I shared a correspondence with personal at that office recently who indicated that there is no present funding for such an operation - therefore, public URL access to CDC - derivatives is discontinued pending further notice.  Nevertheless, these are the domain spaces that were employed for the GEFs, and though I cannot confirm this with certainty .. it is likely that any new system won't change these geographical areas - it is the data density that is the cause for the product suspension and revamp necessity.   The ECMWF and/or UKMET ( super blend..etc) may or may define their domain regions the same way. 

thanks Tip

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