Griteater's Winter Outlook (16-17)

[griteater]

Griteater's Winter Outlook (16-17)

 

 

 

 

 

 

 

 

 

Parameters:

• Weak La Nina – I believe this will be an official Weak La Nina via SSTs, though it could be a close call.  VP and OLR patterns, and AAM numbers, all support the idea of a weak nina.  Although the MEI is in neutral conditions as of the Oct data, 7 of the 9 MEI parameters indicate emerging La Nina conditions.

   

• Nina Base – the Sep-Oct SST pattern is characteristic of a Central Pacific La Nina, and I would expect that to continue through winter.

 

Graphic below from Zhang et al paper

 

 

• QBO – positive through winter in the full 30mb to 50mb layer

   

• Solar Flux – has dropped into the range that is considered “solar minimum” values, and I would expect that to be the case through winter.

   

• Solar Cycle – still declining and won’t be in the section of the solar cycle considered “minimum” for another winter or 2.

   

• AAM – the July to October AAM average is in the -0.25 to -0.30 range.

 

• PDO - not decidedly positive or negative.  I favor a neutral PDO this winter.

 

 

Discussion Points:

 

December:

• Data I viewed for Dec favored a classic -PNA pattern of W U.S trough and E U.S. ridge.  However, IMO, current stratospheric parameters add complexity to the Dec forecast.  The Oct and modeled Nov stratospheric conditions favor an early winter -AO, as shown here - https://twitter.com/griteater/status/791381087868035072.  Not mentioned at that link is the modeled Nov temperature pattern in the stratosphere of warmer than normal temperatures over northern Russia and into the Arctic, also favoring an early winter -AO (both interrelated).

   

• The eastern U.S. was generally colder than normal in 10 of the 14 cases in which the AO was negative in Dec during weak cool ENSO events. 

   

• In the most recent Euro monthly run, the top ensemble cluster displayed a -AO pattern, W U.S. ridge, and E U.S. trough.  Also of note, the Euro monthly output was similar to the only 2 Central Pacific, Cool ENSO Decembers that had a -AO/-NAO pattern - https://twitter.com/griteater/status/791659654094917633

   

• Of the 4 Super Ninos on record, the 2 that got off to a cold start in the subsequent winter in the E U.S. were weaker cool ENSO and not as negative with the PDO, more similar to the current conditions:

Credit to Eric Webb (@webberweather) for his ENSO research prior to 1950.

 

• In spite of the forecasted -AO in Dec, the super charged Pac jet must relax before any widespread below normal temperatures can be realized in the E U.S.

 

 

January – March:

• My forecast favors a mostly -NAO for Dec into early Jan (and -AO), transitioning to a neutral to positive NAO for the remainder of winter.  Rationale follows:

   

• As covered in the earlier referenced paper from Zhang et al, a correlation exists between C Pac La Ninas and +NAO, especially in Jan – Feb

 

 

• The paper covers La Ninas between 1954 and 2008.  I have done my own research for all cool ENSO events since 1871 and found that the C Pac Cool ENSO to +NAO correlation exists in years prior to 1950 as well.  The correlation varies depending on the ENSO strength and the specific month.  Here’s the full list of C Pac years from my research with the NAO data:

 

• Per this Maliniemi et al paper, +NAO is favored during the declining phase of the solar cycle, owning to “a peak in geomagnetic activity and magnetospheric particle fluxes during the declining phase of the sunspot cycle.”

 

• And lastly, although the stratospheric polar vortex is weaker than normal this autumn, it is normal climo for the vortex to undergo strengthening through December (though that process is certainly on hold, at least for now).  The combination of +QBO and low solar flux is not a good one for mid-winter SSWs.  Per the FU Berlin data, in the 15 cases of +QBO and low solar flux, only 2 of the cases experienced a mid-winter SSW in Jan or Feb (there was a third case of a SSW in Dec).  In addition, when SSWs occur during La Ninas, a cold response isn’t common in the E U.S. as shown in this video from Levi Cowan.

 

• North Pacific Pattern for Jan-Mar: during cool ENSO winters, a high pressure ridge is strongly favored in the North Pacific mean winter pattern.  This is especially the case when the AAM averages negative during the summer to early autumn months.  Per the data, a N Pac high was present in the mean winter pattern in 25 of the 26 cases of cool ENSO combined with a July-Oct AAM that averaged negative.  When the JASO AAM averaged positive during a cool ENSO winter, a N Pac high was present in only 2 of the 6 cases (and the JASO AAM was barely positive in those 2 cases).  The JASO AAM average this year is in the -0.25 to -0.30 range, consistent with weak cool ENSO conditions.

   

• In terms of the N Pac ridge placement, Anthony Masiello’s findings show that a more poleward N Pac ridge is favored during +QBO/cool ENSO winters, while a more southerly placed N Pac ridge is favored during -QBO/cool ENSO winters.

[qr7121]

any forecast that uses analogs from pre-2000 should be automatically discarded... the notion that our current climate bears any similarity to that of the twentieth century is absurd (even pre-2010 at this point)

[FallsLake]

Great work grit! Very detailed but very understandable. **lets hope that higher amount of Siberian snow coverage can keep blocking going farther into January..

[qr7121]

1 minute ago, FallsLake said:

Great work grit! Very detailed but very understandable. **lets hope that higher amount of Siberian snow coverage can keep blocking going farther into January..

how is this great work? there is no analysis of cause and effect or mention of the record low sea ice... this is a prime example of why LR forecasting has become incredibly stunted as a field: people spit out a bunch of random indices and are then applauded for doing regression analysis. why not look at actual conditions (i.e., record NHEM snowcover, record low sea ice)? because when you do that, it is obvious that we have spun well out of our old climate and that the above forecast is literally garbage

[qr7121]

let's talk about how QBO and solar minimum are basically irrelevant to SSWs when you have huge areas of open water up to +5C above normal lingering in and around the Arctic... what analogs match this situation? none! lol

 

http://www.dmi.dk/uploads/tx_dmidatastore/webservice/0/e/5/2/6/581998ed625e0.png

[roardog]

36 minutes ago, qr7121 said:

how is this great work? there is no analysis of cause and effect or mention of the record low sea ice... this is a prime example of why LR forecasting has become incredibly stunted as a field: people spit out a bunch of random indices and are then applauded for doing regression analysis. why not look at actual conditions (i.e., record NHEM snowcover, record low sea ice)? because when you do that, it is obvious that we have spun well out of our old climate and that the above forecast is literally garbage

[qr7121]

why don't you provide some substantial rebuttal instead of a rolleyes?

why does the forecast not mention the below? LOL

 

 

unfortunately anomaly map is dated 10/2 but if anything it has gotten worse

 

[Met1985]

2 hours ago, qr7121 said:

how is this great work? there is no analysis of cause and effect or mention of the record low sea ice... this is a prime example of why LR forecasting has become incredibly stunted as a field: people spit out a bunch of random indices and are then applauded for doing regression analysis. why not look at actual conditions (i.e., record NHEM snowcover, record low sea ice)? because when you do that, it is obvious that we have spun well out of our old climate and that the above forecast is literally garbage

Where is your winter outlook before you call other people's research and work garbage bud. Yes we have record low sea ice. No kidding and there is recent research suggesting that because of the record low sea ice this helps with NH snow cover . 

[Bob Chill]

3 hours ago, qr7121 said:

any forecast that uses analogs from pre-2000 should be automatically discarded... the notion that our current climate bears any similarity to that of the twentieth century is absurd (even pre-2010 at this point)

 

Sounds like you are the resident expert on the "new normal". Looking forward to your forecast and rationale since apparently none of us know as much as you. 

 

 

[qr7121]

6 minutes ago, Bob Chill said:

 

Sounds like you are the resident expert on the "new normal". Looking forward to your forecast and rationale since apparently none of us know as much as you. 

 

 

the problem with the new normal is that it isn't a steady state and that since it is so new there are no experts... i will not issue firm forecasts beyond D45 or so except to say that snow totals this winter across the NE will be prolific and there will be large swings from record warmth to record cold. i anticipate new records in NYC and Boston and possibly Chicago/DTW as well. 

snow/cold begins 11/15-12/15 and current thinking is it resumes after 1/1 with a HECS ~11/25... the upcoming cold period is the result of a massive ridge building over the west coast which is imminently going to push NE into Greenland and force an ejection of a GAK airmass into NE North America... 

i think we see a repeat of this after the late December respite and the winter largely echoes 2010-11 but is substantially more severe in the cold parts

[Isotherm]

Grit -- very good write-up and research as per usual. Your scientific rationale is logical and cogent. I am studying many of the same indicators in developing my outlook as well. It will certainly be an interesting winter as I believe there are more contradictory signals than usual. If there is a bust, do you think the result will more likely be colder or warmer than your forecast? The autumn has featured a very impressive weakening of the vortex, but as you alluded to, some of the exogenous indicators aren't necessarily supportive of its maintenance. 

Good luck with verification. 

[Isotherm]

1 hour ago, qr7121 said:

the problem with the new normal is that it isn't a steady state and that since it is so new there are no experts... i will not issue firm forecasts beyond D45 or so except to say that snow totals this winter across the NE will be prolific and there will be large swings from record warmth to record cold. i anticipate new records in NYC and Boston and possibly Chicago/DTW as well. 

snow/cold begins 11/15-12/15 and current thinking is it resumes after 1/1 with a HECS ~11/25... the upcoming cold period is the result of a massive ridge building over the west coast which is imminently going to push NE into Greenland and force an ejection of a GAK airmass into NE North America... 

i think we see a repeat of this after the late December respite and the winter largely echoes 2010-11 but is substantially more severe in the cold parts

 

These are bold assertions, but without any scientific rationale, it is unsupported speculation. You accused grit of posting an outlook devoid of real analysis, but you provide no justification at all. All you've done is hijack the thread with your criticisms. 

[Bob Chill]

Sorry Grit for not responding properly earlier. The troll got the best of me. After seeing his response I know now that I don't need to further engage with the uneducated. 

Well presented thoughts and unbiased outlook. Of course I don't like it  but I can't disagree with it. The one thing that differs from my thoughts so far is I think Jan could be a continuation of the early winter pattern then the cancel switch comes in Feb and stays that way. My region has had a couple of memorable March's recently. My gut tells me that winter could fade by mid Feb (or even earlier) from 40N southward and March is a no-go. Which is pretty normal and hardly a gutsy call. 

If the December AO comes in @ -1.20 or lower then the odds of a continuation in Jan are fairly high. I'd post my spreadsheet but I can't find it right now.  Early signs seem to be setting up for the best chances at early blocking since Dec 09 & 10. The Pac will be wildcard of course. An -AO can be negated fairly easily like what happened 12-13 and 00-01. Time will tell. 

For the record, I'm expecting 75-100% of climo snow for the mid atlantic. Even that could be too bullish. Just a hunch that I can't shake. 

[Met1985]

53 minutes ago, Isotherm said:

Grit -- very good write-up and research as per usual. Your scientific rationale is logical and cogent. I am studying many of the same indicators in developing my outlook as well. It will certainly be an interesting winter as I believe there are more contradictory signals than usual. If there is a bust, do you think the result will more likely be colder or warmer than your forecast? The autumn has featured a very impressive weakening of the vortex, but as you alluded to, some of the exogenous indicators aren't necessarily supportive of its maintenance. 

Good luck with verification. 

Isotherm let us know when you put your outlook out . Its always a pleasure reading your thoughts along with griteater . 

[griteater]

21 hours ago, FallsLake said:

Great work grit! Very detailed but very understandable. **lets hope that higher amount of Siberian snow coverage can keep blocking going farther into January..

Thanks Falls, appreciate it.

 

16 hours ago, Isotherm said:

Grit -- very good write-up and research as per usual. Your scientific rationale is logical and cogent. I am studying many of the same indicators in developing my outlook as well. It will certainly be an interesting winter as I believe there are more contradictory signals than usual. If there is a bust, do you think the result will more likely be colder or warmer than your forecast? The autumn has featured a very impressive weakening of the vortex, but as you alluded to, some of the exogenous indicators aren't necessarily supportive of its maintenance. 

Good luck with verification. 

Thanks Iso, those are kind words.  Regarding your question, there are a lot of scenarios that go thru my mind, but the one that stands out is just how warm it has been since March.  Record warm temperatures have been so 'easy' to attain across N America.  The image below from Mar-Oct is quite remarkable in that there are just 2 little specs of below normal heights over the entire N Hemisphere.  Can it get cold this winter, sure...we are seeing a lot of cold deposited into Eurasia at the moment...but the warm background is there lurking.  I did build a bit of this into my outlook, but not a ton.

 

16 hours ago, Bob Chill said:

Sorry Grit for not responding properly earlier. The troll got the best of me. After seeing his response I know now that I don't need to further engage with the uneducated. 

Well presented thoughts and unbiased outlook. Of course I don't like it  but I can't disagree with it. The one thing that differs from my thoughts so far is I think Jan could be a continuation of the early winter pattern then the cancel switch comes in Feb and stays that way. My region has had a couple of memorable March's recently. My gut tells me that winter could fade by mid Feb (or even earlier) from 40N southward and March is a no-go. Which is pretty normal and hardly a gutsy call. 

If the December AO comes in @ -1.20 or lower then the odds of a continuation in Jan are fairly high. I'd post my spreadsheet but I can't find it right now.  Early signs seem to be setting up for the best chances at early blocking since Dec 09 & 10. The Pac will be wildcard of course. An -AO can be negated fairly easily like what happened 12-13 and 00-01. Time will tell. 

For the record, I'm expecting 75-100% of climo snow for the mid atlantic. Even that could be too bullish. Just a hunch that I can't shake. 

It's no problem Bob.  I enjoyed hearing your thoughts on the winter as well...they make sense.

[WXinCanton]

Nice work Grit, thanks for sharing.