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

 

Southeast U.S.:

I project the prospects for snow and ice threats and storms (quality and quantity) to be slightly below normal this winter.  The projected Dec pattern could be promising.  Thereafter, we should see some periods in Jan and Feb where arctic air is dislodged into the U.S. via the poleward N Pac high.  The mean storm track should be consistently to our NW, a limiting factor.  I would expect fewer than normal storms traversing the deep south in the southern stream.  Of note, if we were to see a strongly negative NAO pattern develop this winter, a poleward N Pac high in concert with a -NAO is a pattern that has historically produced above average wintry precipitation in the SE.

[Cold Rain]

I love reading a Griteater winter forecast...usually.  This one, meh!  Haha good work man.  This is in line with my expectation, on balance.  Your Jan looks brutal, though.  I hope it's not quite that bad.  Anyway, good work sir!

[Brick Tamland]

You didn't say we would have an awesome winter with a foot of snow.

 

 

[nrgjeff]

Best match to my thoughts I've seen on the Board, esp overall charts. I like introducing the chance of a mild January, a real possibility. My February is warmer and my January is cooler, but perhaps Griteater is right. Since month-by-month is challenging this far out, I consider the whole package. I strongly agree with Griteater.

[griteater]

29 minutes ago, Cold Rain said:

I love reading a Griteater winter forecast...usually.  This one, meh!  Haha good work man.  This is in line with my expectation, on balance.  Your Jan looks brutal, though.  I hope it's not quite that bad.  Anyway, good work sir!

Thanks man.  The years are beginning to fly by on here....all in fun

 

21 minutes ago, Brick Tamland said:

You didn't say we would have an awesome winter with a foot of snow.

 

 

Maybe this is the year Brick...Raleigh is due for a biggie 

 

8 minutes ago, nrgjeff said:

Best match to my thoughts I've seen on the Board, esp overall charts. I like introducing the chance of a mild January, a real possibility. My February is warmer and my January is cooler, but perhaps Griteater is right. Since month-by-month is challenging this far out, I consider the whole package. I strongly agree with Griteater.

Thanks nrgjeff, it means a lot I can assure you.

[Brick Tamland]

Just now, griteater said:

Maybe this is the year Brick...Raleigh is due for a biggie 

 

I feel like we have been saying this for a while now. I do know we are past due as far as averages go for years between having a storm with more than 6 inches of snow. 

[yotaman]

I don't like this forecast. December is not a good time to get the cold weather. I would rather have a Jan and Feb below normal than a Dec.

[NWNC2015]

Don't quiet agree looks a little too optimistic...I think below normal precip will extend on up to DC in the mid Atlantic...and over more of the GOM regions (Texas/Florida). Above normal precip won't be in WV...think it will end up way west of there. Snowfall I think more of the West (northern Cali) will see above normal and I would watch Maine too in this pattern. February temps look odd I would go AB for the S/E at least slightly nothing favors near normal. 

And of course, with our average snow totals so low anyways we run the risk of above normal snow in the S/E from one storm so not worth mentioning/guessing. Nobody knows.

[Met1985]

Great work griteater !  Thank you for taking the time to put this together. 

[BIG FROSTY]

Great Job Grit! Thanks for taking the time doing it and posting so we can all CRY!!! j/k lol 

[Cold Rain]

I take it back, Grit.  Any forecast based on analogues before 2000 should be immediately discarded!!

[griteater]

1 hour ago, NWNC2015 said:

Don't quiet agree looks a little too optimistic...I think below normal precip will extend on up to DC in the mid Atlantic...and over more of the GOM regions (Texas/Florida). Above normal precip won't be in WV...think it will end up way west of there. Snowfall I think more of the West (northern Cali) will see above normal and I would watch Maine too in this pattern. February temps look odd I would go AB for the S/E at least slightly nothing favors near normal. 

You may have the right idea.  You should sketch it out and claim that bad boy, then talk junk when you get it right!

 

53 minutes ago, Met1985 said:

Great work griteater !  Thank you for taking the time to put this together. 

Thanks Met, I see you have my back over there on the main board...I like it!

 

41 minutes ago, BIG FROSTY said:

Great Job Grit! Thanks for taking the time doing it and posting so we can all CRY!!! j/k lol 

You got it man.  We all just want snow, so, we'll see

 

37 minutes ago, Cold Rain said:

I take it back, Grit.  Any forecast based on analogues before 2000 should be immediately discarded!!

Met1985 has my back, so it's all good!

[Met1985]

7 minutes ago, griteater said:

You may have the right idea.  You should sketch it out and claim that bad boy, then talk junk when you get it right!

 

Thanks Met, I see you have my back over there on the main board...I like it!

 

You got it man.  We all just want snow, so, we'll see

 

Met1985 has my back, so it's all good!

Lol that guy is jumping to huge conclusions .  The NE thread is having a go with him in there November thread currently .  Oh yeah Griteater I got your back! SE for life! lol.

[packbacker]

Well that sucks. #+NAO

 

[Snowless in Carrollton]

4 hours ago, yotaman said:

I don't like this forecast. December is not a good time to get the cold weather. I would rather have a Jan and Feb below normal than a Dec.

lol, December is one of our core winter months and our 2nd coldest winter month. I say bring on the cold in December. Plus, it's holiday season so it makes things feel more festive.

[Isotherm]

Repost from main board:

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. 

[Avdave]

this was well written Grit. Great job on it. Thanks for taking the time to put it together

[Daniel Boone]

The overall djf outlook looks alot like noaa's.  I would think the midwest(not just upper) and upper Ohio valley (even lower possibly) would have above normal snowfall with that pattern your outlook portrays.

[griteater]

15 hours ago, Isotherm said:

Repost from main board:

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.  I decided to post it over there as well this year though I'm concerned that mod and former school administrator jburns may call me in to his office for a discussion on duplicating posts across the board.

 

13 hours ago, Avdave said:

this was well written Grit. Great job on it. Thanks for taking the time to put it together

Thanks Dave!  Appreciate it.

 

13 hours ago, Daniel Boone said:

The overall djf outlook looks alot like noaa's.  I would think the midwest(not just upper) and upper Ohio valley (even lower possibly) would have above normal snowfall with that pattern your outlook portrays.

That could be.  I took the projected pattern and tried to envision where the most snowfall would occur each month...and then tried to see where they intersected.

[NCSNOW]

Great Job Grit:As always great explanations for the conclusions you presented:

My 2 cents are that the upslope regions will be the money spots this year in the SE in terms of reaching or exceeding their local climate seasonal averages. This will be a northern stream dominant pattern this winter. So lots of NW flow which will work out fine for folks on the other side of the hills but cause Brick alot of bad mood days cause he hates Cold & Dry. We will remember this winter for Cold and Dry. The warm or above avg days will be short 1-2 days stints ahead of an onslaught of dry cold fronts (thnx downsloping winds). Very progressive pattern which is also going to make any phasing problematic unless blocking occurs, which Ive learned never to depend on.