Winter 2019-20 Preseason Discussion

[frd]

Well you decide. 

Personally I can see a shot gun of outcomes. 

What do you think? As HM states, a shoe-in for a warm December , right ? 

Only a couple mets I follow are going for a normal or colder December.  

  

 

 

 

 

[frd]

I post the positives and negatives - for those that wonder why -  simply to make sure I am not biased cold and snowy. I love snow, but I attempt to be more realistic as I age.  

Chatting with bluewave about this November,  just like last November we are doing great in terms of almost record high NH snow cover.  I use to think that was awesome. 

What was viewed before as a great signal to a colder winter ( Judah  SAI)  has waned. We lost the snow last December and might lose the snow again this December if the warm December forecasts are correct. 

The changing Pac along with lower sea ice and other features are acting to put down rapid snow cover in October leading into November only to fall back versus above normal values in December.

Damn I hate looking at those maps. 

from bluewave: 

<<<

The cold November followed by a mild December has been a very persistent pattern this decade. So the snow extent charts are just reflecting this new regime.

 

 

     >>>

[Maestrobjwa]

1 hour ago, psuhoffman said:

He isn't saying it's going to be like last year, he is saying its going to be much much worse.  

Eh come off it...I see there ain't no reversing the effects of my posting from last year, smh (y'all are making me regret that more and more--I'm just moving on from it) 

I ain't off the handle on this, I'm telling ya...just waiting and seeing, fine-tuning expectations just like the rest of you. I mean...I know I ain't the only one here who loves snow and of course would love to see anything positive that might signal better chances, and not so much those things that signal not-so-good chances. Slowly learning the history of our hits and misses...and how erratic it can be year-to-year.

Yeah I love snow and yeah I wanna know our chances long before they come...so what? Why some seem to keep trolling me about it I have no idea. We all (or most of us) love snow here...

[Scraff]

For anyone interested, here is the Fox 5 DC winter outlook. Sure. I’d sign up for it.

 

https://www.fox5dc.com/weather/2019-2020-dc-winter-forecast-periodic-polar-vortex-visits-to-bring-waves-of-brutal-cold-more-snow-to-dc-region

[psuhoffman]

2 hours ago, Maestrobjwa said:

Eh come off it...I see there ain't no reversing the effects of my posting from last year, smh (y'all are making me regret that more and more--I'm just moving on from it) 

I ain't off the handle on this, I'm telling ya...just waiting and seeing, fine-tuning expectations just like the rest of you. I mean...I know I ain't the only one here who loves snow and of course would love to see anything positive that might signal better chances, and not so much those things that signal not-so-good chances. Slowly learning the history of our hits and misses...and how erratic it can be year-to-year.

Yeah I love snow and yeah I wanna know our chances long before they come...so what? Why some seem to keep trolling me about it I have no idea. We all (or most of us) love snow here...

I wasn’t kidding. I suppose I was being a bit flippant in how I said it. But if you read Isotherms winter outlook he is basically saying we will have a Nina like regime with above normal temperatures and below normal snowfall and a very hostile base state for snow here. The pattern he described was not like last year, it’s significantly worse.  I suppose if you only look at the raw snowfall expected for Baltimore it’s close but Baltimore was a local snowfall minimum last year with more snow throughout most of our region north/south/west of the city.  That’s just bad luck. Regionally we had a near normal snowfall winter last year. Isotherm is predicting a warm below avg snow winter for the whole east south of New England!  Not the same.

[Isotherm]

16 hours ago, frd said:

Wow,  this is a huge surprise,  and then again not so surprised.   

I value your research and insights, thanks for the time in putting this together @Isotherm

Personally I feel we do a generally normal winter but we can revisit this in later March. 

Isotherm's Winter Forecast 

http://www.lightinthestorm.com/

 

 

Much thanks for the kind words, @frd. I realize this is not a popular forecast, and as much as I would have 'wanted' to forecast the alternative, the objective data simply did not allow it. In my opinion, the case is a robust one for the statements opined in the outlook. As usual, it will be interesting to watch evolve. 

[Isotherm]

57 minutes ago, psuhoffman said:

I wasn’t kidding. I suppose I was being a bit flippant in how I said it. But if you read Isotherms winter outlook he is basically saying we will have a Nina like regime with above normal temperatures and below normal snowfall and a very hostile base state for snow here. The pattern he described was not like last year, it’s significantly worse.  I suppose if you only look at the raw snowfall expected for Baltimore it’s close but Baltimore was a local snowfall minimum last year with more snow throughout most of our region north/south/west of the city.  That’s just bad luck. Regionally we had a near normal snowfall winter last year. Isotherm is predicting a warm below avg snow winter for the whole east south of New England!  Not the same.

 

There were quite a few strong similarities to last autumn/preceding period in the objective data. As far as the major drivers, the disparities are not significant, though there are a couple notable differences. For example, the momentum budget tended a bit more positive last winter, which aided in the DC area occasionally striking luck with snowfall. With a stronger negative momentum signal this year, the snowfall regime may be less favorable than last through the first half. However, the descent of the easterly shear stress is an improvement over last year, which should, a priori, yield a more conducive regime for those on the East Coast south of Boston for February-March compared to last year. So there is a bit of balancing of positives/negatives of this year vs. last year.

[frd]

 

Something to keep an eye on during the next few weeks, as it appears to be an interesting set-up .

 

 

[frd]

@poolz1

You might enjoy this link. There is even a bias corrected  45 day CFS-v2 U10-60 forecasts. Pretty neat! 

 

 https://simonleewx.com/polar-vortex-forecasts/

 

 

 

 

[Ralph Wiggum]

5 minutes ago, frd said:

 

Something to keep an eye on during the next few weeks, as it appears to be an interesting set-up .

 

 

The interesting part is the SPV seems to be strengthening BUT the TPV is forecast to take a heck of a beating and split in 2 if not 3 by 240 hours. That bubble ridge over the N Atl at the 10hPa layer is wreaking havoc on the forecasting of PV imho.

[frd]

2 minutes ago, Ralph Wiggum said:

The interesting part is the SPV seems to be strengthening BUT the TPV is forecast to take a heck of a beating and split in 2 if not 3 by 240 hours. That bubble ridge over the N Atl at the 10hPa layer is wreaking havoc on the forecasting of PV imho.

Yes, that is true for the Atlantic , Matt posted on that earlier.  HM posted weeks ago about the coming wave breaking events.  

Here you go - 

 

 

[Ralph Wiggum]

3 minutes ago, frd said:

Yes, that is true for the Atlantic , Matt posted on that earlier.  HM posted weeks ago about the coming wave breaking events.  

Here you go - 

 

 

I'm confident the PV gets a beat down and splits, but not because the GFS says so. I am using solar data as well as SSTs in the N Atl, hemispheric snow coverage, and simplistic recent tendencies. Guess we wait and see what happens and if it is something that might show continuation through late Nov into Dec and down the line.

[CAPE]

Reading Isotherm's winter forecast reminds me of this..

 

 

[frd]

5 minutes ago, C.A.P.E. said:

Reading Isotherm's winter forecast reminds me of this..

Priceless !!!!!!!!!! 

I almost needed the Heimlich maneuver as I watched this while eating my dinner . 

 

[CAPE]

Just now, frd said:

Priceless !!!!!!!!!! 

I almost needed the Heimlich maneuver as I watched this while eating my dinner . 

 

It's a classic. Fun to show to my students, who are engineers. They love it.

[poolz1]

2 hours ago, frd said:

@poolz1

You might enjoy this link. There is even a bias corrected  45 day CFS-v2 U10-60 forecasts. Pretty neat! 

 

You know, I saw this tweet this morning and thought I would check it out this evening.  Honestly, I would have completely forgotten about it if not for this reminder.  Much appreciated! 

[frd]

Heard that BAMMWX is entering warmer risks into December,  but what I also heard was they mentioned the +IOD a a means of possibly lessening the warmer phases of the MJO we are destined for in December. 

Then this evening I saw something online by DT stating it was good news that in December the highly + IOD is forecasted to weaken. 

Hmm, I need to think about that more.   

WXRISK.COM    23h

 

A good point about the positive IOD. The good news for winter wx lovers is that it looks like the IOD breaks down pretty significantly in December

 

 

 

[frd]

Something else to ponder. A +PDO versus the Victoria mode.

You can see the image at the bottom for a representation of the associated SST anomaly . 

I need to research this more. Maybe Bob can chime in on this. 

To me the Victoria mode looks like a + PMM a little .  

I refer you to this 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014JD022221

 The Victoria mode (VM) represents the second dominant mode (empirical orthogonal function, EOF2) of North Pacific variability, independent of the Pacific Decadal Oscillation and is defined as the EOF2 of SST anomalies in the North Pacific poleward of 20°N. The present study indicates that the VM is closely linked to the development of El Niño–Southern Oscillation (ENSO). The VM may effectively act as an ocean bridge (or conduit) through which the extratropical atmospheric variability in the North Pacific influences ENSO. 

[psuhoffman]

20 minutes ago, frd said:

Something else to ponder. A +PDO versus the Victoria mode.

You can see the image at the bottom for a representation of the associated SST anomaly . 

I need to research this more. Maybe Bob can chime in on this. 

To me the Victoria mode looks like a + PMM a little .  

I refer you to this 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014JD022221

 The Victoria mode (VM) represents the second dominant mode (empirical orthogonal function, EOF2) of North Pacific variability, independent of the Pacific Decadal Oscillation and is defined as the EOF2 of SST anomalies in the North Pacific poleward of 20°N. The present study indicates that the VM is closely linked to the development of El Niño–Southern Oscillation (ENSO). The VM may effectively act as an ocean bridge (or conduit) through which the extratropical atmospheric variability in the North Pacific influences ENSO. 

Ugh I hate this crap. Let’s fight about exactly how to term something. Bottom line is the last few +VM winters were good pacific driven patterns so their linguistic victory of definitions seems pointless. And a +VM isn’t a -PDO more a slightly positive one. Both November 2002 and 2013 were good north pac sst matches and both features great pac driven winters following. We will see. I’m not saying that’s what’s coming just that I don’t know what Furtados point is here. 

[WxUSAF]

I hope Victoria’s Secret is lots of snow.

[Maestrobjwa]

11 hours ago, psuhoffman said:

He said that during the solar decline before the minimum the NAO trends more positive, and if we look at the last few cycles the winters leading up to the minimum did feature mostly +AO/NAO winters.  

Question: Was 2008/09 +AO/NAO? I ask because the sites I've read so far detailing approximate dates of past solar minima have placed the last one in late 2008. Of course that winter wasn't much good...yet the next one obviously was (and that particular time to historical degree, lol). Now, is a possible "lag" effect from the solar minimum part the reason we saw a great -AO/-NAO...or was that just coincidence? And overall...you could say the last three solar minimums we did benefit from, it seems (you could say the last four if you count 77/78--but the minimum came in 76)

[psuhoffman]

26 minutes ago, Maestrobjwa said:

Question: Was 2008/09 +AO/NAO? I ask because the sites I've read so far detailing approximate dates of past solar minima have placed the last one in late 2008. Of course that winter wasn't much good...yet the next one obviously was (and that particular time to historical degree, lol). And yet, the next winter was epic. Now is a possible "lag" effect from the solar minimum part the reason we saw a great -AO/-NAO...or was that just coincidence? And overall...you could say the last three solar minimums we did benefit from, it seems (you could say the last four if you count 77/78--but the minimum came in 76)

From my memory 2009 was a pretty neutral NAO year. It was also a weak Nina following a strong Nina in 2008. I also seem to remember some decent cold periods that winter that just didn’t produce much snow. Typical cold dry Nina stuff. But even so maybe some bad luck not to do a little better wrt snow that year. 

[Bob Chill]

15 hours ago, frd said:

Something else to ponder. A +PDO versus the Victoria mode.

You can see the image at the bottom for a representation of the associated SST anomaly . 

I need to research this more. Maybe Bob can chime in on this. 

To me the Victoria mode looks like a + PMM a little .  

 

I don't have much to say about "Victoria mode" as I've never paid any mind to it. Right now the Pac basin is ambiguous irt the PDO. If this was say mid Dec or later I wouldn't like what I see at all. However, this transition time of year can drop some clues and what I'm seeing over the next several weeks is a favorable pattern from Japan to the central pac basin to shuffle SSTAs around towards +PDO. Based on the warm anoms in the eastern npac near Japan, there's a good bit of work to do to get things looking more promising. Next couple weeks look decent but it's going to take more than a couple weeks to get a legit +PDO. 

[frd]

13 minutes ago, Bob Chill said:

I don't have much to say about "Victoria mode" as I've never paid any mind to it. Right now the Pac basin is ambiguous irt the PDO. If this was say mid Dec or later I wouldn't like what I see at all. However, this transition time of year can drop some clues and what I'm seeing over the next several weeks is a favorable pattern from Japan to the central pac basin to shuffle SSTAs around towards +PDO. Based on the warm anoms in the eastern npac near Japan, there's a good bit of work to do to get things looking more promising. Next couple weeks look decent but it's going to take more than a couple weeks to get a legit +PDO. 

Agreed. Seems Isotherm's sticking point, or one of several, was the PDO and the general Pac.  ( And, I do acknowledge he did say Feb and March might be good for our area, but not good enough to get us above his snowfall projections )  

I hope we get the changes you are talking about. 

It would be ironic if we time the STJ and the cold even for a week correctly, and then one storm alone can have a huge impact on the seasonal snowfall totals . aka  Jan 2016. 

 

[Bob Chill]

1 hour ago, frd said:

Agreed. Seems Isotherm's sticking point, or one of several, was the PDO and the general Pac.  ( And, I do acknowledge he did say Feb and March might be good for our area, but not good enough to get us above his snowfall projections )  

I hope we get the changes you are talking about. 

It would be ironic if we time the STJ and the cold even for a week correctly, and then one storm alone can have a huge impact on the seasonal snowfall totals . aka  Jan 2016. 

 

TLDR: way too early to expect or rule out any outcome this winter 

 

If you look at all current data objectively the sum points towards a rather boring winter. Nothing screams cold and/or snow and everything is at least whispering to not expect great things. But it's Nov 8th and the next 7 weeks or so is the window that most often throws a curveball at seasonal forecasters. Just as lack of blocking has baffled many over the last 5+ years, who's to say that a roaring -AO doesn't lock in during Dec/Jan? Or the Pac jet base state won't setup highway lanes that roll up and over the top of a PNA ridge and dig down to the gulf? These things have proven to be extremely difficult to forecast with any accuracy at 1+ month leads during enso neutral years. 

Dec is notorious for having a persistent longwave pattern upstream. And it's shown us many times that the persistent pattern in Dec likes to repeat throughout at least a portion of met winter. Do I think I know what kind of persistent pattern may set up in Dec? Nope, I really have no thoughts on that at all yet but I'll be watching things close AF as we roll through the second half of Nov. Dec could be quite variable with no recurring theme or it could tip winter's hand. Won't be too long before some clarity shows up there. 

Sometimes it's more of a timing issue versus a blown seasonal forecast. Like last year when it finally "got right" it was simply too late. Think about how bad d10-15 ensembles and CFA/EPS weeklies did last year? They ALL kept showing the same good thing run after run but the atmosphere didn't oblige until it was too late. The unexpected pac jet pattern in Dec-Jan basically committed felony larceny for 8+ straight weeks. That took every single wx enthusiast, professional, and weather supercomputer by surprise. What if the opposite happens this year and we "luck into" a nice longwave pattern even though the signs and data says we shouldn't? How can you confidently rule that out considering how many "surprises" winter has delivered over the years? 

I've only just recently started to see things that may break in our favor but my expectations are still pretty low and I'm fully prepared for an underwhelming snow season. The most promising thing that's happening in real time is the AO. Ens forecast over the next 2 weeks take it as low as -4. I have to dig around my files to find it but I did do a Nov AO analysis not too long ago. Having a mean -AO of at least 1sd below normal in Nov does correlate with a -AO during Dec and Jan. I have no idea if this winter will be blocky or not but seeing a pretty stout -AO in Nov is never a bad thing. If the PDO region starts setting up a +PDO as we close the month out that's not a bad thing either. 

 

[psuhoffman]

@frd @Bob Chill

 I had already looked at the PAC SST patterns from similar fall seasons in preparing my "thoughts" for the winter so it was easy to go back and look at some of the data I saved after that post last night regarding the EOF2 VMI.  Often its difficult to differentiate, its not always linear in progression and often the SST anomalies are ambiguous and not purely in a classic PDO or VM state.  It can also be difficult if you look at the whole basin and every little anomaly, but if we only look at the locations of the greatest warm and cold anomalies and adjust for the warmer base state of the whole pacific today, the 6 closest matches to the fall pacific SST pattern since in the last 35 years are 1986, 1989, 1993, 2002, 2004, and 2013.  All of them had a period in either October or November where the central and north pacific SST pattern looked very similar to now wrt the location of the warm and cold pools.  1986 and 2002 evolved into a more classic +PDO look by January.  1989, 2004, and 2013 remained in a EOF2 VM state through winter.  1993 evolved into an ambiguous look somewhere in between the EOF2 and PDO SST pattern for January/February of 1994.  

Here is the thing... both sets are too small to draw concrete conclusions...but both contain blockbuster winters and more mundane ones.  But neither of those sets contains a dud crap winter.  So I am not really sure what application we can even use from this war over exactly what classification the PAC base state is right now.  Frankly the outcomes of a fall EOF2 VM state are BETTER than the ones for all the fall +PDO years.  There are some blockbusters there also but there are some really awful crap years in that set as well.  So Furtado is correct the current PAC SST is technically a EOF2 VM NOT a +PDO however he seemed to be using that fact to argue against DT about a cold winter coming and I see nothing to support that application.  

Overall, and I hope to have my thoughts finally written up today or tomorrow, one common theme I am finding as I identify sets of "similar" years based on different factors...is a lack of total dud years.  They definitely aren't all good/great but the range on most of these factors seems to be between a mediocre near normal year and a good year...not a lot of examples of bad crap years in the sets of similar years based on Pac SST, QBO, and Atlantic SST patterns.  There are also not a lot of good comp years to compare this year too with the same combo of factors so there is a lot of uncertainty and so we could have a crap year...but right now I feel comforted a little by the fact there there are not a lot of really bad winters in the different analog sets I have put together.  

[psuhoffman]

On 11/6/2019 at 2:45 PM, 40/70 Benchmark said:

Good analog, but not my number one. Later onset should have ramifications this season.

Was 1989-90 in your analogs?

[Bob Chill]

@PSU

It's a tough year with no "easy" signal basically anywhere. Everything from top to bottom looks right in between good and bad to my eyes. 

 

[Bob Chill]

You guys keep hearing me talk about a +PDO so here's a quick visual post to make it easier to understand if you're not familiar with the PDO region and what is good and bad etc...

Here's a textbook +PDO.

Nino years almost always feature a +PDO because warm enso coincides with BN SSTs in the werstern side of the north Pacific. However, a +PDO during enso neutral years is not as common and it's a net positive as shown in my previous post with enso neutral/+PDO years. 

Right now the npac basin is right in between a + & -PDO. Basically ambiguous. 

 

The blue circle is the area to watch. There's plenty of work to do as the + SSTA's near Japan are pretty damn warm. But the trend in general since Sept is slow cooling of the region. The eastern side of the NPac already looks good. 

Here's why I think the trend towards a potential +PDO will continue. Over the next 2 weeks the height patterns and surface temps are prog'd to be below normal for most of the period in the west NPac at the same time the PNA will be turning positive. Between the PNA ridge in the east and the persistent troughing in the west, it's reasonable to expect SSTs to continue to cool in the western region and warm near the coast of north america. 

 

2 weeks isn't long enough magically fix everything and have a classic +PDO. It takes a lot of energy to bully ocean SSTs. It is encouraging seeing a good longwave pattern in the Pac for the next few weeks and just hope it continues all Nov into Dec. If it does then my guess is the early winter pattern may be showing its hand in a good way. 

 

 

[Jebman]

Its going to be cold as hell is hot, all over. Even south central Texas where I reside has been cold as fook! I'm not even used to this anymore lmao! Buda TX is supposed to be in the upper 30s FOR HIGHS next Tuesday! Our normal LOW, is 53! Thats 36 degrees below normal! Its not the first time this season. Something is deranging the North American weather pattern this fall/winter, in a good way. Forecasters down here are even beginning to talk of a Pacific disturbance interacting with next weeks' Siberian Front, possibly bringing wintry weather here in Buda! IN NOVEMBER! That has a hard time happening down here in January! My uncle lives up in Wisconsin, they hit -4 already one night! Thats REAL COLD for them this time of year.

The Mid Atlantic is going to be totally obliterated this winter, by ridiculous frigid values and by near record, to outright record snows! You better get your snowblowers, Jebman snow shovels, ice melter and snowmobiles NOW, or else get down to Cancun, while you still can!