Winter 2019-20 Preseason Discussion

[frd]

This will be interesting to track in the months ahead. 

I know several mets who are very interested in the QBO and the impact it may have on the upcoming winter.  

 

 

[frd]

This is a great thread to read.  Really does seem things are coming together for a Modoki Nino . 

 

 

[frd]

From a met at 33andrain 

 

Posted 15 hours ago

To piggy-back off of the above posts...The analogs that end up blockiest over the course of the winter have an Aleutian low and Niño-like tropical forcing in the fall.   With the recurving Tyhpoon (coincident with a strong East Asian Mountain Torque) shocking the extra-tropics into a higher AAM/more El Niño-like regime, snow cover advance over Asia supporting continued descending Siberian highs/mountain torques through the fall, and strong sub-surface warming in the central Pacific recently, it looks good at this point for a blocky winter IMO. 

[frd]

Snow cover continues to expand, looking really good so far .

  

[frd]

Eye opener from HM 

 

 

[Prestige Worldwide]

the drought continues?

[frd]

Warm up late October then a big change possible in early November .....  eye candy  and speculation of course on the long range models.  

Similar time frame to 1995. Again speculation of course. Will be fun to watch. 

 

[frd]

 

 

Cool and informative QBO focused post brought over from 33andrain. Snowy knows a lot . Of course, as he mentions, just one part of the puzzle.

.

Snowy Hibbo

• Posted yesterday at 07:11 PM

 

I think I have my QBO analog. All the years that fit my current forecast for +5 to -10 for this season for QBO values at 30mb, minus strong Ninas and Ninos.

 

 

My QBO forecast for the next year is the red line in this image, courtesy of FU Berlin.

 

Key trends to note:

1.  -NAO, deep Greenland high.
2. Massive European trough.
3. Deep troughing around Eastern US.
4. Aleutian ridge.
5. Eastern US pattern driven by NAO.

So not exactly the most sturdy idea, but certainly quite a hopeful pattern.

 

Certainly aligns with the current -AAM situation as well, provided that holds into winter.

 

Of course, just one piece of the puzzle.

[showmethesnow]

8 hours ago, frd said:

 

 

Cool and informative QBO focused post brought over from 33andrain. Snowy knows a lot . Of course, as he mentions, just one part of the puzzle.

.

Snowy Hibbo

• Posted yesterday at 07:11 PM

 

 

Think I would probably fine tune the years he has. At this time I think odds are pretty good we are looking at a warm neutral ENSO. So giving a spread of a cold neutral to a weak Nino that weeds out 5 of those years. 2003 is a moderate Nino. 2000 is a weak Nina that is coming off a strong Nina base state. 1996 is a border line Moderate Nina. 1965 is a weak Nina. 1956 is a border line strong Nina. 

So going with the remaining years gives us this.

 

Not a bad look with plenty of blocking in the NAO domain. Also like seeing the lower heights in the 50/50 region giving us the -NAO/50/50 combo. Hesitate a little when I see the lower height anomalies in the SW but the western based NAO should hopefully help on occasion to keep systems underneath us. Not a particularly cold look and one that will probably mean variable weather for our region as the NAO waxes and wanes. Looking at the individual years the blocking in and around the NAO is a dominate theme. But we are seeing quite a bit of variability in the eastern Pacific (EPO, PNA, Aleutian low). Not really enamored with the general idea of the flow through the states on most members though. With the general look being presented our snow chances will be highly dependent on seeing good blocking in the NAO domain down through central/southern eastern Canada or a -NAO/50/50 combo.

[CAPE]

1 hour ago, showmethesnow said:

Think I would probably fine tune the years he has. At this time I think odds are pretty good we are looking at a warm neutral ENSO. So giving a spread of a cold neutral to a weak Nino that weeds out 5 of those years. 2003 is a moderate Nino. 2000 is a weak Nina that is coming off a strong Nina base state. 1996 is a border line Moderate Nina. 1965 is a weak Nina. 1956 is a border line strong Nina. 

So going with the remaining years gives us this.

 

Not a bad look with plenty of blocking in the NAO domain. Also like seeing the lower heights in the 50/50 region giving us the -NAO/50/50 combo. Hesitate a little when I see the lower height anomalies in the SW but the western based NAO should hopefully help on occasion to keep systems underneath us. Not a particularly cold look and one that will probably mean variable weather for our region as the NAO waxes and wanes. Looking at the individual years the blocking in and around the NAO is a dominate theme. But we are seeing quite a bit of variability in the eastern Pacific (EPO, PNA, Aleutian low). Not really enamored with the general idea of the flow through the states on most members though. With the general look being presented our snow chances will be highly dependent on seeing good blocking in the NAO domain down through central/southern eastern Canada or a -NAO/50/50 combo.

Yeah I am not crazy about that look in general, minus the NA block. Long wave pattern is a bit out of phase for what we want. Not awful, but with the EPAC ridging displaced that far west, there would be a tendency for a trough out west and a SE ridge. We would really need the -NAO to be west based and strong.

[MountainGeek]

Wow -- just checked in to see if the winter discussions are starting, and was pleased to find quite a lot of solid technical discussion and good data points! Here's to hoping we can keep this "quality post" trend going...and looking forward to another fun winter tracking season. 

Pleassseeee just once -- it's time we had a low solar + Modoki + neg NAO + warm blob epic winter. 

On a more serious note, I'm liking what appears to be a more favorable PAC shaping up, since the PAC really hurt us several times last year. 

[frd]

7 hours ago, showmethesnow said:

Think I would probably fine tune the years he has. At this time I think odds are pretty good we are looking at a warm neutral ENSO. So giving a spread of a cold neutral to a weak Nino that weeds out 5 of those years. 2003 is a moderate Nino. 2000 is a weak Nina that is coming off a strong Nina base state. 1996 is a border line Moderate Nina. 1965 is a weak Nina. 1956 is a border line strong Nina. 

So going with the remaining years gives us this.

I can't be sure,  but reading his post, to me at least ,he seems to imply those  years he used are the best QBO matches, not his list for the upcoming winter of his best analog matches .  I believe he puts out a  prelim outlook early Nov. 

[frd]

More on the QBO, this is a great post by Sam ! 

I am starting to feel pretty good about the upcoming winter. 

 

And HM's take on it   .....  

 

 

 

 

[frd]

Damn, the CFS is trip'in

 

 

 

[frd]

 

 

Keep it coming HM.

I have been reading form other sources as well  that so far we are doing very well with NH SCE .  

 

 

[Maestrobjwa]

4 hours ago, frd said:

 

 

Keep it coming HM.

I have been reading form other sources as well  that so far we are doing very well with NH SCE .  

 

 

And as I asked in the Twitter thread...is the snow cover even a legit factor that influences us? Feels like it's been bandied about the last few years...but to little result, lol

[WxUSAF]

Ukie cancels winter

 

[MountainGeek]

3 hours ago, WxUSAF said:

Ukie cancels winter

 

Got any verification scores for handy for that model? 

Also early on last year it seems like almost every model in the LR seemed to be predicting a big -NAO that just kept sliding out into the future and never actually materialized. Maybe we'll play opposite again this year to our advantage. 

[aldie 22]

3 hours ago, WxUSAF said:

Ukie cancels winter

 

I see this as the most likely scenario 

[CAPE]

2 hours ago, MountainGeek said:

Got any verification scores for handy for that model? 

Also early on last year it seems like almost every model in the LR seemed to be predicting a big -NAO that just kept sliding out into the future and never actually materialized. Maybe we'll play opposite again this year to our advantage. 

I would think given the super duper impressive start to the Eurasian snow cover advance, the widespread anomalous warmth the Ukie is advertising must be pretty close to a meteorological impossibility. I can't imagine why Cohen would have even bothered to make that tweet.

[poolz1]

IDK...that UK forecast looks odd. Even the look in the mid lats looks off if you believe its Arctic forecast is correct. General trough signal east of the Rockies with a highly anomalous blue ball over the entire arctic?

[frd]

Good post courtesy 33andrain 

OHweatherMember

• Meteorologist

Posted 8 hours ago

Something like the UKMET isn't far-fetched if the NAO is positive this winter.  It has a ridge over the NE Pacific, and would likely verify colder from the northern Rockies to the Great Lakes than the model implies, but would be up/down over New England, Ohio Valley and the northern Mid-Atlantic (averaging mild as a whole)  and warm over the Southeast.  It's the same pattern we've seen a lot since 2012-13 as discussed on the previous page, but without big blocking to push the cold anomalies farther south.  

 

The NAO forecast this winter is something.  One of the prominent methods will be very wrong.  Analog/statistical methods generally point to a -NAO, while the dynamical models (with the occasional exception of some CFS/CANSIPS runs) point to a positive to strongly positive NAO.  Given the analogs and general blocky nature of the pattern over the last few months, it "feels" like we'll see more blocking this winter than the UKMET has, but I would say confidence is much higher in a -EPO than a -NAO until the NAO goes negative and stays negative.  

[poolz1]

Good post courtesy 33andrain 

OHweatherMember

• Meteorologist

Posted 8 hours ago Something like the UKMET isn't far-fetched if the NAO is positive this winter.  It has a ridge over the NE Pacific, and would likely verify colder from the northern Rockies to the Great Lakes than the model implies, but would be up/down over New England, Ohio Valley and the northern Mid-Atlantic (averaging mild as a whole)  and warm over the Southeast.  It's the same pattern we've seen a lot since 2012-13 as discussed on the previous page, but without big blocking to push the cold anomalies farther south.  
 
The NAO forecast this winter is something.  One of the prominent methods will be very wrong.  Analog/statistical methods generally point to a -NAO, while the dynamical models (with the occasional exception of some CFS/CANSIPS runs) point to a positive to strongly positive NAO.  Given the analogs and general blocky nature of the pattern over the last few months, it "feels" like we'll see more blocking this winter than the UKMET has, but I would say confidence is much higher in a -EPO than a -NAO until the NAO goes negative and stays negative.  

I thought roughly the same thing...but to my eye that ridge seems too far west to produce a mean trough anywhere east of the Mississippi.

I do recall seeing a post on Twitter (can’t remember who posted) but it was an analog for fall/winter with a similar + IOD. Fall = plenty of blocking...winter = zero blocking. So many variables go into analogs than just one signal...but interesting still.

[raindancewx]

I've done data mining on the NAO and the winter tendency will tend to match a year with similar April-May transitions AND similar March-Sept transitions. Years with those tendencies that match 2019 are 1990, 1993, and 2016 among recent years - all positive NAO winters. However, my winter analogs do imply one winter month will see a -NAO, despite the other two months being positive or neutral.

Independently, Apr-May and Mar-Sept are both r-squared around 0.1 for predicting the NAO, but blended together correctly it is stronger than that. On the monthly NAO data, 1975 was a good match to last year for Apr-May, Mar-Sept, and it was a positive NAO winter like last year.

There is also some tendency long-term (r-squared around 0.2) for Box C cold in the Modoki calculation (waters by the Philippines) to be a leading indicator of the NAO.

I've linked to my outlook elsewhere - will be interesting to see how good or terrible it is in a few months.

[CAPE]

WRT the longer range models, we all know the drill in recent winters. Never expect an advertised -NAO to materialize until it does in real time. My hunch is we see much of the same since the last legit, persistent NA blocking period in winter- brief/bootleg ridging in the NAO domain. Not worth worrying over it since it is difficult to predict at range. The more important index to track imo is the AO, as a weakened PV is clearly a key factor for persistent cold air delivery into the midlatitudes, and correlates strongly with above average snowfall for this region. A -AO also increases chances for development of NA blocking.

[frd]

12 hours ago, poolz1 said:

 

I thought roughly the same thing...but to my eye that ridge seems too far west to produce a mean trough anywhere east of the Mississippi.

I do recall seeing a post on Twitter (can’t remember who posted) but it was an analog for fall/winter with a similar + IOD. Fall = plenty of blocking...winter = zero blocking. So many variables go into analogs than just one signal...but interesting still.

 

Read some posts that the oceanic SST models might be coming out with the + NAO winter look due to the highly + IOD.  That may be the factor among all others driving the look you see on the UKmet too.  

However,  as we get deeper into the Fall it should weaken . Certainly it is a huge driver right now without question.

We can get a cold look without the -NAO to help us here in the Mid Atlantic as you know, through a - EPO delivery . Question is what favorable form does the Pac show us in the D J F period. Hard to say right now. And, I assume we get a nice look from the Pac from time to time. 

There was a great post on these very things I wrote about will try to find it and maybe bring it over. 

[frd]

Thought this post by Tip over in the NE forum hit home, talking about the lack of Nino coupling last year, combined with folks using analogs associated with Ninos from way back in the day when those are more likely not going to work in our current warming climate regime. Hey, that was my take.

To me at least this winter we avoid the basin wide bath tub we had in the Pac last year. 

Here is Tip's post:

 

Which again... folks may very well observe ENSO as less coupled to the atmosphere in present eras moving foward because of that, for SD events that fall below a certain magnitude.  I keep pointing this out... but, few seem to acknowledge it before resuming the same mantra and reliance.  But last year ... it took until mid to late February ( as NCEP noted ) for the atmosphere to demonstrate any response/coupling to the state of the NINO fields.  It's one of the reasons so may forecasts busted from the private/novice sector - because those linear reliance' are all f'ed up now; the correlations don't work as well, when they are related to the previous 100 years, when the last 20 years of which are hockey-sticking.    

This isn't just superficially plausible jargon - it's physically sound and being noted by agencies.   But, if we want to just blink twice like robots stuck in 'does not compute' feed-back loop and fall right back into that +5/-5 ENSO stuff... okay.  It's just that after all, this season outlook stuff is speculative - it's nice for the sake of cogency in my mind if folks actually begin to acknowledge this possibility.  Even if we want to say, I am not including for now but it is possible - something. 

I think there is nothing wrong with forecasting SSTs mimicking a weak warm signal, while the atmosphere behaves like a La Nada?   ... I guess we'll let the chips fall where they may... But, that means that other factors ( like the EPO/AO/NAO arc) may be more representative.  It's fascinating stuff - 

 

[frd]

A little more on the warm  blob...... I look at this feature myself with interest,  but its changing now and will do so more in the weeks and months ahead. 

I would never put a lot into this feature as hope to a colder winter in the East, and as many have already commented, iis it  a reaction to a pattern versus a pattern driver. Different views on this one. 

I like this post by Snowy Hibbo from 33andrain 

<<<

I’m not quite so sure I’m really confident in the Pacific regime either.

 

Firstly the “blob” is weakening and is forecast to continue doing so over the winter.

 

Start of August:

 

 

A few days ago: 
 

 

 

The big problem with the present SSTAs is that the warm manifests at it’s strongest around the Aleutians, rather than the Alaskan region focus that we want.

 

The anomalies themselves are weakening quite a bit. And the forecasts I am looking at show some sort of gravitation towards Alaska of the Warm SSTAs, with the Aleutian warm SSTAs subsiding quite a bit. This may make the synoptic pattern better for the Eastern US, but still the positioning of the last month’s worth of blocking is not ideal. 

So it’s improving, but the strength of the anomaly also may decrease in comparison to other winters.

And it also depends on the AAM and associated factors, an Aleutian low may come into play if we see more positive torques and a possible tendency towards a +AAM at some point.

 

>>

[showmethesnow]

Been pretty much MIA the last few weeks due to time constraints and that doesn't look to change much the next month or so. But I thought I would throw out some general thoughts while I am taking some R&R the next few days at camp.

Haven't been particularly enthused with what I have been seeing with the current tendencies nor the longer ranges being displayed on the models. We are once again seeing the dumps into the west setting up the mean troughing in that local just as we have seen the last few years. And as  I have said the last few years without consistant blocking in the nao region and/or down into se Canada we are going to struggle in regards to snow. In conjunction with the west troughing we are also seeing a tendency for strong ridging in the east. Again, not so good. And the nao, is it now doing a disappearing act? I also am not particularly happy with seeing very little to no disruption to the strat PV now nor in the forseeable future (next 15/16 days) allowing for that feature to continue to strengthen. I will say though that there are some indications at 500 mb that this may change come mid November as higher heights build over the pole and we see a displacement of the 500 mb Pv into northern Canada. Now whether this eventually translates upwards into 10 mb region only time will tell (if in fact we do see height builds).

Now as far as the above, we are still early in the game and we are in the seasonal transition period so though I would like to see otherwise, in the long run it probably doesn't mean much. Now if we continue to see these tendencies without a potential disruption/weakening of the Pv come mid November then I will probably start to panic in regards to the first half of winter.

Looking over things for a possible winter forecast on my part in a few weeks and I have more questions then answers at this point. I look in one direction and some notably good winters turn up. And yet when I look in another direction there are some real dogs. So to say there are some conflicting signals in my mind would be an understatement. If I do in fact post a forecast I may actually wait until mid-November. Think at that point some of mixed signals I am seeing now will become much clearer. 

The eastern Pac into the EPO region is beginning to raise questions in my mind. We are not seeing the clarity we once were seeing from the models as they are now getting wishy washy in regards to height builds and strengths within that region. Believe this may be due to the almost pac basin wide warm SST anomalies that the models are picking up on. There is nothing for the models to key on for possible forcings (lack of sst contrasts). One thing I will keep an eye on in the coming weeks will be the central pac. What we have seen in the enso region is a move towards a modoki style sst temp profile with some good neg temp anomalies migrating westward from s America and IOD induced cooling moving eastward from the western Pacific. And in the middle, 3.4 and 4 regions, we are seeing the warm water piling up. Now why this is important is that this will provide the contrast needed to provide the focus for our tropical forcings. In fact I do think we are probably beginning to see the effects of this enso forcing as we are now seeing what looks to be a cold pool beginning to form to the north in the central/western pac. This is what I would expect to see. From what I am seeing I think indications are pretty good that this modoki profile would last at least until the first part of winter.  IF... I am correct on the above (starting to feel somewhat confident) that potentially bodes well for our chances for at least the first half of winter. Never want to second guess the weather, it's going to do what it wants to do after all, but if we see the above occur the natural response of the height builds in the eastern pac should be to shift eastward possibly/hopefully even into the western CONUS. Right now the models have been too far west with that ridging for my tastes which makes us highly dependent on strong blocking over top of us for our chances. But the further and further that ridging gets shifted eastward the less and less we are dependent on blocking. Now if there is any merit to my thoughts we probably won't have to wait long to find out. This should be something the models would begin to pick up on the next week or two.

[Maestrobjwa]

11 minutes ago, showmethesnow said:

One thing I will keep an eye on in the coming weeks will be the central pac. What we have seen in the enso region is a move towards a modoki style sst temp profile with some good neg temp anomalies migrating westward from s America and IOD induced cooling moving eastward from the western Pacific. And in the middle, 3.4 and 4 regions, we are seeing the warm water piling up. Now why this is important is that this will provide the contrast needed to provide the focus for our tropical forcings. In fact I do think we are probably beginning to see the effects of this enso forcing as we are now seeing what looks to be a cold pool beginning to form to the north in the central/western pac. This is what I would expect to see. From what I am seeing I think indications are pretty good that this modoki profile would last at least until the first part of winter.  IF... I am correct on the above (starting to feel somewhat confident) that potentially bodes well for our chances for at least the first half of winter

HM also seems to think the Modoki could be real this time:

http://Anthony Masiello (@antmasiello) Tweeted: modoki https://t.co/9WcA03uHhe https://twitter.com/antmasiello/status/1181381284276441097?s=17