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Some Thoughts on the Winter 2021-22 Outlook


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9 hours ago, Roger Smith said:

I posted earlier that I was expecting a reasonably active winter pattern to develop for the central and eastern US, probably a lot of variability but some hope for wintry scenarios at times. 

Now I'm noticing a distinct resemblance to late autumn of 1981 with these very severe rainstorms we are getting here (in BC) -- Nov 1981 had similar episodes. The late autumn of 2006 was very stormy also but not this wet. So if that gives a nod to 1981-82 as one possible analogue then of course it was in that second tier of good winters below the really outstanding ones; not much happened (in the east) during December as I recall since I was living there in 1981, and there was a large-scale pattern change in the new year, severe cold at times, and one or two coastal storms about which I remember very little, the snow largely missed Ontario where I was situated and while it was very cold at times, the ground was almost bare outside the snow belt. Feb 1982 was dry and cold inland too. There was a resumption of severe winter weather in April for about a week. 

About the severe rainfall event, it has washed out two or three major highways and caused urban mudslides. In Nov 1981 there was a bad situation north of Vancouver on the highway to Whistler where a mountain creek swept away a bridge and several vehicles, since then they redesigned all the bridges so that debris can't block the creeks as happened then. A similar disaster in Oct 2003 a bit further north but that was a heavy rain from a Pacific typhoon remnant and I don't remember the rest of the autumn being very stormy. There is some very mild air getting in from the Pacific now and up to quite a high elevation melting a snowpack that just formed, so the flooding with the 6-8" rainfalls is intensified. Luckily there was a fairly good forecast of this and the highways people closed one highway just before it got over-run by a huge flood -- this is ongoing and it may end up totally obliterating the highway for about a half mile, as a river is now running down one side of the divided highway and the barrier is collecting all the debris as it washes over top of the median. 

Haven't seen a start of a winter season much like this in the 27 years I have lived out west, so the pattern is a bit extreme at the moment. 

 

Where were you living exactly?

December 1981 is the 5th snowiest on record dating back to 1956 for my area north of Boston.

Logan airport had very healthy snows...17.6" for the month with about a 1' on 12/6. 

It does look as though there was a rather steep gradient, as Central Park had a meager 2.1". This is also consistent with my expectation...not necessarily that extreme of a gradient, though. Dec 1981 reminds me of Dec 2007 with that sharp cutoff.

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I live near the US-Canada border in south central BC about 150 miles north of Spokane and 50 miles west of the northwest tip of Idaho. We are at about 4000' elevation on the west side of the Columbia River in a ski resort town (Rossland BC). It is also 25 miles due south of YCG in terms of weather stations (and quite a bit higher, we have mountains to our northwest reaching 8000' in the south Monashee range which is just big hills compared to either the Cascades further west or the Selkirks and Rockies further east. Those all go well above 12,000' in places. 

This is a heavy snowfall zone most winters and we can have 3 to 6 feet of snow on the ground at times in Dec and Jan. But spring comes fairly early despite all that. And we hit 112 F here in the heat dome last June.

Have lived in BC since 1995, mostly down at the coast in Vancouver area. Before that, lived in Ontario in various locations, most recently near Peterborough northeast of Toronto. So as an older person I have memories going back about as far as 1960 for Ontario winters. 

Despite all the talk about warming, some of those winters were quite tame as well. Others not so much. :)

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February 1982 is actually fairly similar to last year for US temperatures, spatially. Would be interesting to see that again. I had a cold February, but not in quite the same layout as last year.

I'd have to double check, but I suspect this is the coldest period of 1981-82 nationally:

Screenshot-2021-11-15-6-30-14-PM

The deep purples are -7F or colder for a full month.

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11 hours ago, OHweather said:

1981-82 is an interesting analog. The December pattern featured a huge -NAO but with a -PNA. I'm sure plenty of winter weather fans across the country would take it. 

the April blizzard salvaged that winter in NYC...the Poconos had snow cover from mid Dec to mis March...then 13.5" on April 6th...another 2" a few days later...

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Just some very quick random thoughts...I don't have time in the near-term to do a more final write-up with monthly maps (I had a nice breakthrough covid case that knocked me on my backside pretty good for a week and am a little behind on getting ready for my upcoming move), and I don't have a great feel on how things are going / will go anyways. Despite different tropical forcing than fall of 2011, that season sticks out as one of the decent ENSO/QBO matches that was stuck with a ++EPO for much of the winter (as my write-up detailed, most decent ENSO and QBO matches don't have a large +EPO). My initial thought was we weren't going the way of 11-12, and we still very well may not be, but the EPO continually busting more positive than the longer range ensembles have shown doesn't inspire confidence. 

I feel like our best (hopefully not only, but I'm not sure) chance to disrupt this will be into mid-December. There is increasing agreement on a fairly decent positive east Asian mountain torque late November into early December, along with a notable MJO propagation into early December. While this may initially lead to a Pacific jet extension that helps contribute to a mild spell around the beginning of December (that I think is now hard to avoid) as the jet retracts it could give room for heights to rise into Alaska. Plus, the MJO propagation normally would contribute to blocking development (a strong phase 7 this time of year is nice if we actually get it). And, the pattern on the ensembles around the beginning of December is closer to a pattern that can disrupt the stratospheric polar vortex...not sure if we get a SSW (would think probably not), but as long as it's not strong and coupled to the troposphere we have a chance at a colder / blockier pattern. If the MJO and +EAMT bring a chain of events that leads to more blocking, I think it could turn our fortunes for mid-late December and that could at least carry into the start of January. But if it doesn't (or if it's just a brief blip and we quickly go back to a ++EPO) we'd be in bad shape for the winter as a whole. 

At this point I'd just wait and see, it's still early in the season for sustained cold / snow despite many people wanting it. 

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19 minutes ago, OHweather said:

Just some very quick random thoughts...I don't have time in the near-term to do a more final write-up with monthly maps (I had a nice breakthrough covid case that knocked me on my backside pretty good for a week and am a little behind on getting ready for my upcoming move), and I don't have a great feel on how things are going / will go anyways. Despite different tropical forcing than fall of 2011, that season sticks out as one of the decent ENSO/QBO matches that was stuck with a ++EPO for much of the winter (as my write-up detailed, most decent ENSO and QBO matches don't have a large +EPO). My initial thought was we weren't going the way of 11-12, and we still very well may not be, but the EPO continually busting more positive than the longer range ensembles have shown doesn't inspire confidence. 

I feel like our best (hopefully not only, but I'm not sure) chance to disrupt this will be into mid-December. There is increasing agreement on a fairly decent positive east Asian mountain torque late November into early December, along with a notable MJO propagation into early December. While this may initially lead to a Pacific jet extension that helps contribute to a mild spell around the beginning of December (that I think is now hard to avoid) as the jet retracts it could give room for heights to rise into Alaska. Plus, the MJO propagation normally would contribute to blocking development (a strong phase 7 this time of year is nice if we actually get it). And, the pattern on the ensembles around the beginning of December is closer to a pattern that can disrupt the stratospheric polar vortex...not sure if we get a SSW (would think probably not), but as long as it's not strong and coupled to the troposphere we have a chance at a colder / blockier pattern. If the MJO and +EAMT bring a chain of events that leads to more blocking, I think it could turn our fortunes for mid-late December and that could at least carry into the start of January. But if it doesn't (or if it's just a brief blip and we quickly go back to a ++EPO) we'd be in bad shape for the winter as a whole. 

At this point I'd just wait and see, it's still early in the season for sustained cold / snow despite many people wanting it. 

Jim, Hope you're feeling better. Do you have any thoughts on the more east based niña and -qbo? How that may or may not effect things moving forward? I know most niñas are front loaded but probably not this one. Not sure if you agree with that or not

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10 hours ago, Mr. Kevin said:

Jim, Hope you're feeling better. Do you have any thoughts on the more east based niña and -qbo? How that may or may not effect things moving forward? I know most niñas are front loaded but probably not this one. Not sure if you agree with that or not

Most east-based La Ninas with a -QBO don't have a persistent +EPO, though 2011-12 is an example of one that did. Let's see if we get a decent MJO in early December that shakes up the pattern... 

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42 minutes ago, 40/70 Benchmark said:

2011-2012 was NOT east based.

Not sure if you follow Griteater on twitter but what he tweeted yesterday is the most disturbing thing I’ve seen all fall. A severely positive EPO is the kiss of death for winter, even if you pop a -NAO/-AO all that would do is bring down and trap PAC junk air with the EPO floodgates wide open: 

 

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On 11/16/2021 at 10:35 AM, uncle W said:

the April blizzard salvaged that winter in NYC...the Poconos had snow cover from mid Dec to mis March...then 13.5" on April 6th...another 2" a few days later...

ah but we also had the very notable period of winter weather in January 1982 when we had the snowstorm that downed the plane in the Potomac.  Wasn't that three straight days of measurable snow?  We basically had two double digit snowstorms that season, one in January the other in April.  I think we should adjust that total for our new climate, which is more moist, and we would have near normal snowfall totals (maybe even a little above.)  That extra 2" you noted at the end there was a small storm after the April Blizzard which dropped about an inch at JFK

 

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6 hours ago, snowman19 said:

Not sure if you follow Griteater on twitter but what he tweeted yesterday is the most disturbing thing I’ve seen all fall. A severely positive EPO is the kiss of death for winter, even if you pop a -NAO/-AO all that would do is bring down and trap PAC junk air with the EPO floodgates wide open: 

 

Yea, I'm sure that broke your heart.

It seems worse for la nina than it is for el nino.

I did see that and actually quoted and commented on it. What I said was that it is the most disturbing piece of data yet fans of winter on the east coast, and is a viable concern. 2005-2006 is one of my main analogs, and I have 2011-2011 as a strong extratropical Pacific analog. That said, I am not yet imminently concerned. If December is awful even in New England, then sound the alarms.

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9 hours ago, snowman19 said:

Not sure if you follow Griteater on twitter but what he tweeted yesterday is the most disturbing thing I’ve seen all fall. A severely positive EPO is the kiss of death for winter, even if you pop a -NAO/-AO all that would do is bring down and trap PAC junk air with the EPO floodgates wide open: 

 

.....people are whistling past the graveyard so to speak...

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4 hours ago, 40/70 Benchmark said:

Yea, I'm sure that broke your heart.

It seems worse for la nina than it is for el nino.

I did see that and actually quoted and commented on it. What I said was that it is the most disturbing piece of data yet fans of winter on the east coast, and is a viable concern. 2005-2006 is one of my main analogs, and I have 2011-2011 as a strong extratropical Pacific analog. That said, I am not yet imminently concerned. If December is awful even in New England, then sound the alarms.

He's going to say snowless torchy winter ever year. It's like JB saying cold, snowy winter every season. 

Eventually they'll end up correct though JB less so given today's climate.

I suppose this year has more potential to go wrong than other years. A warm 11/12 style winter wouldn't surprise me given how much negatives there are to overcome.

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2 minutes ago, SnoSki14 said:

He's going to say snowless torchy winter ever year. It's like JB saying cold, snowy winter every season. 

Eventually they'll end up correct though JB less so given today's climate.

below normal snowfall is different than a snowless winter. I consider a snowless winter to be  25% percent or less  of normal snowfall.  

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1 minute ago, 40/70 Benchmark said:

Who?? There is plenty of concern over that.

Uhmm numerous people are ignoring/'downplaying  what has been happening for months.....Some have convinced themselves that every winter is going to be cold and snowy...... 

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1 hour ago, Great Snow 1717 said:

Uhmm numerous people are ignoring/'downplaying  what has been happening for months.....Some have convinced themselves that every winter is going to be cold and snowy...... 

I do not get that sense at all. Most people are concerned about the stubborn lower heights INVOF AK and are well aware that every winter since 2014-2015 has been warmer than average. Hell, all we hear about is global warming...

I disagree.

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On 11/16/2021 at 10:35 AM, uncle W said:

the April blizzard salvaged that winter in NYC...the Poconos had snow cover from mid Dec to mis March...then 13.5" on April 6th...another 2" a few days later...

Not the biggest snowfall of my experience, more like 20th, but the most powerful blizzard by far.  Also the absolute best positive bust I ever expect to see.  On the evening of 4/6, with snow headlines to the south and an OTS forecast for N. Maine, CAR upgraded its cloudy-cold-windy forecast to add flurries.  By 2 AM we had S+ in Fort Kent, the wind howled for 2 days and our Chevette (little car, but it was black) had just one hand-size bit in view, within a drift.  CAR measured 26.3", at the time its biggest snowfall on record.  (It's now 4th.)  Some "flurries".  1981-82 had 185.8" snow, a January morning with -34° and wind 30-35 with light snow, "All roads north of Houlton are impassible" in late Feb (not true but intended to keep more people from needing rescue) and other goodies.

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14 hours ago, 40/70 Benchmark said:

2011-2012 was NOT east based.

You're correct, brain fart when I was typing a quick post half drunk. Regardless, 11-12 is the scariest among the analogs that are decent-ish ENSO and QBO matches. It is generally an exception to most weak-mod La Ninas and E QBO winters (as you know). My guess is even if the EPO is problematic for a decent chunk of the winter that other domains won't be as awful as 11-12. 

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14 hours ago, snowman19 said:

Not sure if you follow Griteater on twitter but what he tweeted yesterday is the most disturbing thing I’ve seen all fall. A severely positive EPO is the kiss of death for winter, even if you pop a -NAO/-AO all that would do is bring down and trap PAC junk air with the EPO floodgates wide open: 

 

It's certainly not a good trend, but I would point out that it's chilly at the moment in spite of a +EPO, so it can be overcome if other indices are more favorable. It does give us very little wiggle room though, as we'll see when we get a mild spell to start December after the ongoing chilly weather. 

7 hours ago, 40/70 Benchmark said:

Yea, I'm sure that broke your heart.

It seems worse for la nina than it is for el nino.

I did see that and actually quoted and commented on it. What I said was that it is the most disturbing piece of data yet fans of winter on the east coast, and is a viable concern. 2005-2006 is one of my main analogs, and I have 2011-2011 as a strong extratropical Pacific analog. That said, I am not yet imminently concerned. If December is awful even in New England, then sound the alarms.

I'd agree with you that if December is awful we're in big trouble, but we're a lonnnnggg way from December being awful. I'd argue that the larger scale drivers may be the most favorable for cold yet that they've been this fall in early December. 

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24 minutes ago, OHweather said:

It's certainly not a good trend, but I would point out that it's chilly at the moment in spite of a +EPO, so it can be overcome if other indices are more favorable. It does give us very little wiggle room though, as we'll see when we get a mild spell to start December after the ongoing chilly weather. 

I'd agree with you that if December is awful we're in big trouble, but we're a lonnnnggg way from December being awful. I'd argue that the larger scale drivers may be the most favorable for cold yet that they've been this fall in early December. 

Yea, I am still pretty confident that December will not suck...at the very least in New England, anyway.

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I'll be happy if my concern (pessimism) from a few days ago ends up not being warranted. The long range has been tricky this fall...the EPO has tended to bust more positively than modeled, so we've been battling Pacific influence and nothing has locked in, but our cold shots have tended to trend colder as they move up in time on the models. That's happening again with the shot arriving around December 5th (with perhaps a storm in front of it):

EPS:

293268780_Webp.net-gifmaker(42).thumb.gif.55798c808c3486312aea8d342c6be593.gif

GEFS for the same timeframe:

gfs-ens_T2maMean_nhem_fh312_trend.thumb.gif.6dcdf2dbed76fd688532f65cb474d76f.gif

While I still think a spell of milder weather follows this shot, as the EPO remains positive and some of the current blocking in other domains relaxes, I do see some hope for a more significant EPO flip the second half of December, along with perhaps another shot for a -NAO. If things still look good I'll try to whip a post together this weekend. My thought, based on having a legitimate arctic tap of air sitting over Alaska and western Canada that has been resulting in decent, albeit fairly brief cold shots, is that if we do ever flip the EPO more negative for a period of time that we'd freeze our butts off. 

The current pattern could probably work for the Great Lakes and New England to get snow...it's trying a bit now and would do better closer to the heart of winter. But the current pattern would be a struggle for the Ohio Valley and Mid Atlantic even in mid-winter. For those areas to have a more legit shot we do need the +EPO to back off. 

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1 hour ago, OHweather said:

I'll be happy if my concern (pessimism) from a few days ago ends up not being warranted. The long range has been tricky this fall...the EPO has tended to bust more positively than modeled, so we've been battling Pacific influence and nothing has locked in, but our cold shots have tended to trend colder as they move up in time on the models. That's happening again with the shot arriving around December 5th (with perhaps a storm in front of it):

EPS:

293268780_Webp.net-gifmaker(42).thumb.gif.55798c808c3486312aea8d342c6be593.gif

GEFS for the same timeframe:

gfs-ens_T2maMean_nhem_fh312_trend.thumb.gif.6dcdf2dbed76fd688532f65cb474d76f.gif

While I still think a spell of milder weather follows this shot, as the EPO remains positive and some of the current blocking in other domains relaxes, I do see some hope for a more significant EPO flip the second half of December, along with perhaps another shot for a -NAO. If things still look good I'll try to whip a post together this weekend. My thought, based on having a legitimate arctic tap of air sitting over Alaska and western Canada that has been resulting in decent, albeit fairly brief cold shots, is that if we do ever flip the EPO more negative for a period of time that we'd freeze our butts off. 

The current pattern could probably work for the Great Lakes and New England to get snow...it's trying a bit now and would do better closer to the heart of winter. But the current pattern would be a struggle for the Ohio Valley and Mid Atlantic even in mid-winter. For those areas to have a more legit shot we do need the +EPO to back off. 

Would it take the mjo to get into phase 7 or cod for that outcome to occur with -epo? Just curious. I'm no weatherman like yourself that's good with patterns, but I have an inkling that the niña eventually going more east based with -qbo will throw a monkey wrench into alot of different things. 

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Wanted to touch on the current pattern, the longer-range ensembles, and what I’m watching for (both cold and warm) moving through the rest of December…some of this stuff may have implications deeper into winter depending on how it does (or doesn’t) impact the stratospheric PV.

We can quibble about if the current / upcoming pattern over the next couple of weeks is good or bad. With a legitimate cold source to tap over the western hemisphere, with a lobe of the PV near northern Hudson Bay and frigid conditions over AK and western Alaska, any cold shots will continue to have bite to them. The mean trough axis is oriented towards the NE U.S. and that isn’t changing for the next couple of weeks, so despite Pacific influence that’s flooding almost all of the rest of the CONUS, the Upper Midwest, Great Lakes and Northeast will be a relatively cool spot…parts of that region may continue to average out to colder than normal on the mean. It’s certainly eating into the torchy pattern for those regions.

With that said, the EPO remains persistently positive overall, with a -PNA and AO and NAO that are now more positive than they’ve been the last week or two. The teleconnections suck. And no, that ridge extending from the Pacific into the west coast is not a +PNA. You need an Aleutian low for a +PNA, we have an Aleutian ridge in the means coming up. With legit cold over Canada and the trough axis sitting near the Northeast we’ll continue to get cold to bleed into our region. But in terms of snow, this pattern can work from the Upper Midwest and Great Lakes to New England, but it sucks for the Ohio Valley and Mid Atlantic. NYC could get lucky but I wouldn’t roll my dice on it if I had other options. It’s not a warm pattern for the NE, but that’s about the only corner of the CONUS that isn’t going to be mild. It’s not the pattern I anticipated when I went with a colder and somewhat snowy winter for the region, and I doubt anyone else who went against the mild outlook anticipated a persistent strong +EPO either. Maybe we keep getting lucky with the cold source to our north and stave off any sort of prolonged mild spell in the Northeast, but it’s not a great pattern for snow for a lot of areas.

For fun, here are last night’s 10-15 day EPS and GEFS depictions…first with what’s wrong with the pattern marked:

19251390_EPSbad.thumb.png.fed78a142b040dd038b4286b2a2cab80.png

1735069270_GEFSbad.thumb.png.cc996d4a6256fe3e86b8668c51c5ca95.png

The main lobe of the PV being on our side of the world, with the trough axis tilted towards the Northeast is staving off a torch for us, but most of the teleconnections are not what we want for a cold or snowy pattern overall, despite some differences in the two outputs. The +AO, NAO and EPO are favored with a strong lower stratospheric vortex, which is quite likely to remain in place for at least the next 10-15 days, with perhaps some hope for change at the end of the run:

gefs_u100_terciles.thumb.png.7dcb5889c6d577ae7bd8cd26e697479f.png

Now, a look at what may seed some future changes on the ensembles if things break the right way…

EPS.thumb.png.74e6d7abdd5270f3f7e7239ff778a656.png

GEFS.thumb.png.dfb10b2c0fd2513de497cac0f29ebb68.png

The GEFS is a little farther along with these late in the run than the EPS. Both agree on a Scandinavian/Urals ridge, which historically is something that can jab at the stratospheric PV. If we can ever get the Asian lobe of the PV to displace farther south, it would really increase the potential for both jabbing at the PV and also make it easier to flip the EPO. Both models have a strong ridge south of the Aleutians…if the PV dips into eastern Asia, there’d be room for that to surge towards AK. Also, if the Scandinavian ridge persisted it’s something that could eventually retrograde towards Greenland and EVENTUALLY flip the NAO back to negative (probably not until at least mid-December though).

As has been discussed by many in the last week or two, there are still signs on many models of MJO movement during the first half of December…first phase 6, then likely 7 around the second week of the month, and some hints at phase 8 if it’s strong enough to keep chugging through late December:

981305036_BOMMJO.thumb.png.4218be98c6faeaf9adb026488b8de2f8.png

1978823264_ECMGEFSMJO.thumb.png.a7af02d979c6b4e2d0998192365be30d.png

Both of these plots have made some rounds recently…but, in La Ninas, both MJO composites show that phase 6 doesn’t really flip the EPO, but phase 7 may, and phase 8 would up the ante for Atlantic blocking too:

911210833_MJObyENSODJF.thumb.png.9c30fc8ea319ec076fb2f6d1cb8d58b2.png

155558969_P6LaNinaDec.thumb.png.56024b6c65e34fffbca2a392e5ad6369.png

1460098877_P7LaNinaDec.thumb.png.4c9ec7c1aa6f26521335f3c5b18eecc3.png

1788348637_P8LaNinaDec.thumb.png.2fd619006b64e8765c3b18b44c11a052.png

In the face of these, it’s not too alarming that the EPO is staying positive through the first week or so of December with an initial phase 6 MJO. Though, it’s worth noting that the pattern over the NW Pacific is a fair bit different in early December than the phase 6 MJO composites. A possible explanation is the PDO. It’s strongly negative, and a -PDO in winter supports a -PNA and +EPO (and is pretty ugly in the AO and NAO domains too):

926594591_PDOSSTs.thumb.png.c45c1f9c0d9287d52c2fa0353a221654.png

 

1524043414_PDOphases.png.6092caab01be84bf498d59daa62b0631.png

42341338_PDOpattern.png.5aa4d8ebfc8b6ea8a70d7135cafa01ba.png

There are exceptions such as 10-11 (and even 08-09 wasn’t awful with a -PDO and La Nina), but it’s somewhat concerning that the Pacific pattern looks quite a bit like a -PDO pattern, with a strong -PDO in place.

Overall, much of the CONUS will be mild through the first half of December in my opinion, with the relative exception of the Upper Midwest, Great Lakes and Northeast. That said, it’s still not a great pattern for snow south of New England. There are potential “seeds” of more substantial change though, and if things break the right way we could quickly flip to a much colder pattern overall at some point during the second half of the month with potential to carry that into January. However, part of me worries that with a strong -PDO we are kind of stuck with the pattern we’ve been seeing. I’m in a wait and see stage at the moment.

 

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18 hours ago, OHweather said:

Wanted to touch on the current pattern, the longer-range ensembles, and what I’m watching for (both cold and warm) moving through the rest of December…some of this stuff may have implications deeper into winter depending on how it does (or doesn’t) impact the stratospheric PV.

We can quibble about if the current / upcoming pattern over the next couple of weeks is good or bad. With a legitimate cold source to tap over the western hemisphere, with a lobe of the PV near northern Hudson Bay and frigid conditions over AK and western Alaska, any cold shots will continue to have bite to them. The mean trough axis is oriented towards the NE U.S. and that isn’t changing for the next couple of weeks, so despite Pacific influence that’s flooding almost all of the rest of the CONUS, the Upper Midwest, Great Lakes and Northeast will be a relatively cool spot…parts of that region may continue to average out to colder than normal on the mean. It’s certainly eating into the torchy pattern for those regions.

With that said, the EPO remains persistently positive overall, with a -PNA and AO and NAO that are now more positive than they’ve been the last week or two. The teleconnections suck. And no, that ridge extending from the Pacific into the west coast is not a +PNA. You need an Aleutian low for a +PNA, we have an Aleutian ridge in the means coming up. With legit cold over Canada and the trough axis sitting near the Northeast we’ll continue to get cold to bleed into our region. But in terms of snow, this pattern can work from the Upper Midwest and Great Lakes to New England, but it sucks for the Ohio Valley and Mid Atlantic. NYC could get lucky but I wouldn’t roll my dice on it if I had other options. It’s not a warm pattern for the NE, but that’s about the only corner of the CONUS that isn’t going to be mild. It’s not the pattern I anticipated when I went with a colder and somewhat snowy winter for the region, and I doubt anyone else who went against the mild outlook anticipated a persistent strong +EPO either. Maybe we keep getting lucky with the cold source to our north and stave off any sort of prolonged mild spell in the Northeast, but it’s not a great pattern for snow for a lot of areas.

For fun, here are last night’s 10-15 day EPS and GEFS depictions…first with what’s wrong with the pattern marked:

19251390_EPSbad.thumb.png.fed78a142b040dd038b4286b2a2cab80.png

1735069270_GEFSbad.thumb.png.cc996d4a6256fe3e86b8668c51c5ca95.png

The main lobe of the PV being on our side of the world, with the trough axis tilted towards the Northeast is staving off a torch for us, but most of the teleconnections are not what we want for a cold or snowy pattern overall, despite some differences in the two outputs. The +AO, NAO and EPO are favored with a strong lower stratospheric vortex, which is quite likely to remain in place for at least the next 10-15 days, with perhaps some hope for change at the end of the run:

gefs_u100_terciles.thumb.png.7dcb5889c6d577ae7bd8cd26e697479f.png

Now, a look at what may seed some future changes on the ensembles if things break the right way…

EPS.thumb.png.74e6d7abdd5270f3f7e7239ff778a656.png

GEFS.thumb.png.dfb10b2c0fd2513de497cac0f29ebb68.png

The GEFS is a little farther along with these late in the run than the EPS. Both agree on a Scandinavian/Urals ridge, which historically is something that can jab at the stratospheric PV. If we can ever get the Asian lobe of the PV to displace farther south, it would really increase the potential for both jabbing at the PV and also make it easier to flip the EPO. Both models have a strong ridge south of the Aleutians…if the PV dips into eastern Asia, there’d be room for that to surge towards AK. Also, if the Scandinavian ridge persisted it’s something that could eventually retrograde towards Greenland and EVENTUALLY flip the NAO back to negative (probably not until at least mid-December though).

As has been discussed by many in the last week or two, there are still signs on many models of MJO movement during the first half of December…first phase 6, then likely 7 around the second week of the month, and some hints at phase 8 if it’s strong enough to keep chugging through late December:

981305036_BOMMJO.thumb.png.4218be98c6faeaf9adb026488b8de2f8.png

1978823264_ECMGEFSMJO.thumb.png.a7af02d979c6b4e2d0998192365be30d.png

Both of these plots have made some rounds recently…but, in La Ninas, both MJO composites show that phase 6 doesn’t really flip the EPO, but phase 7 may, and phase 8 would up the ante for Atlantic blocking too:

911210833_MJObyENSODJF.thumb.png.9c30fc8ea319ec076fb2f6d1cb8d58b2.png

155558969_P6LaNinaDec.thumb.png.56024b6c65e34fffbca2a392e5ad6369.png

1460098877_P7LaNinaDec.thumb.png.4c9ec7c1aa6f26521335f3c5b18eecc3.png

1788348637_P8LaNinaDec.thumb.png.2fd619006b64e8765c3b18b44c11a052.png

In the face of these, it’s not too alarming that the EPO is staying positive through the first week or so of December with an initial phase 6 MJO. Though, it’s worth noting that the pattern over the NW Pacific is a fair bit different in early December than the phase 6 MJO composites. A possible explanation is the PDO. It’s strongly negative, and a -PDO in winter supports a -PNA and +EPO (and is pretty ugly in the AO and NAO domains too):

926594591_PDOSSTs.thumb.png.c45c1f9c0d9287d52c2fa0353a221654.png

 

1524043414_PDOphases.png.6092caab01be84bf498d59daa62b0631.png

42341338_PDOpattern.png.5aa4d8ebfc8b6ea8a70d7135cafa01ba.png

There are exceptions such as 10-11 (and even 08-09 wasn’t awful with a -PDO and La Nina), but it’s somewhat concerning that the Pacific pattern looks quite a bit like a -PDO pattern, with a strong -PDO in place.

Overall, much of the CONUS will be mild through the first half of December in my opinion, with the relative exception of the Upper Midwest, Great Lakes and Northeast. That said, it’s still not a great pattern for snow south of New England. There are potential “seeds” of more substantial change though, and if things break the right way we could quickly flip to a much colder pattern overall at some point during the second half of the month with potential to carry that into January. However, part of me worries that with a strong -PDO we are kind of stuck with the pattern we’ve been seeing. I’m in a wait and see stage at the moment.

 

I think with -pdo that intense, we would probably need the ao/nao real negative to possibly trump it imo. Do u agree or will more need to happen? Also, I think the niña is more east based with -qbo. Could that help out?

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21 hours ago, Mr. Kevin said:

I think with -pdo that intense, we would probably need the ao/nao real negative to possibly trump it imo. Do u agree or will more need to happen? Also, I think the niña is more east based with -qbo. Could that help out?

East based La Nina with a -QBO "should" help, but so far the pattern isn't reflecting it. Getting a -AO/-NAO or -EPO would push more cold into the CONUS and increase snow potential. That's not imminent though...first window for it appears to be after mid-December. 

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1 hour ago, OHweather said:

East based La Nina with a -QBO "should" help, but so far the pattern isn't reflecting it. Getting a -AO/-NAO or -EPO would push more cold into the CONUS and increase snow potential. That's not imminent though...first window for it appears to be after mid-December. 

I know we got a long ways to go Jim. Trying to be optimistic just like everyone else who likes winter. So far, things are real unfavorable for cold. 

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