December Medium/Long Range Discussion

[BristowWx]

10 minutes ago, showmethesnow said:

Funny you mention that. As I watched the models tank the last few days I decided I might as well take advantage of what favors to be a slow early January time period. Just booked a 10 day trip out to Vegas. And yes, I love to play my slots. Figured if I was going to be frustrated I might as well do it in style and drunk as a skunk. 

 

 

 

 

 

 

 

 

Sounds like an unmitigated disaster of getting punched in the face repeatedly for days on end.  The weather in January I mean..the Vegas trip however sounds awesome!

[CAPE]

27 minutes ago, showmethesnow said:

Funny you mention that. As I watched the models tank the last few days I decided I might as well take advantage of what favors to be a slow early January time period. Just booked a 10 day trip out to Vegas. And yes, I love to play my slots. Figured if I was going to be frustrated I might as well do it in style and drunk as a skunk. 

 

Outside of a fluke, Dec is dead. There are some positive signs in the LR that indicate we may not have to punt the first couple weeks of Jan. I have been keeping any eye on the Pac wave train, particularly the persistent ridge to the N of Hawaii. Seeing some retrograding of that feature back towards the IDL in recent runs, esp on the EPS, allowing some ridging to develop in the W US.

[showmethesnow]

Just now, C.A.P.E. said:

Outside of a fluke, Dec is dead. There are some positive signs in the LR that indicate we my not have to punt the first couple weeks of Jan. I have been keeping any eye on the Pac wave train, particularly the ridge that has been persistent to the N of Hawaii. Seeing some retrograding of that feature back towards the IDL in recent runs, esp on the EPS, allowing some ridging to develop in the W US.

Late December died a painful death in just a matter of a couple of days. Really thought we had a shot there with the initial advertised pattern but then the models had other plans. Turned into a north Stream dominated pattern through the holidays so you can never rule anything out as the models play with the energy diving down but at this point chances look pretty rough.

I thought the EPS has taken a couple of steps in a positive direction as well. Still not really fond of the GEFS, though I can see how that can somewhat quickly morph into a workable pattern. I am really taking what I see in the long range with a huge grain of salt at this time. With what we are seeing in the Strat with the PV it is quite possible playing havoc with the models.

[CAPE]

4 minutes ago, showmethesnow said:

Late December died a painful death in just a matter of a couple of days. Really thought we had a shot there with the initial advertised pattern but then the models had other plans. Turned into a north Stream dominated pattern through the holidays so you can never rule anything out as the models play with the energy diving down but at this point chances look pretty rough.

I thought the EPS has taken a couple of steps in a positive direction as well. Still not really fond of the GEFS, though I can see how that can somewhat quickly morph into a workable pattern. I am really taking what I see in the long range with a huge grain of salt at this time. With what we are seeing in the Strat with the PV it is quite possible playing havoc with the models.

Yeah the strat stuff is a definite wildcard with the guidance going forward, and it looks like the MJO will continue through the bad phases and head towards the COD as it does over the next week or so.

[CAPE]

CoastalWx posted this in the NE subforum. Nice read and "cutely" done.

https://www.climate.gov/news-features/blogs/enso/december-2018-enso-update-relationship-advice

[Wonderdog]

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

CoastalWx posted this in the NE subforum. Nice read and "cutely" done.

https://www.climate.gov/news-features/blogs/enso/december-2018-enso-update-relationship-advice

That was a great write-up. We all need a little humor waiting for the atmosphere to respond.

[AfewUniversesBelowNormal]

That storm in a little while sure is exciting. It won't take much PNA shift for it to take a coastal track. 

[WxUSAF]

Would need to have this propagate down to lower altitudes, but this is a good sign and support for the GFS/GEFS doing this.  Think this is maybe the first time the EPS has split the vortex?

 

[pasnownut]

4 minutes ago, losetoa6 said:

Considering models had yesterday's/ today's storm a 980s bomb cutting way west of us at day 6-8 only to morph into weak 1012 low with coastal redevelopment  it wouldn't surprise me.  No shortage of coastals this season and that's a good thing no doubt . Only a matter of time before one is white .

Very true.  We've seemingly got the STJ working, just need the canooks to get their sh!t together and we'll be doing just fine.  Overnights have taken a slightly more workable look in the way out there range.  Seeing that cold dumping into the west just hurts when we finally have all players showing up.  Just need them to play nice and it could be a really nice time here in the east.  

[osfan24]

This would have been a heck of a winter storm for our area. Swing and miss on two big storms now. Hope we can make up for it during our prime snow season.

[AfewUniversesBelowNormal]

Nice little warm up for Europe. A little change lol. 

[frd]

Better than no consistency at all I guess. 

 

 

 

[Maestrobjwa]

52 minutes ago, frd said:

Better than no consistency at all I guess. 

 

 

 

So what does that mean, exactly?

[EastCoast NPZ]

12 minutes ago, Maestrobjwa said:

So what does that mean, exactly?

It means everybody is strung along for another 2 weeks of SSW hope until we realize it does nothing to help us.

[BristowWx]

4 minutes ago, Maestrobjwa said:

So what does that mean, exactly?

It means we wait for strat warming to save January.  Last line of defense. 

[Maestrobjwa]

Just now, EastCoast NPZ said:

It means everybody is strong along for another 2 weeks of SSW hope until we realize it does nothing to help us.

Okay...so, now somebody give me a non-cynical translation of it...lol

[Bob Chill]

4 minutes ago, Maestrobjwa said:

Okay...so, now somebody give me a non-cynical translation of it...lol

It's complicated but the strat polar vortex has been really strong the last 3 years and has helped reinforce the polar vortex in the troposphere. Main reason we have had a long run of a very postive AO/NAO. 

This year the strat pv has never been strong and is modeled to undergo significant warming/weakening/displacement. This could *potentially* help open the door for blocking in the troposphere to set up as we move forward in time. 

The very tricky part is the strat and trop don't work in unison. Meaning you can still have a +ao/nao with a weak or displaced strat pv. If they couple and work together it can really help blocking. The thing is there's no way to know in advance how the troposphere will respond to a strat warming event. 

The last time we had a weak strat pv and warming event was 2010-11. It helped. 09-10 also had an early warming event and we all know how blocking was that year. Will it work in our favor this year? We won't know until it actually happens. There can be a lag as well meaning a strat warming event takes place but blocking in the troposphere doesnt happen for a month. There's just no way to predict how any of it is going to go down. Just be glad the strat pv is weak and may have a warming event but don't expect instant gratification. 

[Bob Chill]

Some glimmers of hope for the warm pattern not lasting into January. Eps opened up the spread late in the run and backed of a little with ridging in the east and hostile pac. Gefs is doing the same. Still looks hostile but not as dire as it's been. Keep that trend up and pray we move towards at least a seasonable setup before new years. Next 10 days are looking bleak no matter how you slice it. 

[MDstorm]

14 minutes ago, Maestrobjwa said:

Okay...so, now somebody give me a non-cynical translation of it...lol

If we have a wind reversal as depicted, the chance for multiple vacancies in the Panic Room increases as we head into January. 

Bob gave the more technical response. 

[Maestrobjwa]

30 minutes ago, Bob Chill said:

It's complicated but the strat polar vortex has been really strong the last 3 years and has helped reinforce the polar vortex in the troposphere. Main reason we have had a long run of a very postive AO/NAO. 

This year the strat pv has never been strong and is modeled to undergo significant warming/weakening/displacement. This could *potentially* help open the door for blocking in the troposphere to set up as we move forward in time. 

The very tricky part is the strat and trop don't work in unison. Meaning you can still have a +ao/nao with a weak or displaced strat pv. If they couple and work together it can really help blocking. The thing is there's no way to know in advance how the troposphere will respond to a strat warming event. 

The last time we had a weak strat pv and warming event was 2010-11. It helped. 09-10 also had an early warming event and we all know how blocking was that year. Will it work in our favor this year? We won't know until it actually happens. There can be a lag as well meaning a strat warming event takes place but blocking in the troposphere doesnt happen for a month. There's just no way to predict how any of it is going to go down. Just be glad the strat pv is weak and may have a warming event but don't expect instant gratification. 

Not looking for instant gratification, good sir...the core of the worry I often mistakenly express on here is more season-centered, not as much "snow right now!" centered. (I have a tendency to worry about bad stretches being bad indicators...not logical, I know)

Now 2010-11...did this strat warming have anything to do with Commutageddon? Lol

[Zach’s Pop]

 

2 hours ago, Isotherm said:

 

Well, since you inquired, here's what I posted on another board a few days ago. Very little change from previous thinking. Transitional period 21-22nd with neutralizing temperatures, followed by a sufficiently cold pattern to produce winter threats thereafter. There will be a temporary suppression of heights in the W US via the diminutive -MT/FT pulse in the 24th-28th period, but it will be countervailed by higher heights in the NAO domain, yielding a zonal flow (i.e., no significant ridging in the East). Note recent runs continue to correct w/ higher heights in W North American and the NAO domain, and this will continue, as a function of momentum alterations and vertical wave driving/strat changes. By the end of December, changes continue will a more Nino-esque Pacific structure developing.

 

The medium range pattern in late December is multifactorial, and the provenance of the depictions seen on model data are as follows:

 

1. There will be a relatively insignificant extratropical contribution of -MT in about a week, which aids in an ephemeral Pacific jet retraction.

 

2. The intraseasonal/MJO signal currently in phase 3, precluding full-entrance into GWO p5 right now, will be in the decay/coherency loss phase in late December, but will also aid adjunctively in the ephemeral jet retraction ("Nina-esque" interlude)

 

3. However, contemporaneously, the ongoing tropospheric forcing/MT/AAM induced stratospheric displacement event is inducing severe model volatility and rendering NAO/AO domain geopotential height forecasts quite inaccurate. Note the robust blocking signal in the NAO domain on the 23rd/24th (not detected a few days ago), which is rapidly lost by Christmas on the EPS. This is apocryphal in my opinion. The z150 vortex will be pushed into Siberia by the 23rd-24th w/ significant height rises in the southern AO/NAO domains. So, this correction will continue.

 

4. The diminution of the MJO signal as we approach Christmas, and the concurrent reinvigoration of the walker cell induced CPac. forcing, will force the GWO back toward p5 toward very late December. And as the strat. event realizes, all the putative dominios align, with a more classic Nino-esque Pacific structure near the end of month/New Year.

 

What does this mean sensible weather wise? I'm sensing quite a bit of worry regarding late December. There will be a transient momentum loss induced jet retraction which retrogrades the mean trough axis in the CONUS, but, concurrently, the AO/NAO domain geopotential heights will be more positive than currently progged. And therefore, the SE-ridge will not be as robust as some modelling indicates 25-28th. The flow will go more zonal for a period of several days (if you want to call this "gradient", but I dislike the word) as the momentum flux alters. 

 

Nothing else has changed regarding the "transitional period 21st-22nd", with the pattern conducive for a threat thereafter.

 

1 hour ago, Maestrobjwa said:

Okay...so, now somebody give me a non-cynical translation of it...lol

Read Tom’s thread in the general weather section. The guy is BRILLIANT. The reason the models are beginning to look less hostile in the LR is the very reasons he said they would a week ago. If you listen to anyone on the weather boards, Tom is the guy to follow 

[frd]

Well regardless, the seasonals see something positive about Jan with regards to snowfall. 

However, for our region I like the UKmet and Euro better the other two.

The Meteo France upon a closer look, seems below normal to me so, I am not sure how the headline form Ben is actually correct for our region, for Boston yeah looks good. Well in his defense, he did say the NE.  

I do not see any big snows in the South. So, maybe this means maybe a Miller B evolution, not really sure.    

 

 

[frd]

Updated CFSv2 

 

 

[frd]

The GFS is just a bit too fast in the weakening process, otherwise, game still on.   

 

[Bob Chill]

30 minutes ago, Zach’s Pop said:

 

 

Read Tom’s thread in the general weather section. The guy is BRILLIANT. The reason the models are beginning to look less hostile in the LR is the very reasons he said they would a week ago. If you listen to anyone on the weather boards, Tom is the guy to follow 

Agreed. I've had some great discussions with Iso over the years. He brings a comprehensive viewpoint that is unmatched on the board. I (and most regular posters) and very regional focused. Iso brings huge flavor to the big picture. 

When the Pac takes a dump on us it's usually stubborn to relinquish its stranglehold. Holiday week will likely be a transitional week at best and in typical MA fashion we'll have to wait our turn while the NE gets a good event first. Totally fine if that happens again as long as the pattern improves to something serviceable before the year is done. 

[psuhoffman]

The cfs continues to advertise a sudden flip to high lat blocking and eastern trough around Jan 15.  It flipped about a week ago to the euro seasonal camp and has only become more adamant since. I know it's the cfs but it was the last holdout with the euro U.K. and jamstec all advertising a similar longwave pattern.  

I know long range guidance is very erratic and should be taken with skepticism but when all the guidance is in such good agreement AND more importantly fits the analog pattern evolution very well I think there is reason to believe it is likely on the right track.  Additionally the PV continues to be weak. For the next 2 weeks it's mostly configured in ways that aren't good for us but keep that thing weak and beaten around and it can quickly and easily morph into a good pattern if blocking develops. So we wait with high expectations that things improve dramatically soon. 

Until then my expectations are low. There is a very small window right around Xmas behind the big bomb cutter. The following wave could get under us if it times up. But that's something that won't resolve until a few days out at best. 

The look does get ambiguous but still generally hostile towards New Years. I'm not that optimistic until towards the 10th on. Not just because of current guidance. Pretty much all the analogs except 1964 were a barren wasteland for snow the first two weeks on January. The were clippers in early 2003 and 2010 and that was it. 1966, 1969, 1978, 1987 all had no snow until around January 20th. It's amazing how consistent the analogs were and this year is followed the pattern so expectations should be low until mid January to avoid disappointment. That doesn't mean a fluke cannot happen but I'm not holding my breath. 

One note on the pattern after. I am seeing posts lamenting the destruction of cold in our source regions. First of all snowcover up there won't be significantly impacted. The average temps are so cold that even a +10 anomaly won't melt the snowpack in most cases.  It's actually going to be snowy in some places north of us during this period. And once we get to mid January we won't need anomalous cold to get snow. Air that's +5 up in Canada will be fine for our purposes if we get a consistent nw flow. We just need to get the trough out of the PAC NW and get our flow originating from northern Canada and not the Pacific. Many of our snowiest periods weren't our coldest. Usually extreme cold is dry. Blocking patterns typically aren't extreme cold ones but once we get past New Years that's fine, get the storm track suppressed south of us and our flow from the north and roll the dice. 

[pasnownut]

2 minutes ago, Bob Chill said:

Agreed. I've had some great discussions with Iso over the years. He brings a comprehensive viewpoint that is unmatched on the board. I (and most regular posters) and very regional focused. Iso brings huge flavor to the big picture. 

When the Pac takes a dump on us it's usually stubborn to relinquish its stranglehold. Holiday week will likely be a transitional week at best and in typical MA fashion we'll have to wait our turn while the NE gets a good event first. Totally fine if that happens again as long as the pattern improves to something serviceable before the year is done. 

Seeing that ISO is still holding the line, is great and lends credence to our SSW convo that some have been chatting about.  Looking like we should see the effects as we head towards the New Year, and per his read, he things the SE ridge is being overmodeled.  Even if we get zonal pattern, it surely isnt a horrible base state to have something NS drop in to pay a visit.  Thats how i see it anyway.

[psuhoffman]

11 minutes ago, frd said:

Updated CFSv2 

 

 

If we got a repeat of the pattern last march/April but in mid winter we will be in good shape. 

[psuhoffman]

16 minutes ago, frd said:

Well regardless, the seasonals see something positive about Jan with regards to snowfall. 

However, for our region I like the UKmet and Euro better the other two.

The Meteo France upon a closer look, seems below normal to me so, I am not sure how the headline form Ben is actually correct for our region, for Boston yeah looks good. Well in his defense, he did say the NE.  

I do not see any big snows in the South. So, maybe this means maybe a Miller B evolution, not really sure.    

 

 

Since when do we care what the French think anyways...

[pasnownut]

3 minutes ago, psuhoffman said:

The cfs continues to advertise a sudden flip to high lat blocking and eastern trough around Jan 15.  It flipped about a week ago to the euro seasonal camp and has only become more adamant since. I know it's the cfs but it was the last holdout with the euro U.K. and jamstec all advertising a similar longwave pattern.  

I know long range guidance is very erratic and should be taken with skepticism but when all the guidance is in such good agreement AND more importantly fits the analog pattern evolution very well I think there is reason to believe it is likely on the right track.  Additionally the PV continues to be weak. For the next 2 weeks it's mostly configured in ways that aren't good for us but keep that thing weak and beaten around and it can quickly and easily morph into a good pattern if blocking develops. So we wait with high expectations that things improve dramatically soon. 

Until then my expectations are low. There is a very small window right around Xmas behind the big bomb cutter. The following wave could get under us if it times up. But that's something that won't resolve until a few days out at best. 

The look does get ambiguous but still generally hostile towards New Years. I'm not that optimistic until towards the 10th on. Not just because of current guidance. Pretty much all the analogs except 1964 were a barren wasteland for snow the first two weeks on January. The were clippers in early 2003 and 2010 and that was it. 1966, 1969, 1978, 1987 all had no snow until around January 20th. It's amazing how consistent the analogs were and this year is followed the pattern so expectations should be low until mid January to avoid disappointment. That doesn't mean a fluke cannot happen but I'm not holding my breath. 

One note on the pattern after. I am seeing posts lamenting the destruction of cold in our source regions. First of all snowcover up there won't be significantly impacted. The average temps are so cold that even a +10 anomaly won't melt the snowpack in most cases.  It's actually going to be snowy in some places north of us during this period. And once we get to mid January we won't need anomalous cold to get snow. Air that's +5 up in Canada will be fine for our purposes if we get a consistent nw flow. We just need to get the trough out of the PAC NW and get our flow originating from northern Canada and not the Pacific. Many of our snowiest periods weren't our coldest. Usually extreme cold is dry. Blocking patterns typically aren't extreme cold ones but once we get past New Years that's fine, get the storm track suppressed south of us and our flow from the north and roll the dice. 

Thats a great reminder regarding the pos anomalies that we would see north of us. 

Some will think were in trouble but in Jan/Feb its not as big a deal and as you said it will be likely "cold enough" for it to snow.  

While i think your right that it may take from mid Jan onwards, I'd think that by this time next week, we may be seeing 10 day maps that get things looking more interesting.  Its no shutout pattern, so for me, thats a win in and of itself.  Transient is fine.