January 2016 Pattern Disco

[CoastalWx]

It does seem like the PV elongates into NAMR. Maybe this helps promote colder air like last year. This latest -AO definitely was gut punching the PV. It's just looks to consolidate later. We shall see if GOAK trough can perhaps send another flux poleward and upward.

[Ginx snewx]

The Canadian and EPS are pretty much the same LR, the GEFS concentrates lower 5H heights way in the SW while the Canadian and EPS the SE, Both the the GEPS and Euro have a much deeper inter mountain high promoting higher heights out west and lower heights out east. I can't post the EPS but it is similar to GEPS  but  lower in heights in the west. Not a torch pattern on any LR model though, actually very conducive to stormy times . 

[RUNNAWAYICEBERG]

The stratosphere so far has been well modeled. It's locked and loaded near the poles. The temporary -AO has been a tropospheric response that no long range model can predict. Such is the nature of chaos in the atmosphere. Still looks like no SSW until at least Feb and I have doubts on that. In the meantime, I have been focused on the Pacific and have mentioned that all along. That's what we should be focusing on. That seems to be a much better predictor for us this season.

You think the -nao on the ens is temporary then?

[ORH_wxman]

GEFS reconsolidate the PV faster near Baffin Island vs the Euro and GGEM ens being still a bit more contorted.

[Baroclinic Zone]

You think the -nao on the ens is temporary then?

 

Too soon to say imo.  Pretty wild spread as we hit mid-month.

 

[RUNNAWAYICEBERG]

Too soon to say imo. Pretty wild spread as we hit mid-month.

nao.sprd2.gif

Thanks. I guess let's get there first before we concern about it breaking down.

[ORH_wxman]

Too soon to say imo.  Pretty wild spread as we hit mid-month.

 

nao.sprd2.gif

 

That's also based on the GEFS too which want to break down the NAO faster than other guidance. It's definitely unclear to me how the Atlantic looks in about 2 weeks.

[Baroclinic Zone]

That's also based on the GEFS too which want to break down the NAO faster than other guidance. It's definitely unclear to me how the Atlantic looks in about 2 weeks.

Right, I was just pointing out an easily accessible visual guidance other than a model.  Its why we preach to not latch onto these fantasies at 7-10 days.

[Typhoon Tip]

heh, ...every set up in the atmosphere is temporary - it's just a matter of the length of time. 

 

yeah all along there has been a wave deconstructive interference thing going on.  we've hit on it several times; until some harmonic wave interaction happens...get used to it. 

 

once in while ... much to our chagrin, a massive teleconnector flip can do this and fail to produce.  if you were to set someone down three weeks ago, who possesses an inkling of clue in these matters, and told them that a 4 standard deviation change from negative pna to positive pna, whilst a strong mjo wave will propagate headlong from phase 6 into 7-8 waves spaces (and oh ...by the way, the ao will tank due to huge freak show waa event at high latitudes) they probably would have edged their bets toward Armageddon. 

 

here though, "phasing" its self ...almost like emergent factor ... can not seem get going.  streams in contention at all scales results.  synoptic ridges fold over too quickly....troughs minor each other out.  It's a big row.  i can't frankly believe any solution in any guidance type out side of 4 days right now.  it's a particularly egregious performance era for the models.  they may not do so badly with the 100,000 ft view, but ... individual events in this make-up are proving too much of a challenge.   oh ...i'm sure now that we've said all this .. the 12z's will wonder on back to 968 mb del marva to gom fuzzy wonder nutters again... 

[RUNNAWAYICEBERG]

heh, ...every set up in the atmosphere is temporary - it's just a matter of the length of time.

True. I should of asked how long can we sustain it instead.

I can pull up the charts too but is it right? I'm not knowledgeable enough to know if it is. So I ask.

[powderfreak]

Lol .2 precip in 10 days on the GFS, thanks Nino

Definitely hasn't been as active or wet as advertised...there have been some long dry stretches so far.

[BuffaloWeather]

If anyone wants to chase an event book your hotel now. 2001, blizzard of 66, 77, and 85 showing up in top analogs. Either the tug or buffalo region. THE PATTERN BECOMES FAR MORE INTERESTING EARLY NEXT WEEK. THE LONG

ADVERTISED PATTERN CHANGE WILL BE TAKING SHAPE ACROSS NORTH

AMERICA...WITH A STRONG WEST COAST RIDGE ALLOWING AN IMPRESSIVE

LONGWAVE TROUGH TO CARVE OUT ACROSS THE EASTERN HALF OF NORTH

AMERICA. THE MEAN PATTERN FOR ALL OF NEXT WEEK WILL FEATURE A DEEP

TROUGH CENTERED IN THE VICINITY OF HUDSON BAY...WITH NUMEROUS HIGH

AMPLITUDE CLIPPER SHORTWAVES MOVING THROUGH THE LONGWAVE TROUGH.

PAST CLIMATOLOGY RESEARCH AND EXPERIENCE SUGGESTS THIS PATTERN CAN

BE VERY ACTIVE FOR HEAVY LAKE EFFECT SNOW IN OUR REGION...AND THIS

APPEARS TO BE THE CASE WITH THIS PATTERN AS WELL.

DEEP COLD AIR SPREADING ACROSS THE GREAT LAKES WILL ALLOW FOR A

STRONG AND DEEP LAKE RESPONSE AT TIMES...WITH THE NUMEROUS MID LEVEL

WAVES PROVIDING LARGE SCALE ASCENT AND DEEPER MOISTURE. THESE WAVES

WILL ALSO BRING CHANGES TO BOUNDARY LAYER FLOW DIRECTION...

SUGGESTING MIGRATING BANDS OF LAKE EFFECT SNOW. OBVIOUSLY AT THIS

TIME RANGE THE DETAILS ARE VERY UNCERTAIN...BUT THE LARGE SCALE

PATTERN CERTAINLY SUGGESTS THE POTENTIAL FOR LONG LASTING...

SIGNIFICANT...HIGH IMPACT LAKE EFFECT SNOW EAST OF LAKES ERIE AND

ONTARIO THROUGH MUCH OF NEXT WEEK. STAY TUNED.

[Ginx snewx]

If anyone wants to chase an event book your hotel now. 2001, blizzard of 66, 77, and 85 showing up in top analogs. Either the tug or buffalo region. THE PATTERN BECOMES FAR MORE INTERESTING EARLY NEXT WEEK. THE LONG

ADVERTISED PATTERN CHANGE WILL BE TAKING SHAPE ACROSS NORTH

AMERICA...WITH A STRONG WEST COAST RIDGE ALLOWING AN IMPRESSIVE

LONGWAVE TROUGH TO CARVE OUT ACROSS THE EASTERN HALF OF NORTH

AMERICA. THE MEAN PATTERN FOR ALL OF NEXT WEEK WILL FEATURE A DEEP

TROUGH CENTERED IN THE VICINITY OF HUDSON BAY...WITH NUMEROUS HIGH

AMPLITUDE CLIPPER SHORTWAVES MOVING THROUGH THE LONGWAVE TROUGH.

PAST CLIMATOLOGY RESEARCH AND EXPERIENCE SUGGESTS THIS PATTERN CAN

BE VERY ACTIVE FOR HEAVY LAKE EFFECT SNOW IN OUR REGION...AND THIS

APPEARS TO BE THE CASE WITH THIS PATTERN AS WELL.

DEEP COLD AIR SPREADING ACROSS THE GREAT LAKES WILL ALLOW FOR A

STRONG AND DEEP LAKE RESPONSE AT TIMES...WITH THE NUMEROUS MID LEVEL

WAVES PROVIDING LARGE SCALE ASCENT AND DEEPER MOISTURE. THESE WAVES

WILL ALSO BRING CHANGES TO BOUNDARY LAYER FLOW DIRECTION...

SUGGESTING MIGRATING BANDS OF LAKE EFFECT SNOW. OBVIOUSLY AT THIS

TIME RANGE THE DETAILS ARE VERY UNCERTAIN...BUT THE LARGE SCALE

PATTERN CERTAINLY SUGGESTS THE POTENTIAL FOR LONG LASTING...

SIGNIFICANT...HIGH IMPACT LAKE EFFECT SNOW EAST OF LAKES ERIE AND

ONTARIO THROUGH MUCH OF NEXT WEEK. STAY TUNED.

Enjoy man, we LES

[JC-CT]

The Canadian and EPS are pretty much the same LR, the GEFS concentrates lower 5H heights way in the SW while the Canadian and EPS the SE, Both the the GEPS and Euro have a much deeper inter mountain high promoting higher heights out west and lower heights out east. I can't post the EPS but it is similar to GEPS  but  lower in heights in the west. Not a torch pattern on any LR model though, actually very conducive to stormy times . 

 

[Ginx snewx]

thats a GEPS GEFS mix, makes sense

[Ginx snewx]

Height Thickness is what I like to look at, anything under 540 this time of year  is good for snow lovers

[Allsnow]

Any truth to the weeklies that week 4 floods Canada with pac air?

[Ginx snewx]

Oh and if anyone wants a good tutorial on thickness, here ya go, love that page by the way

http://weatherfaqs.org.uk/node/152

[JC-CT]

thats a GEPS GEFS mix, makes sense

 

Supposedly the verification scores are meaningfully better than either ensemble product alone - but I haven't seen anyone use them here.

[Ginx snewx]

Supposedly the verification scores are meaningfully better than either ensemble product alone - but I haven't seen anyone use them here.

I use them a lot especially LR, good stuff. I like to look at the individual members . That 17th -18th period has been the opportunity I see

[ORH_wxman]

I use them a lot especially LR, good stuff. I like to look at the individual members . That 17th -18th period has been the opportunity I see

 

 

Jan 16-18 has a decent larger scale setup for snow to the coast...the -NAO is in a good configuration with  a deep trough/low in the 50/50 position...and we have a good ridge out west...so any shortwave in the flow has a lot of ingredients going for it.

 

Still a long ways out obviously...as we know, things can change.

[dryslot]

Time frame around MLK in the past has yielded some decent events in the Northeast

[Baroclinic Zone]

Oh and if anyone wants a good tutorial on thickness, here ya go, love that page by the way

http://weatherfaqs.org.uk/node/152

I like using 540 as my go to # but anything around that usually works in New England.

[CT Valley Snowman]

I think it's pretty clear that the first set of storms Jan 9-12 will not deliver white gold but they could be laying the groundwork for a bigger event. Deep trough in the east with northern stream energy and LES followed by some of coastal storm, perhaps a southern Jet Miller A straight out of the Gulf later in the week. There is still significant potential which is all we can ask for.

[CoastalWx]

You think the -nao on the ens is temporary then?

I think this extend of ridging won't last, but it's possible heights still remain neutral or slightly high as remnant ridging remains up there. El Niño is known to help with a general -AO anyways.

[Zeus]

Oh and if anyone wants a good tutorial on thickness, here ya go, love that page by the way

http://weatherfaqs.org.uk/node/152

 

I gave a tutorial on thickness last night.

 

My audience attempted to give a standing ovation afterwards, but failed.

[Isotherm]

Very provocative read from Cohen in the AER blog today.

 

Ironically, the -AO in place seems to be prohibiting any increase in energy propagation from the troposphere to the stratosphere, effectively ensuring no SSW until at least the end of January.

Energy transfer was sufficient to flip the pattern, but not enough to vanquish the PV, as everyone knows.... since it was was so potent to begin with.

 

Now we are left to ponder whether the colder pattern will remain for most of the balance of the season,  or abate.

Cohen thinks the pattern will hold because it did the past two seasons, and the state of the PV is now similar:

 

As we have been discussing in the blog the stretched and elongated polar vortex predicted for the first half of January is very similar to the configuration of the polar vortex of the past two January’s.  Though in January 2014 no SSW occurred while in January 2015 a significant SSW occurred with record warm temperatures in the polar stratosphere.  Yet both produced repeated Arctic outbreaks across the Eastern United States and overall cold three-month averages from January through March.  Therefore we continue to feel that temperatures will average below normal for much of Southeastern Canada and the Eastern United States for the three-month period January through March.  The models predict that the cold air will be focused in the Plains, surprisingly west for an El Niño winter.  However typically the focus of the cold air slowly shifts eastward as the winter progresses.  Similarly we continue to predict overall below normal temperatures for northern Eurasia.  However the configuration of the polar vortex did not favor cold in Western Europe the past two winters and similarly it does not so far this winter.  But the AO is likely to be more negative this January than the previous two, increasing the chances for Arctic outbreaks into Western Europe eventually.  It continues to be a challenging forecast for this winter and probably nowhere more so than in Western Europe.  Our three-month temperature forecast for January-February-March 2016 is shown at the end of the blog.

 

 

 

 

I disagree with a couple of important points in Dr. Cohen's blog yesterday. First, he noted:

 

"Though in January 2014 no SSW occurred while in January 2015 a significant SSW occurred with record warm temperatures in the polar stratosphere."

 

I would argue that it was a minor SSW. Zonal winds decreased significantly at 60N/10hpa but did not reverse easterly.

 

 

 "The current mature negative AO state predicted by the models in the coming weeks, with strong high pressure centered near the North Pole usually follows a sudden stratospheric warming (SSW).  So the predicted strongly negative AO state is anomalous or unusual because a SSW has not occurred."

 

Research that I've done on prior cases suggests a negative tropospheric AO was present in the vast majority of SSW-precursor patterns. Some cases initiated 1-3 weeks prior, well others, a negative (sometimes strongly negative) AO was in place for 1+ month beforehand.

 

The 1958 case specifically, featured the AO falling to around -3 standard deviations on January 12th, and -4 standard deviations on January 24th. The splitting event at 10hpa then occurred on January 30th, 1958.

 

With respect to the stratospheric pattern going forward: we have a very strong wave-1 pulse in progress which will aid in elongating the vortex. Back on December 11th, I wrote a post with my guess for a potential SSW event around Jan 20th +/- 5 days. Right now, I think January 20th will be too early. But I would still leave the door open in the last week of the month, possibly similar to the 1958 time frame.

 

I'm not sure that most realize how quickly the 10hpa vortex structure can change. The look over the next 10 days is a stable vortex near Greenland - this is correct. However, here's an example.

 

January 22nd, 1958 10hpa - note the potent, slightly elongated but still mostly symmetrical vortex sitting near Greenland:

 

 

 

January 28th, 1958 10hpa - only 6 days later, a splitting event almost complete:

 

 

 

Point being: these events initiate quite rapidly, and a strong vortex structure at D10 over Greenland certainly in no way precludes an event occurring near the end of this month. Will it occur? Maybe not. At the very least, strong pressing against the vortex should continue. And regardless of the whether we see an actual SSW, my winter outlook discussed numerous tropospheric indicators which would support the development of a Jan/Feb -NAO/AO, and that so far appears to be on track. If the stratosphere continues to be perturbed, that would still aid in maintaining the tropospheric higher heights near the pole. Obviously, a split at 10hpa is the ideal, but that doesn't have to occur. Bottom line: I would continue to monitor near the end of the month. And the tropospheric AO currently in place, statistically, does not lessen the probability of a SSW occurring.

 

Current wave-1 pulse:

 

This will aid in maintaining higher heights in NW Canada/polar regions with an elongated vortex.

 

[WinterWolf]

I disagree with a couple of important points in Dr. Cohen's blog yesterday. First, he noted:

 

"Though in January 2014 no SSW occurred while in January 2015 a significant SSW occurred with record warm temperatures in the polar stratosphere."

 

I would argue that it was a minor SSW. Zonal winds decreased significantly at 60N/10hpa but did not reverse easterly.

 

 

 "The current mature negative AO state predicted by the models in the coming weeks, with strong high pressure centered near the North Pole usually follows a sudden stratospheric warming (SSW).  So the predicted strongly negative AO state is anomalous or unusual because a SSW has not occurred."

 

Research that I've done on prior cases suggests a negative tropospheric AO was present in the vast majority of SSW-precursor patterns. Some cases initiated 1-3 weeks prior, well others, a negative (sometimes strongly negative) AO was in place for 1+ month beforehand.

 

The 1958 case specifically, featured the AO falling to around -3 standard deviations on January 12th, and -4 standard deviations on January 24th. The splitting event at 10hpa then occurred on January 30th, 1958.

 

With respect to the stratospheric pattern going forward: we have a very strong wave-1 pulse in progress which will aid in elongating the vortex. Back on December 11th, I wrote a post with my guess for a potential SSW event around Jan 20th +/- 5 days. Right now, I think January 20th will be too early. But I would still leave the door open in the last week of the month, possibly similar to the 1958 time frame.

 

I'm not sure that most realize how quickly the 10hpa vortex structure can change. The look over the next 10 days is a stable vortex near Greenland - this is correct. However, here's an example.

 

January 22nd, 1958 10hpa - note the potent, slightly elongated but still mostly symmetrical vortex sitting near Greenland:

 

 

 

January 28th, 1958 10hpa - only 6 days later, a splitting event almost complete:

 

 

 

Point being: these events initiate quite rapidly, and a strong vortex structure at D10 over Greenland certainly in no way precludes an event occurring near the end of this month. Will it occur? Maybe not. At the very least, strong pressing against the vortex should continue. And regardless of the whether we see an actual SSW, my winter outlook discussed numerous tropospheric indicators which would support the development of a Jan/Feb -NAO/AO, and that so far appears to be on track. If the stratosphere continues to be perturbed, that would still aid in maintaining the tropospheric higher heights near the pole. Obviously, a split at 10hpa is the ideal, but that doesn't have to occur. Bottom line: I would continue to monitor near the end of the month. And the tropospheric AO currently in place, statistically, does not lessen the probability of a SSW occurring.

 

Current wave-1 pulse:

 

This will aid in maintaining higher heights in NW Canada/polar regions with an elongated vortex.

 

Always a great write up Isotherm.  And so easy to understand.  Thank You for posting, and writing in a style that is easy to comprehend, even when discussing a complicated idea such as what you describe above.

[40/70 Benchmark]

Yea Tom, I posted yesterday reminding folks that a SSW, though optimal, is not necessary to achieve a negative AO baseline throughout February of an el nino season.

There are other constructive interferences of such an occurrence.

Potential SSW still very much in the mx late month.

 

Thanks for the enlightenment regarding the precursor considerations....I frankly do not know much about that, so simply deferred to the good doctor.

[CoastalWx]

Good stuff Tom. Cohen seems confusing at times.