On-going analysis/obs regarding the Sudden Stratospheric Warming

[Typhoon Tip]

I am doing this anew, here, because the other January thread appears to have derailed some and I didn't want this lost in the din of that stuff.

What leaps out is that the polar indices that have meaningful statistical correlation on our sensible weather (EPO/NAO/AO) are currently modeled to end the erstwhile cold signal, entering a period when they will register neutral or positive. This, beginning by the end of this month and then out through the first 10-14 days of January.

What is interesting is that whe PNA, which is completing an incredible ~ 30-day time span where it was pegged around -1SD, is currently rising and both the CDC and CPC agencies indicate positive index values through ~ Jan 10th

(I am not too concerned with tropical forcing right now as the MJO has had a tough time this cold season thus far at maintaining any magnitude sufficient to touch off an R-wave response and is currently also modeled to remain weak/ineffectual through the period.)

Here is the AO and NAO:



At first glance this appears to be bad news to winter weather enthusiasm. At closer look, however, there is "spread" among the various members of the GFS ensemble members. By spread (for the less privy reader) we mean that there is disagreement as to what the index will really do. I will add at this point that this dual positive prognostic that we see where both the AO and the NAO are positive in the above image, is actually relatively new. Usually when new signals emerge, they do so in this way, with some members being wildly amplified, and others seeing the new paradigm as a more modest modulation of the pattern. Usually ... a compromised is reached as the signal's residence ages, and what ends up taking place is the mean. Using that as the course of least regret, a medium magnitue positive AO, together with a modestly positive NAO would favor a mild/warm stretch of sensible/synoptics during the first 2 weeks of the month.

However, the PNA justifies a somewhat opposing view point:



Here we see general consensus between CPC and CDC for positive SD PNA period of time that [perhaps] wanes nearing the 10th of January. Looking back along the respective curves ... though it is not always a such a great idea to use that past behavior as a correction moving forward (due to the vagaries of the wind of course ...), most of the positive PNA intervals over the last 45 days have no existed, so it is tough to know if that return to negative has any bases in periodicity, or if it is simply a matter of whatever circumstances that gave rise to the PNA change breaking down. Time will tell. But the "spread" in the CPC version (left) is more pronounced nearing the 10th of January, where the CDC has it's values in decline; the conclusion there is that there is - as usual - increased uncertainty out in time as to what the PNA will really do. Again, the MJO would appear less factorable for the foreseeable future. It has recently emerged as a very weak Wave 3, and modeled to remain weak as it rapidly accelerates through 5. These quadrants are actually opposed to the positive PNA; perhaps the weak presence of the MJO during the time(s) in question is an homage to a disconnect when the MJO is of lesser magnitudes.

The EPO index is interesting; CDC has it modestly negative now, but within about 3 or 4 days it smartly rises the index to as high as +2SD through the 10th of January. Using the D8-10 means of both the GFS and ECMWF operational version, this positive EPO does not appear to be associated with a huge, deep negative GOA vortex, but is edged positive because there is an anomalously large negative geopotential signal over the N Pacific, merely pushing its noise into the EPO domain from the west. The EPO's eastern domain actually appears more negative during the time span. This is like a "west-based positive EPO", where the eastern ~1/3 of the domain space may still offer a NW trajectory into the loading pattern for the Canadian shield. These means below (hopefully) exemplify this paragraph:



Note the modest positive geopotential heights ~55N over western North America, while near neutrality of the EPO's eastern domain, are not really allowing the typical +1 to +2 SD EPO to send the more typical warm signal. In simple terms, this is likely just the +PNA damping the +EPO, but perhaps this all describes why. I find this fascinating, because by a narrow margin, central latitudes of N/A down stream from that Pac/N/A relay may avoid an otherwise very warm signal, when combining a *(+EPO)/+AO/+NAO).

In summary, the use of the teleconnectors out in time obviously have some stochastic recognition (variability and thus should not be taken as absolute!) Barring hugely emerging signals that counter all this, we have some conflicting suggestions: The PNA is sending a cool signal (perhaps stormy as well), while particularly the AO/NAO couplet is opposed. I would have to say, however, we are into the time of the year where other environmental variables become more factorable; such as snow pack over the Canadian shield where said NW trajectories are taking place. AS a winter weather enthusiast, you do not really need to have perfect teleconnectors and then verify perfect observed correlated synoptic layouts to get an appealing solution. So all and all, I would say an active early January is in the cards.

I saved perhaps the best for last! There is what appears to be a SSW just about ready to get underway. This per the CPC's stratospheric analysis and forecast page available to the public here: http://www.cpc.ncep....here/strat_a_f/

It is the graphical depiction of the temperatures in the 1 to 30hPa levels of the stratosphere that are of particular interest. These are the typical levels where SSW's take place; then, subsequently when and if they verify downward propagating (down-welling) behavior, the warm "plumes" will descend through the 50hPa, then 100hPa, ultimately interacting and influencing the depth of the tropopause within the ambient PV. That entire evolution can take as many as 20 days; however, if we look at the historical SSW events and plot them against the AO, we note that the AO falls during warm burst events with some lag applied, ranging from 2 to 3 weeks. The charts below show (using just the 10hPa level for brevity), a clear "sudden" onslaught of warm anomaly originating over N Asia, and eventually encompassing the NP and displacing the cold region away. It is my strong hunch that near the end of 7 to 10 days from now, this will show up here, http://www.cpc.ncep....OND_NH_2012.gif, as a sudden appearance of a warming event at high altitudes when those times arrive.



The progression is left to right, top to down. The intervals are every 48 hours. This is an impressive signal from the American product base, indicating a rapidly growing mass of top-chart warming over an equally large spatial area, eventually over taking the axis of the NP, displacing the previous negative region toward Europe. This perhaps indicating the onset of an SSW over the next week to 10 days, would time an -AO response by perhaps the 20th of January, given to succeeding expectation for downard propagation. During the 7 to 10 days, the 100hPa level does not appear perturbed by these higher altitude changes, however, a the very end of the 50hPa, we do see some intensification of the ambient warm node of Siberian and the NW Territories; that may be propagation ensuing.

Cold during the last 10 days of January.

[CoastalWx]

John, good thoughts. I will also add the Euro ensembles have a big warming too at 50mb over the N pole and down into nrn Canada.

Also, on the FU Berlin site, winds aloft are progged to reverse above 30mb. It also looks like a big wave 1 and even wave 2 response will occur in this area as well. The EP vectors are very strong, but still not pointed poleward. I'm not entirely sure how this whole thing manifests itself so I'm gonna hold off some excitement, but it does look interesting up there. The +QBO is downwelling which also may have a say in all of this too.

I also wanted to reiterate what I said in the other thread. It's good to have the PV (or one of them) on our side north of Hudson Bay. It looks to try and provide confluence to our north, while the other PV pumps up ridging in wrn Canada which like you said..saves us from big warm ups....at least as of now.

[Typhoon Tip]

[Amped]

Nice writup. This might be the biggest warming since 06. Hopefully 10hpa winds will reverse this time.

[Typhoon Tip]

John, good thoughts. I will also add the Euro ensembles have a big warming too at 50mb over the N pole and down into nrn Canada.

Also, on the FU Berlin site, winds aloft are progged to reverse above 30mb. It also looks like a big wave 1 and even wave 2 response will occur in this area as well. The EP vectors are very strong, but still not pointed poleward. I'm not entirely sure how this whole thing manifests itself so I'm gonna hold off some excitement, but it does look interesting up there. The +QBO is downwelling which also may have a say in all of this too.

I also wanted to reiterate what I said in the other thread. It's good to have the PV (or one of them) on our side north of Hudson Bay. It looks to try and provide confluence to our north, while the other PV pumps up ridging in wrn Canada which like you said..saves us from big warm ups....at least as of now.

Scott, it's certainly encouraging for determinism that the Euro cluster is plotting out scenarios that support. It may mean there are large scale influences in the overall circulation system that are more detectable due to their weight.

Also, I am very interested in that wind reversal in the 30mb level - that is a huge correlator with SSWs. Reading that, I tell you what - I am far less concerned about the EP Vectors; though their presentation is obviously important. Having the warming and the wind reversal on top of one another is intriguing.

[Amped]

Also, it appears that Asia has recently fired off some Mountain Torque. The ridge that splits the PV seems to develop rapidly over East Asia. Since the Himalayas are bigger than the Rockies, I imagine they can disrupt the Stratosphere more.

[Great Snow 1717]

The CPC in their latest 8-14 day forecast is predicting mostly seasonable temps and dry/normal conditions across much of the country for the period ending 1/10....and yes I take that with a grain of salt........At this point I'd certainly take seasonably cold along with normal precip......time will tell as always.

I'm wondering if any mets can share his/her thoughts on the lack of clipper systems the last few winters. Seems like clipper systems have gone the way of the hook shot in the NBA!!....

[mahk_webstah]

Seems like we go into a cold dry period up here. Perhaps the mid atlantic gets a storm in the next week or so as everything gets suppressed for us. I guess the question is when will that southwest energy come out and is there any mechanism to bring it north of the mid atlantic? Could we see a clipper or northern stream vort come across and give us some powder? Otherwise perhaps we wait for the Artic air to relax (weekend of Jan 5?) to get another good opportunity?

With a snow pack here and a heavy one to our n and nw, and some artic air around finally I think the risk of warming significantly is unlikely. The risk is dry and cold overwhelming I'd think.

[Amped]

GFS 384 shows our little friend has conquered the arctic circle at 10 hpa. Highest 10hpa heights in the northern hemisphere are @ 90N. 30hpa is also not far from having the highest heights in the hemisphere.

A number of runs in a row have shown this.

[CoastalWx]

So the PV will be near or north of Hudson Bay. While we may see a few day thaw after d10, there are signs ridging in ne Greenland may act to

Push this PV back sw and bring colder air back down. I like seeing this. While the AO might be + it's in a position to try and deliver some colder air....maybe even a little confluence.

[Damage In Tolland]

So the PV will be near or north of Hudson Bay. While we may see a few day thaw after d10, there are signs ridging in ne Greenland may act to

Push this PV back sw and bring colder air back down. I like seeing this. While the AO might be + it's in a position to try and deliver some colder air....maybe even a little confluence.

Euro weeklies offer a mini cool up week 2..but then arctic back down after that

[weatherMA]

Euro weeklies offer a mini cool up week 2..but then arctic back down after that

Cool up

[Mr Torchey]

First guess

bos-1.4

bdl-1.6

pvd-1.9

orh-0.3

[powderfreak]

First guess

bos-1.4

bdl-1.6

pvd-1.9

orh-0.3

Brutal cold by modern standards.

[Typhoon Tip]

Hi folks, just to be cautiously aware - any -AO attributed to the exertion of a SSW on the ambient PV would be closer to the 20th of January and afterward. Please refer to post #3 for demonstrating lag of effect versus propagation. That AO dropped closer to the end of January, 2006, per that example.

As Scott pointed out, it can get cold before then, and despite the +AO/NAO coupled phase states, if nuances in the flow permit. The winter of 1993-1994 is a prime example of how a predominating +NAO is not a 1::1 correlation for positive temperature anomalies. This ensuing 3 to 4 weeks could even borrow from some of that conceptualization should the PNA remain positive most of the time. Just as one scalar version, look at the operational 18z GFS - terrific run for sustaining cold despite a +NAO construct most if not all of the time (just mentioning that run for purposes of the example, only).

I believe the general theme of the first 10 days of January should average below normal due to transient -EPO's having loaded significant cold into the Canadian shield, then the rise in PNA taking place doing the delivery. Given to +PNA, systems can show up in the runs at just about any time, and their amplification longitude should be around 90-80W.

The middle 10 days of January, should the PNA wane toward neutral/negative, prior to SSW attribute -AO, there could very well be a "January thaw" tucked into those 10 days. Usually, when the PNA slips from positive to negative, the EPO should be watched; about half the time, the flow splits as the western N/A ridge retrogrades NW and set up a -EPO. This type of -PNA undercut and can make for wild times - making that mid month period interesting for me.

Should the -EPO take place and the AO dumps week later, that's the coldest heart of winter when that happens.

[Typhoon Tip]

"...The middle 10 days of January, should the PNA wane toward neutral/negative, prior to SSW attribute -AO, there could very well be a "January thaw" tucked into those 10 days..."

Still on track - the first 10 days of January still look seasonally below normal, but unfortunately the smack in the face for winter weather enthusiasts is that the operational models are having difficulty honing in on any events of significance during that period of time - so somewhat cooler than normal, but dry, may be all that is dealt (that is perhaps worse for the Board opining stat - understood). Last weekend many mid-range Global model types were signaling a very cold Wed-Sat for this week; the 00z Euro has backed significantly off that vibe, however, showing more of a kind of seasonal cool stretch. Interesting...

But I am more interested in the mid month period. There is a pretty impressive warm signal apparently well timed with that bold statement above, give or take a day or two on either ends. The MJO has rather suddenly lurched into a cohesive signature at the CPC monitoring, now showing a robust presentation in Phase 4 modeled out in time, that loops in that quatrain, before resuming in a weaker propagation (but probably still effectual), through Phase 5.

That is very bad for winter when the AO and NAO are in hiatus (positive phase states). The positive phase state of these do not have to mean warmer than normal over N/A (particularly in New England), but over the longer haul, ...they do. Compounding that with an MJO that looks like this:

...Eegh. The MJO could signal a warm departure period on its own, but having the AO/NAO (I am not re-posting the current values because they haven't significantly changed since this thread was started; http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml).

Here is a graphical layout for the MJO temperature anomalies/correlation:

Note the significance % on the right hand side. The purple regions are in the 95th percentile, meaning that when there is a warm period in central and eastern areas of the CONUS, there is very high correlation/causality with the Phase of the MJO being in 4, 5, and 6 for that matter.

So in total, what we have here is a double teleconnector signal for warming. This is originating from disparate regions, too, which in the past I have referred to as teleconnector convergence. I haven't done any formal statistical study on that but quite intuitively it is an easy assumption that the concurrent events would lend additional confidence. With that said, ...yeah, I'd say there is above median chance of a mid month good ole fashioned "January Thaw" - whether that turns out to be an all out flame-out, or a modest snow pack obolisher (probably means the latter either way), remains to be seen.

Glimmers of hope: One could almost use these actual caveats...

The first being that the AO has come down just a little in the perceived mean found in that link above. The "spread" among the individual members is still rather high - so there is disagreement as to how positive it will really be. Recent seasonal bias does lend perhaps a little argument that it shouldn't get out of control. This is all less true for the NAO... But, the EPO, interestingly enough, is now progged to go slightly negative around the time the PNA (currently positive) begins to relax.

Putting all that in a blender ... you pour your self a glass of what probably taste more neutral as far as departure expectations, both precip and temp-wise.

Lastly, warm departures in New England can also still mean snow. Does not have to mean rain. It just so happens to be that concurrent with the warm temperature anomalies, the Phase 4 and 5 also favors wetter than normal in the MV-OV-NE regions. If the air mass were only modestly warm biased, and a significant system were to translate through, a wintry result could still transpire - particularly now that we are in the dynamic-savior time of the year. But I am just saying all this to show some commiseration spirit and understanding to those that only care about snow/winter. For me, I'd be just fine with a 3 days of 60+F crocus pusher warmth, just because it's fascinating.

The purpose of this thread not to be forsaken, the CPC monitoring is still initializing a whopper warm lobe in the 10hPa levels of the stratosphere over northern Asia. Over the next 10 days that rotates slowly around to our side while weakening, meanwhile, the lower levels of the stratosphere slowly warm during that period of time; this may indicate a down welling anomaly. If so, the end of the month would likely still see an abrupt AO descent.

[CardinalWinds]

The massive depth of your understanding of meteorology is impressive, TT. It forms the basis on which I research the relevant subject matter. As a casual hobbyist, your posts are much appreciated.

[Typhoon Tip]

Right on queue, here she comes.  Still need to assess it's overall magnitude as well as it propagation nature -   

 

[Typhoon Tip]

For those still interested in monitoring the Sudden Stratosphere Warming event, the products are ablaze!  The late detection at CPC indicates - so far - a moderate warm burst clearly continuing to emerge in the 10hPa level (typical onset altitude).

 

This event is also coming along with a wind anomaly, as well as a significant geopotential height anomaly;  I have found that to be consistent with other SSW's of past years, that separates them from warm (or cold) parcel events that did not propagate.  Here is the geopotential height anomaly, Wave 1 and it is really at the very top of the charts!

 

 

Because the wind observations emerging in tandem with the temperature burst are consistent with other events in the past that preceded propagation therein is some confidence that this will in fact slope downward given time; ultimately to interact with the tropopausal heights and effectual in significant blocking and/or suppression S of the westerlies around the ambient PV of the NH.   When?  There is typically a 2 to 3 week lag as outlined originally in this thread.  Then, it was thought that these observation would materialize by the 7th of the month and here we are on the 8th and we seem to be on schedule.  That suggests that between the 20th and 30th of the month forced descent in the AO teleconnector numbers should be underway.  What interesting is that the AO is already falling prior to this sort of 'outsie-in' influence. 

 

 

Important to note - detecting environmental variables that point to -AO (-EPO/-NAO favored) regimes does not guarantee a harsher winter complexion in the dailies.  It simply means that winter performance has a better chance then otherwise, of succeeding.  There are compensating variables that are just as big, such as the current mega MJO tsunami that entering Phase 5 in a powerful status.  The current prog waste not time in progressing the way straight through the 5, and into 6.  I would not get to concerned about that odd curl back into Phase 6 ... avoiding Phase 7 at this time range - like any other forecast, those extended ranges show day to day stochastic behavior.

 

 

 

As far as the rest of the month .. I still see it potentially turning colder beyond the 20th in particular, but not merely for vagarious translating impulses latching air masses over Canada, but directed by pattern forcing.    Some of this may actually take place prior to the SSW enforcing -AO(-EPO/-NAO), too.  The MJO prognosis from CPC above showed yesterday, the wave terminus was in Phase 7.  There is some question as to the accuracy of the Phase 6 curl because of these daily variations in the mean(outlook), naturally, but the aggression overall timing-wise in moving the wave smartly along, such that it is deep in Phase 6 in just 7 days, could be telling.

 

The reason the MJO is important (imo) is because right now, the wave is antithetic to the cold "vibe" given by the AO (notwithstanding the -EPO immediately ensuing according to the CDC) being that is matured smartly in Phase 4 before propagation E began (just over the last day or two...). However, in not lingering in those Phase spaces and "perhaps" wending to 6/7 cusp sooner rather than later, that becomes a colder MJO teleconnection for middle latitudes of N/A.   Given success to that we would then have 0 warm indicators at those times, and ...pretty much all of the indicators flagging cold.  That much teleconnector convergence would like have hell to pay (and I don't mean of the fiery kind).     Again, it is interesting that all this could happen actually before the SSW hand-shakes with the tropopause.  

[Typhoon Tip]

Emerging warm burst continues to gather strength as it now is above median intensity -

 

[Bostonseminole]

I am doing this anew, here, because the other January thread appears to have derailed some and I didn't want this lost in the din of that stuff.

What leaps out is that the polar indices that have meaningful statistical correlation on our sensible weather (EPO/NAO/AO) are currently modeled to end the erstwhile cold signal, entering a period when they will register neutral or positive. This, beginning by the end of this month and then out through the first 10-14 days of January.

What is interesting is that whe PNA, which is completing an incredible ~ 30-day time span where it was pegged around -1SD, is currently rising and both the CDC and CPC agencies indicate positive index values through ~ Jan 10th

(I am not too concerned with tropical forcing right now as the MJO has had a tough time this cold season thus far at maintaining any magnitude sufficient to touch off an R-wave response and is currently also modeled to remain weak/ineffectual through the period.)

Here is the AO and NAO:

AA1.jpg

At first glance this appears to be bad news to winter weather enthusiasm. At closer look, however, there is "spread" among the various members of the GFS ensemble members. By spread (for the less privy reader) we mean that there is disagreement as to what the index will really do. I will add at this point that this dual positive prognostic that we see where both the AO and the NAO are positive in the above image, is actually relatively new. Usually when new signals emerge, they do so in this way, with some members being wildly amplified, and others seeing the new paradigm as a more modest modulation of the pattern. Usually ... a compromised is reached as the signal's residence ages, and what ends up taking place is the mean. Using that as the course of least regret, a medium magnitue positive AO, together with a modestly positive NAO would favor a mild/warm stretch of sensible/synoptics during the first 2 weeks of the month.

However, the PNA justifies a somewhat opposing view point:

AA2.jpg

Here we see general consensus between CPC and CDC for positive SD PNA period of time that [perhaps] wanes nearing the 10th of January. Looking back along the respective curves ... though it is not always a such a great idea to use that past behavior as a correction moving forward (due to the vagaries of the wind of course ...), most of the positive PNA intervals over the last 45 days have no existed, so it is tough to know if that return to negative has any bases in periodicity, or if it is simply a matter of whatever circumstances that gave rise to the PNA change breaking down. Time will tell. But the "spread" in the CPC version (left) is more pronounced nearing the 10th of January, where the CDC has it's values in decline; the conclusion there is that there is - as usual - increased uncertainty out in time as to what the PNA will really do. Again, the MJO would appear less factorable for the foreseeable future. It has recently emerged as a very weak Wave 3, and modeled to remain weak as it rapidly accelerates through 5. These quadrants are actually opposed to the positive PNA; perhaps the weak presence of the MJO during the time(s) in question is an homage to a disconnect when the MJO is of lesser magnitudes.

The EPO index is interesting; CDC has it modestly negative now, but within about 3 or 4 days it smartly rises the index to as high as +2SD through the 10th of January. Using the D8-10 means of both the GFS and ECMWF operational version, this positive EPO does not appear to be associated with a huge, deep negative GOA vortex, but is edged positive because there is an anomalously large negative geopotential signal over the N Pacific, merely pushing its noise into the EPO domain from the west. The EPO's eastern domain actually appears more negative during the time span. This is like a "west-based positive EPO", where the eastern ~1/3 of the domain space may still offer a NW trajectory into the loading pattern for the Canadian shield. These means below (hopefully) exemplify this paragraph:

AA3.jpg

Note the modest positive geopotential heights ~55N over western North America, while near neutrality of the EPO's eastern domain, are not really allowing the typical +1 to +2 SD EPO to send the more typical warm signal. In simple terms, this is likely just the +PNA damping the +EPO, but perhaps this all describes why. I find this fascinating, because by a narrow margin, central latitudes of N/A down stream from that Pac/N/A relay may avoid an otherwise very warm signal, when combining a *(+EPO)/+AO/+NAO).

In summary, the use of the teleconnectors out in time obviously have some stochastic recognition (variability and thus should not be taken as absolute!) Barring hugely emerging signals that counter all this, we have some conflicting suggestions: The PNA is sending a cool signal (perhaps stormy as well), while particularly the AO/NAO couplet is opposed. I would have to say, however, we are into the time of the year where other environmental variables become more factorable; such as snow pack over the Canadian shield where said NW trajectories are taking place. AS a winter weather enthusiast, you do not really need to have perfect teleconnectors and then verify perfect observed correlated synoptic layouts to get an appealing solution. So all and all, I would say an active early January is in the cards.

I saved perhaps the best for last! There is what appears to be a SSW just about ready to get underway. This per the CPC's stratospheric analysis and forecast page available to the public here: http://www.cpc.ncep....here/strat_a_f/

It is the graphical depiction of the temperatures in the 1 to 30hPa levels of the stratosphere that are of particular interest. These are the typical levels where SSW's take place; then, subsequently when and if they verify downward propagating (down-welling) behavior, the warm "plumes" will descend through the 50hPa, then 100hPa, ultimately interacting and influencing the depth of the tropopause within the ambient PV. That entire evolution can take as many as 20 days; however, if we look at the historical SSW events and plot them against the AO, we note that the AO falls during warm burst events with some lag applied, ranging from 2 to 3 weeks. The charts below show (using just the 10hPa level for brevity), a clear "sudden" onslaught of warm anomaly originating over N Asia, and eventually encompassing the NP and displacing the cold region away. It is my strong hunch that near the end of 7 to 10 days from now, this will show up here, http://www.cpc.ncep....OND_NH_2012.gif, as a sudden appearance of a warming event at high altitudes when those times arrive.

AA4.jpg

The progression is left to right, top to down. The intervals are every 48 hours. This is an impressive signal from the American product base, indicating a rapidly growing mass of top-chart warming over an equally large spatial area, eventually over taking the axis of the NP, displacing the previous negative region toward Europe. This perhaps indicating the onset of an SSW over the next week to 10 days, would time an -AO response by perhaps the 20th of January, given to succeeding expectation for downard propagation. During the 7 to 10 days, the 100hPa level does not appear perturbed by these higher altitude changes, however, a the very end of the 50hPa, we do see some intensification of the ambient warm node of Siberian and the NW Territories; that may be propagation ensuing.

Cold during the last 10 days of January.

 

looks like this will play out well.

[Typhoon Tip]

Increasing evidence that the recent SSW is propagating downward - looks to breach the 100hPa level over the next 7 to 10 days.  

 

 

The current AO prog at CPC is for it to rise abruptly ...soaring past +1SD by Day 10.   That may or may not take place with relative success, but the effect of the warm intrusion into the polarward tropopause may not yet be directing the AO prognostic - a negative AO tail end of January into February would be favored.