Winter 2014-2015 Pattern Discussion Thread I

[Met1985]

Yeah, what more do people want to see for an ensemble mean at 384 hours? Finally seeing what the canadian ensembles sniffed out first. Not bad for an ensemble mean look for the 22nd of Dec.

 

To me this is pretty typical in El Nino patterns were most of the colder air is based right in the SE area were we want it.

[GaWx]

Nearly equal chances a given event will be zr, which makes sense because we are so often on the edge of cold rain. Got any research on what caused those majors? Cad for a lot of the zr? GOM lows for a lot of the sleet/snow? I doubt we've ever had a major from a clipper, and not too many times the deep cold, cold air was in place, thus the zr so many times. I'd love to know how many majors from a split stream. I'd guess a lot. T

Sorry, I missed replying to this. Yep, in ATL, about 45% of majors have been ZR & 55% SN &/or IP. That's why just talking about avg. SN/IP accum.'s of 2" there is far from seeing the whole pic. Notice that 5 of 6 late Dec. majors have been ZR and then ~50% of Jan have been ZR. However, Feb has had 14 SN/IP vs only 5 ZR due IMO to the colder upper levels in relation to the sfc. Cad was there

always w/ZR's though the parent high wasn't nearly always in the classic NE US position. They were most often due to Miller B's or lows that stayed north of the Gulf though I did find 7 of the 31 (including 2/12/2014) to be from Miller A's.

Regarding major SN/IP, I found 31 to be from clearcut Miller A's & A/B hybrid once (IP). The other 7 were from misc. other things like the inland upper low of 3/1/2009, twice from lows that moved N from near FL, one from inland low that moved ESE from S Plains/TX area (that was IP), and thrice from diffuse Gulf moisture setups. I found none from a pure clipper. So, over the last 137+ years, I have found zero major ATL major winter storms from a pure clipper. The closest thing to that would be the ESE moving 3/1/2009 upper low but that still wasn't pure clipper IMO.

[Cold Rain]

Imho- we can get plenty of cold without cross polar flow. -epo's themselves build it up nicely in Canada.

Another promising sign is the gefs members are trending towards a decent -ao. Even a few members with a nice -nao but I'll only believe that once it actually happens. It's been so long that I forgot what one even looks like. Lol

Gefs is doing well with pattern recognition lately. It picked up on the potential change before the euro ens. It shouldn't be discounted at all and is a useful tool.

Totally agree, Bob. Don't need CP flow to get Canada cold. Just pointing out that there is a way down the line for CP flow to set up, for those concerned about no cold air over here. Appreciate your thoughts on the pattern.

[FallsLake]

Totally agree, Bob. Don't need CP flow to get Canada cold. Just pointing out that there is a way down the line for CP flow to set up, for those concerned about no cold air over here. Appreciate your thoughts on the pattern.

Agreed, and the current and future snow coverage is looking good for Canada(where the cold can build):

 

http://www.natice.noaa.gov/pub/ims/ims_v3/ims_gif/DATA/cursnow_usa.gif

http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2014&model_mm=12&model_dd=06&model_init_hh=12&fhour=00&parameter=SNOWIN&level=SURFACE&unit=none&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false

Day16:

http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2014&model_mm=12&model_dd=06&model_init_hh=06&fhour=384&parameter=SNOWIN&level=SURFACE&unit=none&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false

[GaWx]

Totally agree, Bob. Don't need CP flow to get Canada cold. Just pointing out that there is a way down the line for CP flow to set up, for those concerned about no cold air over here. Appreciate your thoughts on the pattern.

CR,

Actually, Canada doesn't have to be cold anomalywise for the SE to get cold. This is common in Nino's and blocking patterns. Remember that even above normal air in Canada woukd be very cold here in many cases if not modified greatly.

[Cold Rain]

CR,

Actually, Canada doesn't have to be cold anomalywise for the SE to get cold. This is common in Nino's and blocking patterns. Remember that even above normal air in Canada woukd be very cold here in many cases.

Yeah, anomaly-wise, true dat.

[Batman]

You're entirely missing the point here, for one, nobody ever (or @ least should have) said it was easy & it's obvious to anyone who has been around meteorology long enough & has fought on the front lines that this is an inexact science, but to merely approach this with a closed mind & reside upon uncertainty (perhaps due to prior negative experiences) alone to attempt discredit their ideas isn't wise. It is bothersome of all bloggers here (some who are very knowledgable in their own right) you are going to attack me for trying & claim I'm somehow "pulling the rabbit out of the hat" when, if anything I have presented extremely lengthy, detailed, educational posts, with extra support w/ references also often made to scientific literature, which certainly dwarfs staring aimlessly into long range model guidance that is a recurring theme throughout a multitude of weather forums.

Webber, thanks for coming to this board and for all of your lengthy, knowledgeable, and informative posts about the LR. I follow this board all of the time, but very rarely post because so many others bring more to the table than I do. Unfortunately some bring little to the table, but insist on being combative with those that do. Too many provide not much more than "this pattern sucks", or "blow torch", or "dumpster fire" and then criticize someone with great skill and more reason behind their opinion than a computer model run. Webber, the evidence you are providing is similar to the evidence nearly every met that makes a winter forecast has been providing for an overall cold winter with above normal precipitation. It amazes me how a week or two  of normal or above normal temps cause folks to abandon what has been thoroughly discussed and forecasted about the winter. It also amazes me how many people put so much value in individual computer runs that have proven time and time again to be unreliable beyond a few days. Please continue to provide us with your knowledgeable and insightful posts. They are much appreciated. 

[FallsLake]

12z GFS dew points at hour 48(can you see the CAD???):

http://www.twisterdata.com/index.php?prog=forecast&model=GFS&grid=3&model_yyyy=2014&model_mm=12&model_dd=06&model_init_hh=12&fhour=48&parameter=DPTF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false

[packbacker]

Yeah, anomaly-wise, true dat.

 

These are 3 of the coldest analogs for us, hopefully we do get something like this, the LR models are getting there.  We want the higher heights in Canada/Greenlad, we need the suppressive blocking.

[Bevo]

Imho- we can get plenty of cold without cross polar flow. -epo's themselves build it up nicely in Canada.

Another promising sign is the gefs members are trending towards a decent -ao. Even a few members with a nice -nao but I'll only believe that once it actually happens. It's been so long that I forgot what one even looks like. Lol

Gefs is doing well with pattern recognition lately. It picked up on the potential change before the euro ens. It shouldn't be discounted at all and is a useful tool.

 

Wasn't it the -epo that really saved us last winter? Most indices were terrible, yet we had pretty decent opportunities.

[Bob Chill]

Wasn't it the -epo that really saved us last winter? Most indices were terrible, yet we had pretty decent opportunities.

Yes, and it was a very unusual pattern. One not seen since 93-94. It wasn't just a -epo, it was a -epo on roids connecting with the pna at times. In the grand scheme, we all got lucky last year south of 40N. There was no sustained blocking and very progressive flow. Overall it was a marginal snow pattern that got maximized with good timing of many events up and down the coast with very anomalous (but short duration) cold shots.

In general, higher heights in the epo region are one piece of the puzzle that helps us with cool temps in the east. But other things have to work in unison. A -epo/-pna pattern sucks for snow more often than not in both our regions.

[GaWx]

Meanwhile, the 12z GFS is fwiw the 4th run in a row with ridging in NW Canada ~12/20. Cold front comes into SE. -AO and neutral NAO. This cooling off then would follow both the Cohen analogs and 1939 fairly nicely. Based on those, this would just be the beginning. Also, until then, model consensus for the SE is far from torchy...it is at best only a little above normal. This fits Niño climo well.

[LithiaWx]

You're entirely missing the point here, for one, nobody ever (or @ least should have) said it was easy & it's obvious to anyone who has been around meteorology long enough & has fought on the front lines that this is an inexact science, but to merely approach this with a closed mind & reside upon uncertainty (perhaps due to prior negative experiences) alone to attempt discredit their ideas isn't wise. It is bothersome of all bloggers here (some who are very knowledgable in their own right) you are going to attack me for trying & claim I'm somehow "pulling the rabbit out of the hat" when, if anything I have presented extremely lengthy, detailed, educational posts, with extra support w/ references also often made to scientific literature, which certainly dwarfs staring aimlessly into long range model guidance that is a recurring theme throughout a multitude of weather forums.

These are all strawman arguments, but thanks for trying. I'm not trying to discredit anyone's ideas, the pulling a rabbit out of a hat remark seems to have ticked you off. No idea why that would do so unless you are overly sensitive about that type of stuff. Possibly due to prior negative experiences?

My point was and continues to be that the GEFS 384 maps that were trotted out yesterday were utter garbage for the U.S. and SE. You had a nice spin of why they weren't but in the end you were relying on a ton of If this happens then this will happen down the line reasoning. That's fine to do but nothing you can bank on anymore than banking on an hour 384 ensemble frame.

[LithiaWx]

Agreed. Maybe instead of staring at a computer model and blindly saying "this sucks" without taking the time to do any research, some people here could learn quite a few things from Eric.

MariettaWX, you are the worse when it comes to being negative and you flip more than the models. Just yesterday you made a post about how you were "on the bandwagon" for cold, then you come on here now attacking credible evidence to justify the cold. Which is it dude?

I haven't flipped. I still think we are headed towards cold by the end of the month. Me and webber see different ways of getting there it seems. He seems to believe a SSW event is a sure bet and I'm not in that camp.

I originally responded to a poster saying the GEFS was a huge improvement yesterday. I pulled up he maps and everything about that map was utter crap for the SEand US. I opined that and then you had someone (webber) tell me why he thought I was wrong. I replied in turn. That's discussion and how discussion works. I hope we get a massive SSW event man, I hope when it happens that the cold du ps right down on the U.S. I'm just not as sure of that event as others. Inreall think its that simple. I truly meant nothin offensive about pulling rabbit out of a hat. I frequently use metaphors and I can see how someone might take it as a swipe but it was honestly me trying to describe something, no offense involved. I am most confused about the notion that I'm somehow trying to discredit the idea of a SSW event. I don't know much about SSW events but like I said before if weather followed a set path based on analogs and past history then long range forecasting would be a breeze. That is why I'm not as sure as webber SEEMS to be.

[GaWx]

Marietta, I honestly don't think the late period GEFS have been bad at all fwiw. They do seem to be signaling a change IMO and they seem to have accelerated it some vs runs of early yesterday and earlier. Regardless, taking 384 GEFS as anything close to gospel is, of course, very risky. I think you're being too tough on Webber as he has laid out his analog based reasons in painstakingly great detail repeatedly, which is not far different from what I have been doing though using different methods. That being said, I agree that a SSW isn't necessary for the strong -AO to get going based on history about which I've posted though I'm not saying they don't help.

*Edited

[LithiaWx]

Marietta, I honestly don't think the late period GEFS have been bad at all fwiw. They do seem to be signaling a change IMO and they seem to have accelerated it some vs runs of early yesterday and earlier. Regardless, taking 384 GEFS as anything close to gospel is, of course, very risky. I think you're being a bit tough on him as he has laid out his analog based reasons for his optimism not far different from what I have been doing though using different methods. That being said, I agree that a SSW isn't necessary for the strong -AO to get going based on history about which I've posted though I'm not saying they don't help.

I'm misunderstood it seems. The written word can do that at times. I'll just take some time away and let everyone else discuss things. I'm obviously not conveying my point in the way I'm intending. I don't mean to be hard on anyone. Webber could be dead on, I have no evidence to refute his claim hat he thinks a SSW event is all but a sure bet. I don't think we have seen enough to claim that at this point, he obviously thinks he has. Have a good afternoon everyone.

[griteater]

Wasn't it the -epo that really saved us last winter? Most indices were terrible, yet we had pretty decent opportunities.

 

The Dec-Mar EPO last winter was actually the second most negative on record back to 1948 (62-63 was first).

[NC_hailstorm]

MJO forecasts aren't great today.

GEFS goes COD before phase 8 now,ECMF goes COD earlier and brings it back out in 4 around the 20th.

 

10mb and 30mb zonal winds are still forecasted to strengthen,meaning a SSW will take a while.

[Webberweather53]

These are all strawman arguments, but thanks for trying. I'm not trying to discredit anyone's ideas, the pulling a rabbit out of a hat remark seems to have ticked you off. No idea why that would do so unless you are overly sensitive about that type of stuff. Possibly due to prior negative experiences?

My point was and continues to be that the GEFS 384 maps that were trotted out yesterday were utter garbage for the U.S. and SE. You had a nice spin of why they weren't but in the end you were relying on a ton of If this happens then this will happen down the line reasoning. That's fine to do but nothing you can bank on anymore than banking on an hour 384 ensemble frame.

 

What straw man argument? My statements are entirely relevant to the conversation at hand & meteorology in general & yes you were trying to discredit my arguments based on the premise of uncertainty alone and I used a little common sense on why this is the case, since I was also at one point several years ago in your current state of my mind. I didn't have just a mere nice spin or am simply banking on the models to produce this solution & clearly mentioned a few days ago why I really like where the models are going in the long range from the standpoint of actually looking into the physical drivers and causes of the pattern shift instead of blankly staring into them & claiming they're utter garbage. I have absolutely no issues with you disagreeing with me, that's perfectly fine, but I would like to see a little more effort on your part than one-two sentence answers, regardless of whether they are right nor wrong, it presents your ideas & concerns with appreciably more credibility. Here's that post once again (minus the pictures of course)...

 

"I wouldn't be the least bit surprised to start seeing hype ramp up some over the coming week or two regarding the potential for a Stratospheric Warming Event in the longer ranges...

 

The GEM & GFS Ensembles as well as the CFSv2 have the classic precursor 500mb set-up to what is observed within 20 days or less in advance of stratospheric warming event. Here's what I mean by this...

 

The next 2 images were derived from pages 3 & 4 in a relatively short, but nice paper co-authored by Garfinkel (which seems to ring a bell) titled "Observed connection between stratospheric sudden warnings and the Madden Julian Oscillation"...

It should take you much less time to read this paper than my enormous post here, lol.

http://www.meteo.psu.edu/~sbf1/papers/Chaim_strat_paper.pdf

 

Amazing how similar the 11-15 day pattern is in much of the guidance to periods just in advance of sudden stratospheric warnings,  especially over the extreme North Pacific including Alaska, eastern Siberia, & the Aleutians...

 

Notice in the lower image + stratospheric temperature anomalies in the "polar cap region" closely follow in the wake of a phase 6-8 MJO pulse while the inverse is true for an upward MJO pulse driving into the eastern hemisphere (phases 1-3) & the interface of the positive & negative height anomalies & stratospheric temperatures in the "SSW precursor region" associated with the MJO is a little ways into phase 6, where the mean center of upward motion shifts well beyond the Maritime Continent & starts to impart vigorous large-scale upper level divergence that causes accelerations, wave packets, & jet streaks within the now more extensive Pacific Jet. The extension of the Pacific Jet coincides with an eastward displacement of its left exit region, where in synoptic scale cyclogenesis is favored w/ increased upper level divergence & poleward evacuation of air in the upper levels.

 

For those who may be struggling to understand how this concept of the eastward progression of the Aleutian Low works as it relates to jet streaks, I made this visual representation w/ demarcations to the regions (Left/Right Entrance/Exit) juxtaposed to a jet streak that will emerge over the next several days in the Pacific, and it assumes that one is upstream/behind (west of) the jet streak looking down towards it... Note when the Pacific Jet is extensive, the Aleutian Low is further east & stronger whereas a retraction of the Pacific Jet leads to a general weakening & northwestward displacement of the Aleutian Low...

 

Going back how this relates to the MJO, an invigorated and amplified Rossby Wave train emanates from the origin of the anomalous convective/signal in upper level winds in west-central Pacific. This Rossby Wave train involves increased amplification of the semi-permanent Aleutian Low feature, ridging in the PNA region in & around western North America & subsequent toughing further east in North America. The weakened pressure /geopotential height (& thus also temperature) gradient downstream of East Asia, (where in the speeds of mid-latitude jet are climatologically the most intense)...

 

Mean 200mb Vector Wind

 

 

..results in a slow down of the polar night jet, due in part to the more robust Aleutian Low, leaving the polar vortex more vulnerable to upwelling intrusions & mixing of the ambient stratospheric air from underneath via synoptic-large scale Rossby/Planetary Waves. Thus, it’s quite common to observe following MJO progression into the Pacific, a net warming to transpire in the polar stratosphere as denoted by this image that lags stratosphere temps w/ phase 7 of the MJO

 

...which if strong enough may lead to displacements & potentially even full-blown obliteration of the polar vortex that can promote crashes in the AO/NAM indices & ultimately favor outbreaks of arctic air into the mid-latitudes. 

 

In layman’s terms, sudden stratospheric warming events have a tendency to follow eastward MJO progression thru phases 6-8, (the late January 2010 sudden stratospheric warming is a classical example of this) which is where we are indeed headed over the next 1-2 weeks in terms of the MJO. I should mention not every Pacific MJO event is followed by a SSWE & it's entirely possible for this one not to result in a SSWE. However, given other parameters at hand & the fact that as HM mentioned on his twitter account the polar vortex will evolve from it's current barotropic mode (i.e. a compact, strong vortex with little notable warming) to a baroclinc regime where large temperature gradients across the polar stratosphere begin to develop. Although large certainties remain in terms of the precise timing & obviously the intensity of such an event, the threat for a SSWE will be generally on the rise as we get deeper into the 2nd half of December."

 

[Ollie Williams]

Webber, thanks for coming to this board and for all of your lengthy, knowledgeable, and informative posts about the LR. I follow this board all of the time, but very rarely post because so many others bring more to the table than I do. Unfortunately some bring little to the table, but insist on being combative with those that do. Too many provide not much more than "this pattern sucks", or "blow torch", or "dumpster fire" and then criticize someone with great skill and more reason behind their opinion than a computer model run. Webber, the evidence you are providing is similar to the evidence nearly every met that makes a winter forecast has been providing for an overall cold winter with above normal precipitation. It amazes me how a week or two  of normal or above normal temps cause folks to abandon what has been thoroughly discussed and forecasted about the winter. It also amazes me how many people put so much value in individual computer runs that have proven time and time again to be unreliable beyond a few days. Please continue to provide us with your knowledgeable and insightful posts. They are much appreciated. 

Agreed.  I've learned more from Webber in a few days than years of posts from the antagonist. Thanks Webber! And please continue to post because you have been a breathe of fresh air in our forum!   

[Webberweather53]

I'm misunderstood it seems. The written word can do that at times. I'll just take some time away and let everyone else discuss things. I'm obviously not conveying my point in the way I'm intending. I don't mean to be hard on anyone. Webber could be dead on, I have no evidence to refute his claim hat he thinks a SSW event is all but a sure bet. I don't think we have seen enough to claim that at this point, he obviously thinks he has. Have a good afternoon everyone.

 

You've essentially taken what I've said and blown it entirely out of proportion, at no point did I say or even imply that "a stratospheric warming event was a sure bet" in fact if you actually read what I posted a few days ago, you'll see I mentioned nothing of the sort & urged caution in a professional manner...

 

"I should mention not every Pacific MJO event is followed by a SSWE & it's entirely possible for this one not to result in a SSWE."

[GaWx]

You've essentially taken what I've said and blown it entirely out of proportion, at no point did I say or even imply that "a stratospheric warming event was a sure bet" in fact if you actually read what I posted a few days ago, you'll see I mentioned nothing of the sort & urged caution in a professional manner...

"I should mention not every Pacific MJO event is followed by a SSWE & it's entirely possible for this one not to result in a SSWE."

Webber,

Keep up the great work! Q: if we don't actually get a SSW, do you still think we'll end up with a strong -AO for much of the Jan-Feb period? Do you think a SSW is crucial or just helpful for this particular winter?

[Webberweather53]

Agreed.  I've learned more from Webber in a few days than years of posts from the antagonist. Thanks Webber! And please continue to post because you have been a breathe of fresh air in our forum!   

 

Webber, thanks for coming to this board and for all of your lengthy, knowledgeable, and informative posts about the LR. I follow this board all of the time, but very rarely post because so many others bring more to the table than I do. Unfortunately some bring little to the table, but insist on being combative with those that do. Too many provide not much more than "this pattern sucks", or "blow torch", or "dumpster fire" and then criticize someone with great skill and more reason behind their opinion than a computer model run. Webber, the evidence you are providing is similar to the evidence nearly every met that makes a winter forecast has been providing for an overall cold winter with above normal precipitation. It amazes me how a week or two  of normal or above normal temps cause folks to abandon what has been thoroughly discussed and forecasted about the winter. It also amazes me how many people put so much value in individual computer runs that have proven time and time again to be unreliable beyond a few days. Please continue to provide us with your knowledgeable and insightful posts. They are much appreciated. 

 

Thanks, I greatly appreciate the feedback... I should be able to have a bit more time to make my posts a bit longer over the coming winter holidays.

[Cold Rain]

Thanks, I greatly appreciate the feedback... I should be able to have a bit more time to make my posts a bit longer over the coming winter holidays.

We're gonna need a bigger boat...um board.

[jburns]

Thanks, I greatly appreciate the feedback... I should be able to have a bit more time to make my posts a bit longer over the coming winter holidays.

Let me use this comment to make a request. It is not necessary for everyone who replies to Webber's posts to quote the whole thing. If I printed out a recent page of this thread, I would have enough sheets to wallpaper my den.

[JoMo]

MJO forecasts aren't great today.

GEFS goes COD before phase 8 now,ECMF goes COD earlier and brings it back out in 4 around the 20th.

 

10mb and 30mb zonal winds are still forecasted to strengthen,meaning a SSW will take a while.

 

Luckily the Bias corrected versions of the MJO forecast keep it mostly in the COD in the longer range.

[franklin NCwx]

Still a good look on the gefs!

[POWERSTROKE]

Whoa, there! They really said that FU could start at the end of the month? I thought we were moving towards a positive pattern change here. Who knew that the weather was getting ready to go all vindictive on us?

Edit: Just slightly ninja-ed by Mack... Argh!!

Lol just saw it.

[packbacker]

SSW getting it act together...drink up SuperJames

 

 

[mackerel_sky]

To my untrained eye, on the maps posted above,if the feature near Alaska would back up slightly, and the block over Greenland would form, the arctic would be unleashed on the central/ eastern half of the US!