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Countdown to Winter 2017-2018 Thread

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That ridging near AK and overall higher heights near the N Pole with troughing near Davis Straits is how I envision it. I'm still not sold on true blocking..but I'll take a decent Pacific. Teleconnects to a SE ridge. 

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3 minutes ago, 40/70 Benchmark said:

The mechanics of it is that the low redevelops into a triple point just near the south coast, from the surface up....thus the capacity of the high to negate the WAA from the parent low is attenuated with height...ie the profile is slanted. The surface remains colder, while the warmth overtakes the mid and upper levels, hence the sleet...but once sufficient latitude is achieved, the entire column succumbs to the colder redevelopment.

In some instances, There is really no primary low and its more of a series of weak waves of LP moving along the front with a high to the north to keep the colder air in the mid levels and the surface.

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2 hours ago, ORH_wxman said:

A good high to the north also enhances the frontogenesis...it's what helps a mundane transition event (or mundane overrunning event if you stay all snow) turn into a big front end thump with several hours of heavy snow.

Yes.

Forgot that.....thus not all of these are moderate....they can drop a QUICK foot down..ie 12/16/07.

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17 hours ago, ORH_wxman said:

Well we have a couple things going for us....no very strong ENSO....having a strong ENSO event typically eliminates huge seasons for us. (except parts of far NNE/mountains who can sometimes still pull a blockbuster)

Second, I think the -QBO and the more east based nature of the ENSO event as well as the pretty muted PDO signal could help with a bit more ridging in the west...more akin to 2000-2001 than a 2007-2008 style pattern.

 

Obviously we could still completely lay a turd this winter...that's the beauty of the weather....we don't actually know whats going to happen. We can just make educated guesses.

 

 

I'm going to actually have to disagree with most of what you said here.

http://ionlyusethegfs.blogspot.com/2012/04/qbo-aleutian-high-relationship.html

 

First of all, you claim that a negative/easterly QBO is favorable for western ridging. I can't find any evidence or research to support that. The only definitive research I've found regarding the QBO comes from Anthony Masiello. I have posted the link to that. His research shows that in roughly 80% of easterly years the pacific ridge is flatter/displaced further southward. This allows low heights to develop over Alaska. The opposite is true during westerly years.

 

You also mention that this event is east based. Well, that's true, but only when you focus on SST's. Atmospherically, It's very west based. I've posted a graphic of the 850mb wind anomalies so far for this Autumn. It indicates a very west based event with all of the strong easterlies focused west of the dateline. There are actually only a few years I've found that were similar to this year in that regard. The best match was easily 1999, and I've posted the wind anomalies below for comparison, but other years like 1998 and 2011 were quite similar also. What's interesting is that these winters were all quite similar in the pacific. There was a very strong and persistent vortex over Alaska that allowed most of the CONUS to be flooded with warm pacific air for the majority the winter. I think there's a good chance something similar happens this year not only because of how west based the event is but also because this is also an easterly QBO year.

 

You mention 2000-2001 as an analog for the winter. I disagree with that. You claim the PDO was responsible for forcing the ridge in the west that year but if you look at the PDO data you'll see that PDO didn't really begin to rise until AFTER that +PNA/-EPO pattern set up in November/December. I think the reason the ridge developed in the west was because there was a large amount of enhanced westerly flow in the tropics that year. In the graphic I posted below you can see a large band of westerlies draped across almost the entire tropical north pacific with just a small area of enhanced easterlies by the Philippines. This pattern was quite unusual and I can't find another year nina or cold neutral year that was quite like it. If anything, it was more similar to some Nino years.

 

 

compday.tLumURIDzt.gif

compday.HGcmnelQ_f.gif

compday.Jr45NduZaF.gif

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3 minutes ago, CoastalWx said:

That ridging near AK and overall higher heights near the N Pole with troughing near Davis Straits is how I envision it. I'm still not sold on true blocking..but I'll take a decent Pacific. Teleconnects to a SE ridge. 

We don't need true blocking....just serviceable...ie no hostile arctic/Atlantic...but even if we do, those with enough latitude may still be fine.

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6 minutes ago, RUNNAWAYICEBERG said:

Marked my calendar, expecting my foot. 

4 storms that winter here were in the 9-14" range with a 9", 9.5", 10" and 14", The rest were all in the nickel and dime category as some would say falling in the the 3-6" and 4-8" range but we racked up 30 events that winter with 9 of them being in Dec for a total of 137.80"

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3 minutes ago, Tim198 said:

I'm going to actually have to disagree with most of what you said here.

http://ionlyusethegfs.blogspot.com/2012/04/qbo-aleutian-high-relationship.html

 

First of all, you claim that a negative/easterly QBO is favorable for western ridging. I can't find any evidence or research to support that. The only definitive research I've found regarding the QBO comes from Anthony Masiello. I have posted the link to that. His research shows that in roughly 80% of easterly years the pacific ridge is flatter/displaced further southward. This allows low heights to develop over Alaska. The opposite is true during westerly years.

 

You also mention that this event is east based. Well, that's true, but only when you focus on SST's. Atmospherically, It's very west based. I've posted a graphic of the 850mb wind anomalies so far for this Autumn. It indicates a very west based event with all of the strong easterlies focused west of the dateline. There are actually only a few years I've found that were similar to this year in that regard. The best match was easily 1999, and I've posted the wind anomalies below for comparison, but other years like 1998 and 2011 were quite similar also. What's interesting is that these winters were all quite similar in the pacific. There was a very strong and persistent vortex over Alaska that allowed most of the CONUS to be flooded with warm pacific air for the majority the winter. I think there's a good chance something similar happens this year not only because of how west based the event is but also because this is also an easterly QBO year.

 

You mention 2000-2001 as an analog for the winter. I disagree with that. You claim the PDO was responsible for forcing the ridge in the west that year but if you look at the PDO data you'll see that PDO didn't really begin to rise until AFTER that +PNA/-EPO pattern set up in November/December. I think the reason the ridge developed in the west was because there was a large amount of enhanced westerly flow in the tropics that year. In the graphic I posted below you can see a large band of westerlies draped across almost the entire tropical north pacific with just a small area of enhanced easterlies by the Philippines. This pattern was quite unusual and I can't find another year nina or cold neutral year that was quite like it. If anything, it was more similar to some Nino years.

 

 

compday.tLumURIDzt.gif

compday.HGcmnelQ_f.gif

compday.Jr45NduZaF.gif

I think you need to be careful about taking stuff too literally. The -QBO could lead to a few things: a better chance of a -NAO, better chance of an overall -AO, or simply a less hostile +AO/NAO regime. Sometimes when this happens...you have less of a chance of getting a super charged -PNA. 

Part of the easterlies is tropical forcing related. With colder anomalies in the eastern regions, you have a better chance of the wave propagating east. I certainly wouldn't gauge the last 6 weeks too heavily. 

Anyways, I have seen that post before, and he actually came on here and discussed this...so we are well versed in that research. 

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9 minutes ago, dryslot said:

4 storms that winter here were in the 9-14" range with a 9", 9.5", 10" and 14", The rest were all in the nickel and dime category as some would say falling in the the 3-6" and 4-8" range but we racked up 30 events that winter with 9 of them being in Dec for a total of 137.80"

Wow...can't wait for this winter if it is going to be that good there. :o

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1 minute ago, dendrite said:

Wow...can't wait for this winter if it is going to be that good there. :o

If i remember correctly, There were a lot of congrats thrown your way that season................:lol:

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4 minutes ago, dendrite said:

 

Check Ray's date again. lol

He must have a crystal ball, It was more of a reference to SWFE dropping over a foot, Typically not the case in most instances.

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1 minute ago, CoastalWx said:

I think you need to be careful about taking stuff too literally. The -QBO could lead to a few things: a better chance of a -NAO, better chance of an overall -AO, or simply a less hostile +AO/NAO regime. Sometimes when this happens...you have less of a chance of getting a super charged -PNA. 

Part of the easterlies is tropical forcing related. With colder anomalies in the eastern regions, you have a better chance of the wave propagating east. I certainly wouldn't gauge the last 6 weeks too heavily. 

Anyways, I have seen that post before, and he actually came on here and discussed this...so we are well versed in that research. 

It could, but you have to remember that the pacific/EPO is more strongly correlated to temps than the AO or NAO. For example, the AO was negative for almost the entire winter of 2012-13 yet that winter was warm for almost the entire country thanks to the pacific. December 2001 had a negative AO AND NAO and was the warmest December on record for New York City until 2015. The list goes on...

 

I know the easterlies are forcing related, but look, for example, how the very east based easterly QBO years, the ones that failed to produce and Alaskan vortex were behaving compared to this year, It's RADICALLY different. I think a six week period is more than enough time to gauge how the atmosphere is behaving.

 

 

bdpwkCMuJp.png

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3 minutes ago, RUNNAWAYICEBERG said:

Hiw do you guys determine the QBO state and determine its projection over several months when its relatively unknown to simulate on models, just a few can do it too. 

You sort of project out given it's behavior. Right now, the 30mb value is decreasing albeit perhaps at a more slowly rate. The 50mb value is also decreasing slowly. My guess is that 30mb value decreases a bit more and flattens out in winter..50mb continues to decrease..but not sure how fast. So I think we have some confidence that the QBO is going to be negative overall. Remember this is only one metric. It very well could mean little to nothing....the atmosphere has a lot of variables that dictate hemispheric patterns. Some are more important than others.

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17 minutes ago, dryslot said:

4 storms that winter here were in the 9-14" range with a 9", 9.5", 10" and 14", The rest were all in the nickel and dime category as some would say falling in the the 3-6" and 4-8" range but we racked up 30 events that winter with 9 of them being in Dec for a total of 137.80"

I always prefer to play with fire. Dont care if I mix and rain as long as theres another chance coming a few days later hehe. So yea, I’ll take action and tip toeing the gradient over cold and dry deep deep troughs. 

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Just now, Tim198 said:

It could, but you have to remember that the pacific/EPO is more strongly correlated to temps than the AO or NAO. For example, the AO was negative for almost the entire winter of 2012-13 yet that winter was warm for almost the entire country thanks to the pacific. December 2001 had a negative AO AND NAO and was the warmest December on record for New York City until 2015. The list goes on...

 

I know the easterlies are forcing related, but look, for example, how the very east based easterly QBO years, the ones that failed to produce and Alaskan vortex were behaving compared to this year, It's RADICALLY different. I think a six week period is more than enough time to gauge how the atmosphere is behaving.

 

 

bdpwkCMuJp.png

Right, we aren't focusing on the AO/NAO necessarily for temps. But having a less hostile AO/NAO also means that the SE ridge is helped kept in check. Obviously the further south you are in latitude...the more help you need when Nina usually has a SE ridge. 

We'll definitely need to watch the tropics. Right now, the euro slowly migrates the forcing east both in terms of MJO and 850 easterlies.

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2 minutes ago, dryslot said:

He must have a crystal ball, It was more of a reference to SWFE dropping over a foot, Typically not the case in most instances.

I mean it's basically an overrunning event with CAD/in-situ CAD in place. So you're limited on ratios and the amount of upglide which basically caps you at a max potential QPF and snow total. Obviously you need the secondary redevelopment to keep the snow going longer for the bigger totals.

Even if we start off with an arctic cold dome in place and good snow growth eventually the midlevels favor a more dense snow or even sleet to knock down that fluff a bit.

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51 minutes ago, dryslot said:

Yes, Most of these systems originate in the SW and move NE and off the NE coast, If your on the northern side of the front, They can produce moderate snows with the warmer air riding over the top of the cold air at the surface.

 

45 minutes ago, 40/70 Benchmark said:

The synoptic mechanics of it are that the low redevelops into a triple point just near the south coast from the surface up, due to the immense confluence to the northeast (high)....thus the capacity of the high to negate the vestigial WAA from the parent low is attenuated with height...ie the profile is slanted. The surface remains colder, while the warmth overtakes the mid and upper levels, hence the sleet...but once sufficient latitude is achieved, the entire column succumbs to the colder redevelopment.

The latter point will occur at a lower latitude relative to that this season, this year imho.

 

43 minutes ago, ORH_wxman said:

A good high to the north also enhances the frontogenesis...it's what helps a mundane transition event (or mundane overrunning event if you stay all snow) turn into a big front end thump with several hours of heavy snow.

 

Great discussion, y'all. Thanks for educating me some on SWFEs and explaining the synoptic behind them. 

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2 minutes ago, WxBlue said:

 

 

 

Great discussion, y'all. Thanks for educating me some on SWFEs and explaining the synoptic behind them. 

I'm sure you had some good CAD events down in NC...although it seems they've been more infrequent lately compared to the early days of these forums on AOL/TWC/WWBB.

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17 minutes ago, dendrite said:

I mean it's basically an overrunning event with CAD/in-situ CAD in place. So you're limited on ratios and the amount of upglide which basically caps you at a max potential QPF and snow total. Obviously you need the secondary redevelopment to keep the snow going longer for the bigger totals.

Even if we start off with an arctic cold dome in place and good snow growth eventually the midlevels favor a more dense snow or even sleet to knock down that fluff a bit.

Yeah, Most of these fall in the 7-10:1 ratio range that i have seen when i have taken core samples, Morerso then the 12:1 type stuff or higher especially here in the coastal plain.

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11 minutes ago, dendrite said:

I'm sure you had some good CAD events down in NC...although it seems they've been more infrequent lately compared to the early days of these forums on AOL/TWC/WWBB.

Oh absolutely. Appalachians of western NC are good for fun CAD events over the Piedmont of Carolinas and Virginia, but we've been struggling lately because we kept losing full cold air column right when we get the moisture to move in. Folks in SE forum will always look for -AO/-NAO signal to get some blocking so they can lock in the cold air and score big totals. Been several years since we had a favorable -NAO during the heart of winter.

This is more unique to mountains of western North Carolina, including Asheville, but we also get northwest flow snow (NWFS) thanks to the moisture from the Great Lakes. With our mountains slanted from southwest to northeast, orographic lifting can lead to fun 2-6" events in Asheville with higher peaks seeing more than a foot. However, with warming trends occurring, downtown Asheville also haven't seen a good NWFS in several years. At least we still get flurries frequently post-frontal passage and it's gorgeous to see them fall with the sun out to east.

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35 minutes ago, Tim198 said:

I'm going to actually have to disagree with most of what you said here.

http://ionlyusethegfs.blogspot.com/2012/04/qbo-aleutian-high-relationship.html

 

First of all, you claim that a negative/easterly QBO is favorable for western ridging. I can't find any evidence or research to support that. The only definitive research I've found regarding the QBO comes from Anthony Masiello. I have posted the link to that. His research shows that in roughly 80% of easterly years the pacific ridge is flatter/displaced further southward. This allows low heights to develop over Alaska. The opposite is true during westerly years.

 

You also mention that this event is east based. Well, that's true, but only when you focus on SST's. Atmospherically, It's very west based. I've posted a graphic of the 850mb wind anomalies so far for this Autumn. It indicates a very west based event with all of the strong easterlies focused west of the dateline. There are actually only a few years I've found that were similar to this year in that regard. The best match was easily 1999, and I've posted the wind anomalies below for comparison, but other years like 1998 and 2011 were quite similar also. What's interesting is that these winters were all quite similar in the pacific. There was a very strong and persistent vortex over Alaska that allowed most of the CONUS to be flooded with warm pacific air for the majority the winter. I think there's a good chance something similar happens this year not only because of how west based the event is but also because this is also an easterly QBO year.

 

You mention 2000-2001 as an analog for the winter. I disagree with that. You claim the PDO was responsible for forcing the ridge in the west that year but if you look at the PDO data you'll see that PDO didn't really begin to rise until AFTER that +PNA/-EPO pattern set up in November/December. I think the reason the ridge developed in the west was because there was a large amount of enhanced westerly flow in the tropics that year. In the graphic I posted below you can see a large band of westerlies draped across almost the entire tropical north pacific with just a small area of enhanced easterlies by the Philippines. This pattern was quite unusual and I can't find another year nina or cold neutral year that was quite like it. If anything, it was more similar to some Nino years.

 

 

 

 

 

-QBO itself won't help with western ridging (though a flattened dateline ridge would actually correlate to less downstream troughing over the west), but a muted PDO and weaker ENSO- certainly could. The -QBO/Nina combo seems to be pretty favorable in Nina for a gradient type pattern....2011-2012 was a pretty notable exception and to a lesser extent 1998-1999...the QBO that year was fading rapidly though. But many other years had it like '07-'08, '00-'01, '70-'71 and '74-'75. That would be good for snows up in New England if nothing else...esp if those other two factors help mitigate the -PNA somewhat.

 

And why would we care what the atmospheric tropical forcing is doing this early on anyway? We care what it is doing 8-10 weeks from now. Anyways, nothing I'm saying it supposed to be definitive. I'm not an expert LR forecaster...even the best only get it right about 55-60% of the time.

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Classic case of reading what one wants as opposed to what was actually said... 

Will dared say: "....Second, I think the -QBO and the more east based nature of the ENSO event as well as the pretty muted PDO signal could help with a bit more ridging in the west.."  

Now... I'm not here to defend him (I'm sure he's big jerk...) but, that does not mean this: "...First of all, you claim that a negative/easterly QBO is favorable for western ridging..."  

This giant leap, right here... is the source/reason for 99% of social media charged arguments ...  

Can't make it any  more black and what than that, right there.  One guy says A ... reader reads B ...  

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As far as I know, the phase of the QBO has no sensible weather effects for each respective phase. It solely describes the oscillation of the wind patterns that start at 10 mb and with time, usually on the order of two years (quasi biennial), descend down to around 50 mb above the equator. These winds has no effect on middle atmospheric pressure/height patterns, and thus no effect on surface temperature patterns. As I mentioned earlier, for weather in the northern hemisphere, specifically winter, we use the QBO to get a metric of how strong the stratospheric polar vortex is. Simply put, in the westerly phase, the polar vortex is likely to be stronger, and the opposite for the easterly phase (easterly phase is occurring now). I believe, as Tip mentioned, ORH was simply stating that this increases the chances of -AO/-NAO for our winter, thus keeping the SE ridge a bit weaker than it otherwise would be (he was just a big vague with the QBO reference). 

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