2015-16 Winter Pattern Discussion

[snowlover91]

I would rather not see any 300+ hr maps to "prove" a theory. All it does is add to the hype that is being conveyed in the post.  As for the first bolded...this is speculation not fact. What we do know is this upcoming week temps appear to be near normal with a trend to go above normal before another frontal system passes bringing the temps back to normal. What happens after that is nothing more than speculation. Period.

Not sure what "hype" there was in my post. I merely stated that the ensembles are in agreement for 9 out of the first 12 days in January being at or BN. That's a fact and not hype or speculation. Now whether or not they verify is up for debate and I don't expect a verbatim verification. What I do look at are the trends shown, which are encouraging and a good sign.

Also the point of this thread is to discuss the winter pattern. Theories and opinions are what we discuss as to whether the pattern will be favorable or not. What happens even 4-5 days out is "speculation" because weather can and does change. That doesn't mean we are to ignore the data we have readily available to look at. Long range ensembles are one tool we can use to help formulate ideas as to how the long range will unfold.

[buckeyefan1]

I'm confused a bit then.  What do you look for 300+hr maps to tell you?

It's not to PROVE anything. You can't prove something that hasn't happened and when each model run (from various sources) shows a different solution it isn't hard to cherry pick a frame to support your theory. The difference is speaking in absolutes on the future when there is enough spread to provide an outcome that is totally opposite. Whether it WILL or WILL NOT happen is yet to be seen. 

[packbacker]

NCrain,

What you are seeing in the maps you posted, is a typical split flow pattern. Notice the high heights along the Canadian west coast. This is the type of pattern we like to see, if we have a cold source region.

Looks great, I just don't buy into a pattern lock in on Jan 10th, thinking it may be more end of Jan. We have had transient cold shots since Nov, why is the one being shown on days 13-15th any different? That's rhetorical, because we don't know yet. We will see.

[franklin NCwx]

Good agreement on high latitude blocking and a much colder/favorable pattern for snow is on the way.

[Bob Chill]

Looks great, I just don't buy into a pattern lock in on Jan 10th, thinking it may be more end of Jan. We have had transient cold shots since Nov, why is the one being shown on days 13-15th any different? That's rhetorical, because we don't know yet. We will see.

 

Agreed. Transitions are rarely clean and pretty. Usually some warning shots and delays. Works both ways. We've had good patterns in place and models break them down too quick. 

 

In this particular case there are some interesting developments though. The blocking regime keeps looking stronger every day. If the high heights do in fact take up as much real estate as being advertised then they are probably there to stay for a while. That process is happening in the medium term and there is just about 100% agreement across the board over the next 7 days. Also, it's not that common to have all major global guidance look about the same (generally speaking) during d7-15 when things start looking really good. This leads to some extra confidence in the long range. And by extra I mean more confident than usual when looking at fantasy progs. We know the drill but it's unusual to see such agreement at range and keeps looking better as we move forward in time. 

 

If the long range pattern verifies, it's unquestionably the best east coast storm pattern we've seen since 09-10 and the early part of 10-11. 

[snowlover91]

Agreed. Transitions are rarely clean and pretty. Usually some warning shots and delays. Works both ways. We've had good patterns in place and models break them down too quick.

In this particular case there are some interesting developments though. The blocking regime keeps looking stronger every day. If the high heights do in fact take up as much real estate as being advertised then they are probably there to stay for a while. That process is happening in the medium term and there is just about 100% agreement across the board over the next 7 days. Also, it's not that common to have all major global guidance look about the same (generally speaking) during d7-15 when things start looking really good. This leads to some extra confidence in the long range. And by extra I mean more confident than usual when looking at fantasy progs. We know the drill but it's unusual to see such agreement at range and keeps looking better as we move forward in time.

If the long range pattern verifies, it's unquestionably the best east coast storm pattern we've seen since 09-10 and the early part of 10-11.

That's what I've been saying as well, the CMC and Euro Ensembles are in great agreement in the long range and it's a good trend to see. It would be different if the ensembles all had different solutions but when all 3 show a similar pattern then confidence is much higher for increased cold. It likely won't be as extreme as the control runs show, however if we do see an SSW mid-January like I think we will then the strong blocking, if it verifies, would likely push the PV towards Hudson Bay which would favor sustained cold.

[snowlover91]

Looks great, I just don't buy into a pattern lock in on Jan 10th, thinking it may be more end of Jan. We have had transient cold shots since Nov, why is the one being shown on days 13-15th any different? That's rhetorical, because we don't know yet. We will see.

Normally I would agree with a delayed pattern; however I think we see an SSW event soon due to the projected warming of the PV and a split or displacement by mid-January is a good possibility. If this does indeed happen it will get much colder sooner and I think this is what the long range ensembles are picking up on. If it doesn't split or gets displaced to the opposite side of the globe it could get ugly, however chances of this seem quite low with no guidance indicating that happening. In 1957-58 the strong December PV weakened quickly in January and we had SSW the end of January. The following February was quite cold in large part due to this event. If we get an SSW to actually happen and a few weeks earlier than 1957-58 then the second half of January and most of February would likely be quite cold. There is always the chance this doesn't happen but the evidence and tools I have access to along with analogs indicate a good possibility.

[CAD_Wedge_NC]

Agreed. Transitions are rarely clean and pretty. Usually some warning shots and delays. Works both ways. We've had good patterns in place and models break them down too quick. 

 

In this particular case there are some interesting developments though. The blocking regime keeps looking stronger every day. If the high heights do in fact take up as much real estate as being advertised then they are probably there to stay for a while. That process is happening in the medium term and there is just about 100% agreement across the board over the next 7 days. Also, it's not that common to have all major global guidance look about the same (generally speaking) during d7-15 when things start looking really good. This leads to some extra confidence in the long range. And by extra I mean more confident than usual when looking at fantasy progs. We know the drill but it's unusual to see such agreement at range and keeps looking better as we move forward in time. 

 

If the long range pattern verifies, it's unquestionably the best east coast storm pattern we've seen since 09-10 and the early part of 10-11. 

Agree 100%

[snowlover91]

The 18z GFS had some interesting trends inside 120 hours. It drops a piece of energy down and out ahead of it has a WSW flow at 500mb causing some light overrunning precip. It doesn't make it far enough and the cold air isn't quite in place, but it's close. Something to keep an eye on, it wouldn't be much but even to see a few flakes or wintry precip this weekend would be great. Euro is dry so take this FWIW. We would need to see more WSW flow at 500mb and a later timing for this system, overnight, to allow longer for the cooler air to filter in and diurnal cooling as well.

[packbacker]

I like what the 18z GEFS is doing days 12+...to bad it's a garbage model though ;-) #legit-NAO

And, no I don't think GEFS is garbage. Op GFS I don't look at hardly.

[snowlover91]

I like what the 18z GEFS is doing days 12+...to bad it's a garbage model though ;-) #legit-NAO

And, no I don't think GEFS is garbage. Op GFS I don't look at hardly.

Would love to see a negative NAO that actually sustains for several weeks or more. I can't remember the last time we had a long lasting one, it's been quite a few years I believe. OP GFS is good for comic relief outside the 180 hour range. It's decent inside 120 hours but outside that too unstable. What do you think about the overrunning hinted at on the 18z GFS? It seems to stem from the piece of energy dropping down and the 500mb flow backing WSW ahead of it. The cold air is marginal but close by, at least something to watch if future runs continue to pick up on this. I would like to see the Euro pick up on this also.

[Stormcatt]

The 18z GFS had some interesting trends inside 120 hours. It drops a piece of energy down and out ahead of it has a WSW flow at 500mb causing some light overrunning precip. It doesn't make it far enough and the cold air isn't quite in place, but it's close. Something to keep an eye on, it wouldn't be much but even to see a few flakes or wintry precip this weekend would be great. Euro is dry so take this FWIW. We would need to see more WSW flow at 500mb and a later timing for this system, overnight, to allow longer for the cooler air to filter in and diurnal cooling as well.

Cmc was the first to show this days ago then lost it.

There is GEFS support . The GEFS has trended wetter the last 6 runs

[fountainguy97]

Yeah snow models have been hinting on a storm in that timeframe good to see it still showing up 114 hrs out

[pcbjr]

Cmc was the first to show this days ago then lost it

PLEASE explain the substance. Pleaseeeeeeeeee

[Stormcatt]

PLEASE explain the substance. Pleaseeeeeeeeee

I was simply pointing out that this has been showing off and on for a while now it's not like it just popped up out of the blue. The cmc showed this possibility for days only to lose it. The GFS has been trending wetter and wetter along the coast the last few runs along with the GEFS

[snowlover91]

PLEASE explain the substance. Pleaseeeeeeeeee

Several days ago the CMC had a storm in the 2-4th timeframe with overrunning precip. It then lost it/suppressed the feature. Now it appears to be bringing it back somewhat and the GFS has been showing some very light qpf. Likely would be a cold rain if we get any qpf but it's close to being cold enough for some flakes. Here is the CMC for the same storm, look how close the 850 line is to the moisture. Boundary layer temps too warm but with evaporational cooling and cold air advection it needs to be watched, especially inside 120 hours.

[pcbjr]

I was simply pointing out that this has been showing off and on for a while now it's not like it just popped up out of the blue

 

 

But what does it mean? We all know what shows, disappears ... shows ......

[Stormcatt]

But what does it mean? We all know what shows, disappears ... shows ......

I got ya sorry next time I'll do a better job of describing. See snowlover91s post

[pcbjr]

Several days ago the CMC had a storm in the 2-4th timeframe with overrunning precip. It then lost it/suppressed the feature. Now it appears to be bringing it back somewhat and the GFS has been showing some very light qpf. Likely would be a cold rain if we get any qpf but it's close to being cold enough for some flakes. Here is the CMC for the same storm, look how close the 850 line is to the moisture. Boundary layer temps too warm but with evaporational cooling and cold air advection it needs to be watched, especially inside 120 hours.

image.png

EXACTLY = substance

[Batman]

First post of the season. The last few days have been the first I have been at all optimistic about winter actually behaving like winter since many winter forecasts were issued in Sept. - Nov. What we all have to remember is that we live in the south and winter behaving like winter does not mean snow storms and constant snow threats. Most of you live north of me, so you are justified in expecting a little more snow the 2" per season that I average. However, I am constantly amazed at how many people on this forum are not satisfied, and in many cases angry if all models, ensembles and teleconnections aren't showing constant 20+ below normal temps and snow chances every 2-3 days. I am excited about highs in the upper 40's to low 50's and lows at or below freezing Friday thru Monday. No this is not the jackpot for winter weather, but it is a HUGE step in the right direction after Christmas weekend highs in the 70s and a true blow torch December.

 

Beyond that, there is mounting evidence (models, ensemble members, teleconnections and indicies) that our weather pattern is changing into one where below normal temps and above normal precip are very likely. Yes, the current 11-15 day shows a chance for above normal for our area, but the forecast discussion even mentions that confidence is below normal because it is not consistent with the ridge forecasted in western Canada at that time. If we can get a ridge established in Western Canada, a -AO as forecasted with an active southern jet, we could all be in business before long. I won't even speculate on the NAO, but it has been showing signs of approaching negative in the long range. Lot's of skilled and respected LR mets (DT, JB, Don. S....) are gaining confidence that a very favorable pattern is on the way for our region. All of this leads me to be very optimistic!

[Cold Rain]

Batman sighting. Good post!

[griteater]

If the long range pattern verifies, it's unquestionably the best east coast storm pattern we've seen since 09-10 and the early part of 10-11. 

This has crossed my mind a few times too Bob.  While we've had a few good winter events, most notably Feb 2014, we haven't actually had a good winter pattern for the SE since the first half of the 2010-2011 winter.

[packbacker]

Would love to see a negative NAO that actually sustains for several weeks or more. I can't remember the last time we had a long lasting one, it's been quite a few years I believe. OP GFS is good for comic relief outside the 180 hour range. It's decent inside 120 hours but outside that too unstable. What do you think about the overrunning hinted at on the 18z GFS? It seems to stem from the piece of energy dropping down and the 500mb flow backing WSW ahead of it. The cold air is marginal but close by, at least something to watch if future runs continue to pick up on this. I would like to see the Euro pick up on this also.

 

I haven't looked at a surface run in a few days, it is curious what you posted to see if simple overrunning could deliver a few flakes.

[Snowless in Carrollton]

First post of the season. The last few days have been the first I have been at all optimistic about winter actually behaving like winter since many winter forecasts were issued in Sept. - Nov. What we all have to remember is that we live in the south and winter behaving like winter does not mean snow storms and constant snow threats. Most of you live north of me, so you are justified in expecting a little more snow the 2" per season that I average. However, I am constantly amazed at how many people on this forum are not satisfied, and in many cases angry if all models, ensembles and teleconnections aren't showing constant 20+ below normal temps and snow chances every 2-3 days. I am excited about highs in the upper 40's to low 50's and lows at or below freezing Friday thru Monday. No this is not the jackpot for winter weather, but it is a HUGE step in the right direction after Christmas weekend highs in the 70s and a true blow torch December.

 

Beyond that, there is mounting evidence (models, ensemble members, teleconnections and indicies) that our weather pattern is changing into one where below normal temps and above normal precip are very likely. Yes, the current 11-15 day shows a chance for above normal for our area, but the forecast discussion even mentions that confidence is below normal because it is not consistent with the ridge forecasted in western Canada at that time. If we can get a ridge established in Western Canada, a -AO as forecasted with an active southern jet, we could all be in business before long. I won't even speculate on the NAO, but it has been showing signs of approaching negative in the long range. Lot's of skilled and respected LR mets (DT, JB, Don. S....) are gaining confidence that a very favorable pattern is on the way for our region. All of this leads me to be very optimistic!

I would be happy with 1/2" of snow every season and we usually can't even manage that ! One of these days i'm going to move to Dallas and hopefully then I can get in on some of the action.

[packbacker]

I like what the 18z GEFS is doing days 12+...to bad it's a garbage model though ;-) #legit-NAO

And, no I don't think GEFS is garbage. Op GFS I don't look at hardly.

 

These are the 5h anomalies of a few popular central NC winter storms in nino's...hmmm  

 

Getting there on the 18z GEFS, would like to see higher heights down in HB.

[snowlover91]

I haven't looked at a surface run in a few days, it is curious what you posted to see if simple overrunning could deliver a few flakes.

It's possible but my main concern is whether the cold would filter in quick enough, we know how that usually works out, not very well. The NAM at 84 shows a WSW 700mb flow over NC and taps into more moisture whereas the GFS is a W flow which would be much drier. I'm using the NAM merely to show what we would want to see if we are to get some qpf into NC for this system, a flatter and westerly 700mb flow like the GFS would keep us dry.

GFS 700mb moisture map

Nam 700mb moisture, notice the increased moisture and WSW flow aloft.

[packbacker]

Would love to see a negative NAO that actually sustains for several weeks or more. I can't remember the last time we had a long lasting one, it's been quite a few years I believe. OP GFS is good for comic relief outside the 180 hour range. It's decent inside 120 hours but outside that too unstable. What do you think about the overrunning hinted at on the 18z GFS? It seems to stem from the piece of energy dropping down and the 500mb flow backing WSW ahead of it. The cold air is marginal but close by, at least something to watch if future runs continue to pick up on this. I would like to see the Euro pick up on this also.

 

SOI looks to go negative and possibly strongly for the next couple of weeks...

 

[snowlover91]

SOI looks to go negative and possibly strongly for the next couple of weeks...

What affect would a negative SOI have on the NAO? I've heard of this index before but do not know much about it or the effects during El Niño.

[deltadog03]

Well, if the weeklies are right, and the ENS are right and we don't produce something....I will be shocked.

[packfan98]

What affect would a negative SOI have on the NAO? I've heard of this index before but do not know much about it or the effects during El Niño.

I'll try on this one. When the soi tanks it usually helps fire up the subtropical jet. Lots of warning bells that are starting to go off for a storm in a couple of weeks with the other indices looking favorable.