CFS Long Range (as in Winter)

[easternsnowman]

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Great points about the PAC. It's can be a real kick in the teeth when something big and ugly sets up shop. As much as we want it to break down quickly it always ends up being a waiting game and then the risk of the pattern change not cooperating is there.

I have some good data irt Dec probably not being a good month but it isn't organized. Once I put it in "readable" format I'll post it.

TBH- I'm actually hoping for a crappy pac in mid nov - xmas. I wouldn't always say something so crazy but I totally agree that this type of enso pattern will favor a Jan-Feb window more than anything. It would be a kick in the teeth to have the pac, ao, and NAO cooperate for 4-6 weeks before the ss gets going.

It's always such a gamble down here. Subtle missing parts to a pattern can hose us with ease. I'm a bit optimistic for a climo type winter though. Mixed bag of events with a good one tossed in. I don't think going 20"+ in my suburbs is unreasonable at all.

This could be another year where elevation and being further away from the cities makes even a bigger difference than usual.

[donsutherland1]

Wes seemed to focus more on the AO though the AO-NAO often work lockstep.....I can't speak for Wes but when he looks for high latitude blocking I think he is also looking over to the EPO region....

For perspective, I'll repost my scatter diagram for KU snowstorms by ENSO-AO I posted last winter. Unfortunately, there was no need to update the chart following the winter.

[donsutherland1]

Thanks Don. Your grid says a lot but I think it also shows some very loose indication that the AO usually goes negative in a Niño.

Assuming we don't have a strong event in which niño calls all the shots, if it is weak/moderate I think it is almost a foregone conclusion that we will have a blocking pattern at some point and usually with some lasting power. I think there are 2 big questions. 1st, Given the high chance that we don't have a good pacific pattern in December, how long can we expect it to last? Will it be brief? Can we thread the needle even in the bad pattern with a PNA spike or something transient of that nature and take advantage of the brief window? Will we end up punting the 1st half of January as well? And 2nd, once we get a blocking pattern can we capitalize here in the mid Atlantic? And I think a lot of the answer to that is predicated on the strength of the niño with the stronger moderate events giving us a better chance.

I'll try to check the numbers tonight to take a closer look at the ENSO-AO connection. If I recall correctly, the relationship is a weak one, though more episodes of severe blocking have occurred during El Niño winters than La Niña ones. All things being equal right now, I suspect Winter 2012-13 will be kinder to the Mid-Atlantic than the last one was in terms of snowfall. There's still a lot of time for things to change and the evolution of the widespread drought might be a wildcard in the mix of possible variables.

[donsutherland1]

Thanks Don. Your grid says a lot but I think it also shows some very loose indication that the AO usually goes negative in a Niño.

Assuming we don't have a strong event in which niño calls all the shots, if it is weak/moderate I think it is almost a foregone conclusion that we will have a blocking pattern at some point and usually with some lasting power. I think there are 2 big questions. 1st, Given the high chance that we don't have a good pacific pattern in December, how long can we expect it to last? Will it be brief? Can we thread the needle even in the bad pattern with a PNA spike or something transient of that nature and take advantage of the brief window? Will we end up punting the 1st half of January as well? And 2nd, once we get a blocking pattern can we capitalize here in the mid Atlantic? And I think a lot of the answer to that is predicated on the strength of the niño with the stronger moderate events giving us a better chance.

I'll try to check the numbers tonight to take a closer look at the ENSO-AO connection. If I recall correctly, the relationship is a weak one, though more episodes of severe blocking have occurred during El Niño winters than La Niña ones. All things being equal right now, I suspect Winter 2012-13 will be kinder to the Mid-Atlantic than the last one was in terms of snowfall. There's still a lot of time for things to change and the evolution of the widespread drought might be a wildcard in the mix of possible variables.

[PhineasC]

I'll try to check the numbers tonight to take a closer look at the ENSO-AO connection. If I recall correctly, the relationship is a weak one, though more episodes of severe blocking have occurred during El Niño winters than La Niña ones. All things being equal right now, I suspect Winter 2012-13 will be kinder to the Mid-Atlantic than the last one was in terms of snowfall. There's still a lot of time for things to change and the evolution of the widespread drought might be a wildcard in the mix of possible variables.

In my weenie mind I always assumed a mega-drought in the summer and fall led to a wet winter. Rubber-band and all that.

[Bob Chill]

I'm not sure how weak the correlation is...even if we look at all ninos regardless of strength or weather they followed a Nina the evidence is there in the means...

It the magic of an active STJ right? Lower heights through the SE would be naturally balanced with higher heights at higher latitudes.

You can totally envision where the pj and stj are placed when looking at the graphic. It's also easy to see why the northern rockies/plains are typically drier during Nino's.

[Bob Chill]

I went ahead and pulled the NA 500 anoms for Dec & Feb of 86-87 and 06-07. Totally fits what we're thinking irt Dec and Feb.

Another interesting stat is the AO/NAO were positive in December and negative in Feb for both years. 06 was really bad in Dec with a raging +AO but it broke down nicely down the road.

The overall evolution of a Nino post Nina makes alot of sense. 85-86 wasn't a technical Nina but was still a cool enso and was on the heels of a multi-year Nina. It takes time for things to re-organize themselves in the PAC. Especially irt the STJ. I know it's too simplisitic to look at a couple years like 86-87 and 06-07 and think that the upcoming winter is "predictable" but at the very least we can set expectations and wait for the proverbial monkey in the wrenchworks as we get closer.

[usedtobe]

I'm not sure how weak the correlation is...even if we look at all ninos regardless of strength or weather they followed a Nina the evidence is there in the means...

The correlation is pretty weak as I noted in my talk. It's a little higher for the NAO than the AO. The highest correlation is with a PNA pattern.

[usedtobe]

Isn't that for all three months and based on numerical data? I realize monster years skew those composites. I think my suggestion is that there is a correlation between niño and a period of blocking. Especially the later in the winter. I'd guess the correlation from say Jan 15 through Feb 28th is much higher. I think the bad 1st halfs skew the data a bit. I don't think there are more than a few ninos if that that didn't have a blocking pattern at some point, usually extended in the averages.

I do remember you mentioning the weak correlations though.

Probably so but 1972-1973 and 1991-1992 were pretty much positive through the season especially the latter in terms of AO. Also, the correlation can be low if you have a two week period of blocking in a nino season with all the rest of the season having the ao Positive.

I think that happened during the bulk of the crummy everyone along I95 corridor years based on the composite below. The snowy years in El Ninos were much different than the non-snowy ones.

I've never tried to look at ninos following ninas as I'm not sure there are enough years to dray any conclusions.

[usedtobe]

I just looked at the 12 ninos following nina's/negative neutral periods and regardless of strength, they were split down the middle on Dec and January as far as pos/neg nao and 10 of 12 were negative in February with one of the ones that was positive being Feb 2003

If the Nino rises to 1.2 and the QBO goes westerly by winter, then with the solar flux increasing we have a decent chance at a decent back loaded winter. I'm not all that comfortable about what ninos following ninas mean since the ninas themselves can be different and we have a limited number of years. Still I'd 10 out of 12 giving us a negative NAO in Feb than not. MY own view is that a weakly negative AO might not mean much.

[Bob Chill]

I just looked at the 12 ninos following nina's/negative neutral periods and regardless of strength, they were split down the middle on Dec and January as far as pos/neg nao and 10 of 12 were negative in February with one of the ones that was positive being Feb 2003

The thing about Feb 2003 is that + reading for the month was mostly from the strong + during the first week of the month. Jan had a sick stretch of -nao with reading down below -3 and then it rebounded at the end of the month that lasted through mid Feb. The last half of Feb 2003 was in neg territory and that lasted all the way through the first 8 days of March.

I guess what I'm trying to say is that from a practical standpoint, Feb 03 had a very favorable NAO so the + reading for the month doesn't tell the whole story. The entire stretch of Jan - 1st week of March in 03 was really really good irt the NAO. The persistence was definitely biased towards negative with a few short lived strong + periods.

I'd considering sacrificing one of my yard bunnies for another Jan-Mar 03. They eat all my damn vegetable plants anyway so I might sacrifice for other reasons.

[donsutherland1]

In my weenie mind I always assumed a mega-drought in the summer and fall led to a wet winter. Rubber-band and all that.

2/3 of the 30 driest summers wound up also being among the 50 driest winters (CONUS). Whether or not fall was dry was not a big factor.

[donsutherland1]

Some numbers on the ENSO and AO.

December, January, February (1950-2012) when the ENSO R3.4 Anomaly was +0.50°C or above:

Mean AO: -0.489

- 57% days had an AO < 0

- 38% days had an AO of -1 or below

- 13% days had an AO of -3 or below

- 43% days had an AO > 0

- 25% days had an AO of +1 or above

- 4% days had an AO of +3 or above

Ratios:

AO- : AO+: 1.3 days

AO -1 or below : AO +1 or above: 1.5 days

AO -3 or below : AO +3 or above: 3.2 days

December, January, February (1950-2012) when the ENSO R3.4 Anomaly was -0.50°C or below:

Mean AO: -0.235

- 54% days had an AO < 0

- 34% days had an AO of -1 or below

- 8% days had an AO of -3 or below

- 46% days had an AO > 0

- 26% days had an AO of +1 or above

- 4% days had an AO of +3 or above

Ratios:

AO- : AO+: 1.2 days

AO -1 or below : AO +1 or above: 1.3 days

AO -3 or below : AO +3 or above: 1.9 days

In sum, the incidence of AO- and AO+ days was similar in El Niño or La Niña winters. Severe blocking (AO -3 or below) was more than three times more likely during El Niño winters than La Niña winters.

[usedtobe]

Yeah. Our sample size is pretty bad. So there is no way I can really glean any sort of rule. Just maybe a tendency. Of course then we need the timing and the setup and all the details to line up.

Re: the QBO. Wont it still be easterly or neutral by winter?

July will mark the 12th straight easterly qbo month. the last two lasted 14 and 15 months but they can last longer and the one before it last 18 months. We probably switch to westerly sometime around OCt or November. With the solar cycle being on the rise, a westerly qbo might be better at getting a late season AO and NAO through a stratospheric warming event than an easterly one. That said, the AO and NAO are sort of a crap shoot this far in advance.

[aldie 22]

After being on here for so many years I find myself getting less excited each year with the lead up to winter...you just resign yourself that our area generally has a better chance at lackluster vs. blockbuster...no such thing as normal as far as I have seen. I'm hopeful that this won't be a repeat of last year but sometimes you just never know....I still love me some snow and cold though

[WxUSAF]

1983,1993, 2003 = 2013 big snow. 1 time it's a fluke, 2 your on to something & 3 is a pattern.

[North Balti Zen]

When you quote him...it defeats the purpose of the "ignore" function for some of us...

[ORH_wxman]

New Euro SIPS (still not out publically on the ECMWF.int site but should be soon) has a mean around 1.2C or so for the Nino on the monthly peak...which for trimonthly would probably be about 2 tenths lower...so its definitely leaning toward a weak Nino more than it has been from the June and May runs. That is not as favorable for DC as a 1.3-1.8 type peak.

However, the Euro SIPS has two clusterings of values...the larger cluster is around 0.9C and the smaller cluster is around 2.1C...very far apart in their values. This shows a lot of uncertainty in the development of this Nino. I am definitely leaning toward the larger cluster at the moment, but its very possible this could strengthen rapidly in latter August and September once this unfavorable pattern wanes. We'll just have to wait and see. I think we'll have a pretty good idea of whether we can eliminate a peak >1.5C or not by the end of August.

[WxMidwest]

One would think it would be hard to get a Nino to peak out above a 2.0C SST anomaly, during a -PDO cycle... Concensus Weak, maybe low-end moderate at most. Wouldn't be surprised if it tended to be more of a Modoki/Central Pacific Nino instead of your traditional...

[mitchnick]

gotta' like what the CFS has been showing now for a month+ and how the CFS2 is evolving toward a colder look as well

time to start buying nat gas futures

[donsutherland1]

gotta' like what the CFS has been showing now for a month+ and how the CFS2 is evolving toward a colder look as well

time to start buying nat gas futures

The trend on the CFSv2 is encouraging. Should the winter be blocky, the eastern U.S. will have a good chance of averaging cooler than normal. The area covered by cold anomalies will probably be less expansive than that for winters 2009-10 or 2010-11, as the blocking for those two winters was extreme. Perhaps cold anomalies will cover a similar area +/- a modest amount as one saw during the 2002-03 winter. Whether the drought expands eastward could have an impact on precipitation and opportunities for snowfall. Of course, a lack of blocking would result in a much warmer outcome, but for now the model trends are encouraging.

[Ellinwood]

gotta' like what the CFS has been showing now for a month+ and how the CFS2 is evolving toward a colder look as well

time to start buying nat gas futures

Let's take a look at CFS verifications from say, oh February for the late spring into early summer:

Now let's compare it to the actuals...

May-Jun-Jul (to date):

Much, much too cold across most of the CONUS and central Canada, and I hardly think that Jun-Jul-Aug is going to come in near normal across most of North America.

The CFS has been consistently too cold for awhile, especially once you get more than a couple of months into the future. I really wouldn't be giving the CFS any weight WRT the actual forecast anomalies.

Now, the CFSv2 I'd give some weight to, but I definitely wouldn't concentrate on it.

[donsutherland1]

Now, the CFSv2 I'd give some weight to, but I definitely wouldn't concentrate on it.

I agree. If I recall correctly, the CFS will be discontinued after October. Overall, I don't believe that model has done well for the most part. The CFSv2 has fared better.

[mitchnick]

Let's take a look at CFS verifications from say, oh February for the late spring into early summer:

Now let's compare it to the actuals...

May-Jun-Jul (to date):

Much, much too cold across most of the CONUS and central Canada, and I hardly think that Jun-Jul-Aug is going to come in near normal across most of North America.

The CFS has been consistently too cold for awhile, especially once you get more than a couple of months into the future. I really wouldn't be giving the CFS any weight WRT the actual forecast anomalies.

Now, the CFSv2 I'd give some weight to, but I definitely wouldn't concentrate on it.

otoh, CFS1 hit with darn good accuracy for a seasonal forecast last year in this time frame as well as 09/10 winter; here are its predictions for winters of 09/10 and 11/12 from the first week of August

[Ellinwood]

otoh, CFS1 hit with darn good accuracy for a seasonal forecast last year in this time frame as well as 09/10 winter; here are its predictions for winters of 09/10 and 11/12 from the first week of August

"darn good accuracy" may be a subjective term... I prefer "okay":

Don't get me wrong, it's okay at picking out the pattern itself... I'm just saying I have zero confidence in the actual anomalies it shows.

EDIT: Granted, it did a real sh**ty job at picking out the pattern for this summer, so it's kind of hit or miss WRT the pattern as well.

[Ellinwood]

Also, for the sake of not cherry-picking verifications, here's the winter 2010-11 forecast from August and the verification to go with the other winters:

Not so good.

[griteater]

Kind of an interesting observation.

Re: The dynamical model averages(statistical models arent very good) in the last 4 Niño events.

2002, 2004, 2006, 2009 all had exactly a .2 degree cold bias for DJF tri monthly in the July Averages. Probably coincidence but would make

This niño a 1.1 which is still risky territory but could be decent.

NASA and COLA CCSM3 (which is a similar coupled model to the CFS) are warm biased models so I wouldnt put too much stock in their exact output right now. When you account for their bias, low 1's seems reasonable. I don't think there is a lot of current evidence that niño will go above 1.2 but I hope I am wrong. That is still risky territory for good snow though at least one month or 2 should be cold.

Good analysis. A blend of the EUROSIP and the Dynamical Model Averages is probably the best we've got with respect to ENSO projections.

[Bob Chill]

Even a nino in the 1 - 1.3 range isn't something that's concerning. At least I don't think it is. At the very least it opens the door for potential and we really need that coming off the heels of a multi-year cold enso.

Probably going to get going later rather than soon but at some point we will see an active stj. Then it comes down to the setup. I see no evidence that points towards another crappy +AO/NAO type of winter. We'll have our chances this winter. It's foolish to ever predict a big winter in our area because the odds are so bad but there is no reason to believe we can't go slightly above climo with at least one 6"+ storm.

[mitchnick]

"darn good accuracy" may be a subjective term... I prefer "okay":

Don't get me wrong, it's okay at picking out the pattern itself... I'm just saying I have zero confidence in the actual anomalies it shows.

EDIT: Granted, it did a real sh**ty job at picking out the pattern for this summer, so it's kind of hit or miss WRT the pattern as well.

although I didn't say it, I was being Mid-Atlantic centric wrt the CFS seasonal forecasts of 09/10 and 11/12

it still did OK with the general pattern in those years, though it did blow 10/11

I expect we could all agree on the general accuracy of the seasonal models at this time range and the CFS has had its share of big misses with the rest of them, but its forecast at this range for 2 out of the last 3 winters for our region have been pretty good imho, so I'm liking what I see, which is what I said in my post on Page 4

moreover, considering we're talking a NINO this year, in one strength or another, and the trend on the CFS2, I think we do have better than equal chances of finally waking from last winter's nightmare

[Ellinwood]

although I didn't say it, I was being Mid-Atlantic centric wrt the CFS seasonal forecasts of 09/10 and 11/12

it still did OK with the general pattern in those years, though it did blow 10/11

I expect we could all agree on the general accuracy of the seasonal models at this time range and the CFS has had its share of big misses with the rest of them, but its forecast at this range for 2 out of the last 3 winters for our region have been pretty good imho, so I'm liking what I see, which is what I said in my post on Page 4

moreover, considering we're talking a NINO this year, in one strength or another, and the trend on the CFS2, I think we do have better than equal chances of finally waking from last winter's nightmare

lol, that's a small difference in perspective between us

As far as the CFS is concerned, there really isn't much (if any) value in using that model anymore. It's going down in October, anyway... might as well just stick with the CFSv2 and other models that aren't the CFS (at least those that aren't as bad or worse as the CFS). IMO, using the CFS 4-6+ months in advance is like using the JMA for a winter storm 7 days out (or at any time, for that matter ).