CFS Long Range (as in Winter)

[mappy]

What a pleasant post.

If you hadn't quoted it, I wouldn't have had to read it

[FXW176]

Lol, my bad.

[Ji]

winters over

[Midlo Snow Maker]

winters over

I'm hopping on dons -AO train

A thought concerning the prospects for winter blocking...

The June 2012 AO averaged -0.672 and the July AO has averaged +0.09 through July 30. Assuming the AO averages < 0 for the summer (June-August) timeframe, odds would favor the AO's averaging < 0 for the upcoming winter (December-February).

Since 1950, there were 38 cases during which the summer AO averaged < 0. 26/38 (68.4%) saw the winter AO also average < 0.

In cases when the summer AO averaged < 0, a winter AO < 0 was 1.4 times more likely than an AO > 0 during El Niño events. Winter 2009-10 was the most recent El Niño case that saw a negative winter AO.

In contrast, during those 38 cases, a winter AO > 0 was 2.9 times more likely than an AO < 0 during a La Niña. Winter 2011-12 was the most recent La Niña case that saw a positive winter AO.

In sum, if the summer 2012 AO averages < 0 and the upcoming winter experiences an El Niño (or even neutral ENSO conditions), there should be more blocking than last winter. Moreover, a blocky winter would appear more likely than not. Nevertheless, things are not yet cast in stone. Such developments as early-season Siberian snow cover expansion could provide a hint as to how things will turn out during Winter 2012-13.

[Huffwx]

'06-'07 technically qualifies as a 1.0 peak now on the trimonthly when CPC updated its anomalies...however, that Nino was stronger MEI-wise than any of the other weak Ninos...it really ramped up late fall...but it disintigrated very quickly after its peak.

Was 06-07 an east based? I've searched and my results are no-- but for some reason it seems no one really thought it be a good winter to begin with and I can't recall why. That -EPO was nice in Feb, but little or no snow south of DC.

[Bob Chill]

I can't think of a single weak nino where we got a sizeable miller A.

The period from 1/22-30 in 87 dropped almost 30" in rockville. One 14" storm and one 10". I have no idea if they were miller A's though. I like the 86-87 analog alot from an enso perspective. But I'm not expecting 2 storms aoa 10" this winter at all. I just think we may pull off one nice event and a couple nickel and dimers.

Edit:

Looking at my backyard snowfall data for all weak ninos shows that it's pretty much a lock that Dec is going to stink. Most are total shutouts.

[Deck Pic]

The period from 1/22-30 in 87 dropped almost 30" in rockville. One 14" storm and one 10". I have no idea if they were miller A's though. I like the 86-87 analog alot from an enso perspective. But I'm not expecting 2 storms aoa 10" this winter at all. I just think we may pull off one nice event and a couple nickel and dimers.

Edit:

Looking at my backyard snowfall data for all weak ninos shows that it's pretty much a lock that Dec is going to stink. Most are total shutouts.

my problem with 86-87 is 2-fold

1) I think the strength of our Nino especially coming off a stronger 2 year cold period will be weaker than 86-87

2) Winter of 86-87 was coming off a period in which 85/94 months had a +PDO and of the 9 -pdo months not a single one was -1 or less....And of course that winter had a massive +PDO...we aren't likely to see that this winter with a weak nino...probably not even close...so the combo of a worse PAC and a weaker southern stream and more unfavorable storm track makes the 3 big KU's of that winter much more unlikely to repeat this winter imo...I expect as of now we will be warmer and less snowy

[Bob Chill]

my problem with 86-87 is 2-fold

1) I think the strength of our Nino especially coming off a stronger 2 year cold period will be weaker than 86-87

2) Winter of 86-87 was coming off a period in which 85/94 months had a +PDO and of the 9 -pdo months not a single one was -1 or less....And of course that winter had a massive +PDO...we aren't likely to see that this winter with a weak nino...probably not even close...so the combo of a worse PAC and a weaker southern stream and more unfavorable storm track makes the 3 big KU's of that winter much more unlikely to repeat this winter imo...I expect as of now we will be warmer and less snowy

Well put and tough to argue any of it.

Ultimately, our success or failure for this winter will rely pretty much exclusively from hl blocking and some cold air dumps from the ao. It can overcome quite a bit of the strikes against us irt the pac, weak nino, etc.

Even a weak stj can produce when we have a good temp battleground in the middle of the country along with a semi-decent -nao. I'm not sure what the heck has happened to simple overrunning types of events anyway. It seems like everything we track is some sort of moisture starved clipper, perfect timed vorts in split flow, or some sort of big miller A/B. I'll gladly take a weak moisture feed from the stj and an open wave pushing up through the tn valley.

Maybe I'm wrong but it seemed like overrunning 2-4 / 3-5" used to be alot more common than they are nowadays.

[mitchnick]

that cold pool of water in the Pacific west of Mexico has been very persistent through the summer, though it is starting to show signs of weakening near the equator

a number of tropical systems may be the culprit, so I'm hoping those systems in the eastern PAC stop to give NINO 3.4 and 4 a shot at warming faster

[ORH_wxman]

Was 06-07 an east based? I've searched and my results are no-- but for some reason it seems no one really thought it be a good winter to begin with and I can't recall why. That -EPO was nice in Feb, but little or no snow south of DC.

Yes it was. It was a strange Nino in the sense that it strengthened quite rapidly in fall and peaked pretty solidly moderate, but its peak was very short lived and it weakened rapidly after that so its tri-monthly peak wasn't impressive.

February had a pretty darn good longwave hemispheric pattern but we just were never able to get the smaller scale synoptic features to work out for big snows along I-95 east coast.

Its not a bad analog for this year except I don't think we will get as strong as that one on a shorter term peak. There's still a possibility this Nino does get more 3.4-centered as well...but my confidence in that has been waning steadily over the past couple weeks.

[usedtobe]

Yes it was. It was a strange Nino in the sense that it strengthened quite rapidly in fall and peaked pretty solidly moderate, but its peak was very short lived and it weakened rapidly after that so its tri-monthly peak wasn't impressive.

February had a pretty darn good longwave hemispheric pattern but we just were never able to get the smaller scale synoptic features to work out for big snows along I-95 east coast.

Its not a bad analog for this year except I don't think we will get as strong as that one on a shorter term peak. There's still a possibility this Nino does get more 3.4-centered as well...but my confidence in that has been waning steadily over the past couple weeks.

I think that was a nino that the MJO and GWO helped kill or wound if I remember correctly. Klaus Wieckmann gave a talk where he discussed it. I may even have slides from his talk hidden away somewhere. The other killer was the epo which was positive much of the season.

[aldie 22]

2016-17 is our next big year...what does the model say for then?

[Bob Chill]

2016-17 is our next big year...what does the model say for then?

That's easy.....overall above normal temps with about 108" of 240+hr snow and about one tenth of that falling.

Region 3.4 is incredibly similar to the first 6 tri-monthlies of 2006.

[Ellinwood]

Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

[Ian]

im not going to be happy with jan/feb minuses -- i wish you failure

[SoCoWx]

Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

May I inquire as to why the dry? Are you expecting the current warm ENSO phase to have no impact on the storm track? Just curious.

[Ji]

Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

If jan and feb are cold and precip is normal to dry...why below normal snow?

[MN Transplant]

Dangerous talking about negative departures for both Jan and Feb.

All years in the last 3 decades with negative Jan/Feb combos. Snowfall in Jan/Feb (total seasonal).

2010 - 39.5" (56.1")

2004 - 6.2" (12.4")

2003 - 33.2" (40.4")

1996 - 39.0" (46.0")

1994 - 6.6" (13.2")

1988 - 13.1" (25.0")

1987 - 31.1" (31.1")

1985 - 10.0" (10.3")

1982 - 20.6" (22.5")

Quoting my reply to zwyts earlier. When we go negative Jan/feb it is snowy.

[Ellinwood]

May I inquire as to why the dry? Are you expecting the current warm ENSO phase to have no impact on the storm track? Just curious.

I don't think ENSO will have too much of an effect, and I never really do. I just use my "method" and look at the precip analogs.

If jan and feb are cold and precip is normal to dry...why below normal snow?

They're not that cold. I know December isn't the big snow month, but considering I have them coming in more mild I'll assume December ends up with below average snow. If January and February both end up with near normal snow, the season as a whole will still end up slightly below normal.

Quoting my reply to zwyts earlier. When we go negative Jan/feb it is snowy.

EDIT: Had a reply to this but realized that I was in the mindset of having the years starting at the start of the winter in December instead of rolling forward while looking at your Jan/Feb snow years.

[H2O]

2016-17 is our next big year...what does the model say for then?

NAM only goes out to 2014. Gotta wait.

[PhineasC]

Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

Snowfall is imposible to predict. Given that, I like your forecast for a good snow year.

[Ellinwood]

So I've refined my forecast and got my finalized analog years and weighted them (top has highest weight, bottom lowest weight)...

2006

2002

1994

1986

1953

Along with the updated anomalies and precip:

December: +2, normal

January: +1, normal to wet

February: -3, normal

Changed the game up a bit once I got everything weighted to my liking. Most of the U.S. and Canada are above normal in December with little blocking. This is still present but starts to fade in January and the southern U.S. turns neutral to cool. Blocking becomes more evident in February as cold takes over the eastern of the U.S. and most of Canada, with a warm West.

[aldie 22]

So I've refined my forecast and got my finalized analog years and weighted them (top has highest weight, bottom lowest weight)...

2006

2002

1994

1986

1953

Along with the updated anomalies and precip:

December: +2, normal

January: +1, normal to wet

February: -3, normal

Changed the game up a bit once I got everything weighted to my liking. Most of the U.S. and Canada are above normal in December with little blocking. This is still present but starts to fade in January and the southern U.S. turns neutral to cool. Blocking becomes more evident in February as cold takes over the eastern of the U.S. and most of Canada, with a warm West.

I can't wait for my 7" of sleet in February

[mattie g]

I can't wait for my 7" of sleet in February

CAD ftw.

[Deck Pic]

I don't think ENSO will have too much of an effect, and I never really do. I just use my "method" and look at the precip analogs.

They're not that cold. I know December isn't the big snow month, but considering I have them coming in more mild I'll assume December ends up with below average snow. If January and February both end up with near normal snow, the season as a whole will still end up slightly below normal.

EDIT: Had a reply to this but realized that I was in the mindset of having the years starting at the start of the winter in December instead of rolling forward while looking at your Jan/Feb snow years.

doesn't make a ton of sense to me though it may be less of a factor this year....other people agree but they use analogs that are dissmilar enso states...why use all nino analogs if it doesnt matter much?

[Deck Pic]

So I've refined my forecast and got my finalized analog years and weighted them (top has highest weight, bottom lowest weight)...

2006

2002

1994

1986

1953

Along with the updated anomalies and precip:

December: +2, normal

January: +1, normal to wet

February: -3, normal

Changed the game up a bit once I got everything weighted to my liking. Most of the U.S. and Canada are above normal in December with little blocking. This is still present but starts to fade in January and the southern U.S. turns neutral to cool. Blocking becomes more evident in February as cold takes over the eastern of the U.S. and most of Canada, with a warm West.

pretty textbook...I like your numbers for the most part...2006 is the only analog I really agree with...nino needs to get pretty strong for me to like 86/02 imo but they could emerge...nino needs stronger than it was in those actual winters imo for those analogs to work...don't like 53 or 94 at all at this time

[Ellinwood]

doesn't make a ton of sense to me though it may be less of a factor this year....other people agree but they use analogs that are dissmilar enso states...why use all nino analogs if it doesnt matter much?

There's certainly a correlation, but I think people rely on ENSO climo too much when making forecasts. I should clarify that when I mean "relying on ENSO clmo" I mean the typical temperature and precipitation anomalies associated with Nino/Nina years. The blocking, or lack thereof, in the Atlantic along with things like the WPO and EPO have a much greater effect as a whole, but since it's very difficult to estimate those in the long range one has to fall back on things like ENSO and PDO for a starting point. As far as I'm concerned it's still mostly a guessing game even after establishing some of the background elements. It only takes one persistent signal like the +EPO we had this past winter to completely screw up an entire seasonal forecast (much to my dismay last winter ).

I use recent ENSO trends and anticipated values to kind of get a baseline idea, then I use other factors to weed out the ones I want and weigh them according to my confidence in each analog. IMO its good to use as a starting point most of the time, but when it comes to actually picking out specific years and the resulting anomalies I do not weigh the typical ENSO climatology into my forecast. My original analog list had winters that were complete opposites of each other, but after refining my analogs some clearer signals emerged.

EDIT: Fixed the sign of the EPO

[mitchnick]

So I've refined my forecast and got my finalized analog years and weighted them (top has highest weight, bottom lowest weight)...

2006

2002

1994

1986

1953

Along with the updated anomalies and precip:

December: +2, normal

January: +1, normal to wet

February: -3, normal

Changed the game up a bit once I got everything weighted to my liking. Most of the U.S. and Canada are above normal in December with little blocking. This is still present but starts to fade in January and the southern U.S. turns neutral to cool. Blocking becomes more evident in February as cold takes over the eastern of the U.S. and most of Canada, with a warm West.

I'd take my chances with that as far as snowfall goes

hopefully, any surprises this year go in our favor instead of against it like last year

[Bob Chill]

Don S has some great data irt to fall NH snowcover and EC blocking down the road. I plan on paying more attention to Oct snowcover this year. With a weakish nino the most likely scenario we're going to have to rely on the usual suspects to produce for us.

I pulled out 10 of the weaker ninos and looked at blocking in the Jan-Mar. The most recent ones (87,88, 95,07) all pretty much stunk with the monthly NAO index except for 87. Jan-Feb 87 was a great stretch. Feb 07 was "ok" in the blocking department but the year as a whole was a snoozer.

Some of the earlier years (54,59,69,70,77,78) had some great months in the NAO dept. I know this doesn't translate into snow but it's a necessary ingredient more often than not.

[Deck Pic]

There's certainly a correlation, but I think people rely on ENSO climo too much when making forecasts. I should clarify that when I mean "relying on ENSO clmo" I mean the typical temperature and precipitation anomalies associated with Nino/Nina years. The blocking, or lack thereof, in the Atlantic along with things like the WPO and EPO have a much greater effect as a whole, but since it's very difficult to estimate those in the long range one has to fall back on things like ENSO and PDO for a starting point. As far as I'm concerned it's still mostly a guessing game even after establishing some of the background elements. It only takes one persistent signal like the +EPO we had this past winter to completely screw up an entire seasonal forecast (much to my dismay last winter ).

I use recent ENSO trends and anticipated values to kind of get a baseline idea, then I use other factors to weed out the ones I want and weigh them according to my confidence in each analog. IMO its good to use as a starting point most of the time, but when it comes to actually picking out specific years and the resulting anomalies I do not weigh the typical ENSO climatology into my forecast. My original analog list had winters that were complete opposites of each other, but after refining my analogs some clearer signals emerged.

EDIT: Fixed the sign of the EPO

mostly agree