CFS Long Range (as in Winter)

[Bob Chill]

I'm not so sure we'd go above climo in a weaker niño. Though there are obviously other factors to consider and the sample is small. Our last 2 weaker ninos we couldnt really get cold air masses and a southern stream to match up. We either had neither or one without the other. In feb 2007 we got the cold air and some blocking but never a good storm track. All our frozen came from a clipper, OV low and an Apps runner. In 2005 we finally got a quasi southern stream at the end of February but the storms were moisture starved and the airmasses were insufficient.

I'm not confident a low end moderate niño will be a big snow producer. Probably either in the 8-12" range at DCA even with blocking. Or the 12-15" range if we can get a 6" plus event and/or some December or march 3-6" super clipper or fluke.

If you locked in a 1.0 3.4 departure and all other factors were expected to be neutral/climo or at least not hostile, I'd probably go 10-14" at DCA and call it a day.

Very good points.

I'm hanging my hat on the other indices cooperating. Weaker versions of 02-03 and 09-10 (in the indicies dept. not snowfall). My 2 favorite analogs are 86-87 and 06-07. I know 06-07 was a bit of a dog but it could have easilty gone the other way with a little help. I like 02-03 as well. Absolutely not saying that we get a big year. That will take some serious beating the odds.

We'll see how things are looking with the tendencies for the ao/nao in Nov-Dec. If Dec comes in with another big +AO then I'm going to be really worried. Until then I'll remain optimisitic and be just ever so slightly bullish with a slightly above climo snowfall.

[PhineasC]

Very good points.

I'm hanging my hat on the other indices cooperating. Weaker versions of 02-03 and 09-10 (in the indicies dept. not snowfall). My 2 favorite analogs are 86-87 and 06-07. I know 06-07 was a bit of a dog but it could have easilty gone the other way with a little help. I like 02-03 as well. Absolutely not saying that we get a big year. That will take some serious beating the odds.

We'll see how things are looking with the tendencies for the ao/nao in Nov-Dec. If Dec comes in with another big +AO then I'm going to be really worried. Until then I'll remain optimisitic and be just ever so slightly bullish with a slightly above climo snowfall.

Let's set the bar at a normal year and forget about the big year. A big year in this area is mostly dependent on getting a couple big storms which are hard to predict.

[Bob Chill]

Let's set the bar at a normal year and forget about the big year. A big year in this area is mostly dependent on getting a couple big storms which are hard to predict.

I wish we could get a normal year for once. My climo is about 22" but for the last decade it's feast or famine. A "normal" year would be a huge win for us.

[gymengineer]

I wish we could get a normal year for once. My climo is about 22" but for the last decade it's feast or famine. A "normal" year would be a huge win for us.

I think "normal" years still seemed crappy, so people tend to think they were worse than what happened. In Rockville, you actually did experience several near normal seasons in the last decade...04/05 and 05/06 were both a bit above 22" in Rockville and 03/04 was around 20" in Rockville.

[brad1551]

This -PDO at the moment does not look like it is going anywhere soon. :-(

[SoCoWx]

this is looking pretty good...was talking to Will about it as well.....I am not that jazzed about having a great winter...fortunately there is not much skill at this point...weak nino after extended nina...strong -PDO regime......2006-07 is probably our best analog right now...68-69 and 51-52 aren't bad...2 opposite examples of blocking versus not much blocking.......If I had to forecast right now I'd probably go for a +1 to +2 winter with 10" at DCA...hope I am wrong...of course that would be better than last winter...goes without saying...we should get a period of blocking...likely later in the season...hopefully we can match that up with good source regions for cold and a half decent storm track.....even in October/November I think my skill is only somewhat above flipping a coin....but it is above....but there is a lot of room for me to bust badly....

No offense, but I hope your dead wrong. Dead wrong all over. Those analogs scream a repeat of last Winter for southern VA. The winter of 06-07, we only had half an inch of snow the entire Winter. Missed the February storm. And aside from February, it was pretty much a torch in this neck of the woods.

[SoCoWx]

Persistence is a b-itch as well. I hope I am wrong too. But I definitely wouldn't favor a big winter unless niño can get in the moderate- strong range. I'd probably lean warm too. That isn't any bold prediction of course. Winter generally sucks here.

Well, in this particular part of VA, the average winter high is about 48/49. The average snowfall is 10". If I could have a normal winter like that, then I'd be happy. It's not a lot. Certainly not cold or snowy to many people on these forums who expect much more. But for southeastern VA, that would count as a decent winter.

Hell, I'd even settle for 6 inches of snow throughout the winter. But anything less than that, and it starts to become painfully uneventful. 2008-2009 wasn't bad. A little weird. But not bad. We had some cold. It snowed twice in November which was odd. Then it basically didn't snow the entire Winter. Then snow again around the first of March and we got 3".

[mitchnick]

Persistence is a b-itch as well. I hope I am wrong too. But I definitely wouldn't favor a big winter unless niño can get in the moderate- strong range. I'd probably lean warm too. That isn't any bold prediction of course. Winter generally sucks here.

after last year, even a normal snowfall year will seem like a big year to most

I know it will for me

[Bob Chill]

Persistence is a b-itch as well. I hope I am wrong too. But I definitely wouldn't favor a big winter unless niño can get in the moderate- strong range. I'd probably lean warm too. That isn't any bold prediction of course. Winter generally sucks here.

One good miller A can really change totals though. I totally agree that we'll be a bit warmer than norm this winter. It's almost a given nowadays. There's no reason to dismiss the possibility of a sizeable event in a Nino and we can get a good shot at a miller A.

[ORH_wxman]

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

I think 2/24-25/05 was the closest we came to achieving that...that looked like it could be really good but it really kind of crapped out at the last second. Still a half decent event, but mostly a footnote rather than anything worthy of KU discussion. It never looked like a blockbuster, but perhaps bordelrine cat 1 KU a couple days out.

[Huffwx]

BWI has been normal or below in every weak niño except 77-78 and that was the beginning of a big +PDO regime and 2nd year nino with a massive cold air dump. Pretty unlikely we will see a winter like that. If niño is weak no reason to expect a big winter. Normal is achievable though.

What are you using to define a moderate el nino-- what years? Is it 1.2--

[mitchnick]

I think 2/24-25/05 was the closest we came to achieving that...that looked like it could be really good but it really kind of crapped out at the last second. Still a half decent event, but mostly a footnote rather than anything worthy of KU discussion. It never looked like a blockbuster, but perhaps bordelrine cat 1 KU a couple days out.

looking back at Wunderground's history at BWI on those dates, it wasn't a bad storm at all for us

I just wish I could remember it

[Ian]

im pulling 2002 up all over the place in various looks at ytd climo etc recently

ill go with it.

[Ji]

Discouraging prospects for winter again and time is running out to get a moderate el niño. Maybe we can hope for a jan 82 event minus the plane crash

[Huffwx]

The storm a few days later -- Feb 28 was the best one down my way. We pulled 7 inches from .9 (all snow save a little drizzle late afternoon) closer to 10 inches in the higher elevations.

[easternsnowman]

Weak ninos are usually pretty good from philly north.

[Ellinwood]

Weak ninos are usually pretty good from philly north.

That's great because we all live from Philly north.

[easternsnowman]

That's great because we all live from Philly north.

Sorry about that, I do hope you guys get a good winter!

[mitchnick]

Weak ninos are usually pretty good from philly north.

if either CFS model is to be believed, both continue to show (as they have for months) that there will be below normal precip for the winter from PA north

of course, who knows if either is right but it's not something I'd like to consistently see on long range models if I lived PA north

[SoCoWx]

That's great because we all live from Philly north.

What the blue pony said.

[usedtobe]

Weak ninos are usually pretty good from philly north.

Not really, since 1950 there have been 9 ninos with the 3 month 3.4 temp anomaly at 1C or less and only 2 or the 9 were above normal at nyc which is north of PHL. Bos is almost a toss us but slightly favors below normal years if you use the median but two years were so far above normal that the mean is above normal for BOS. In reality we need more years than 9 to know for certain how a weak nino impacts anyone.

[easternsnowman]

Not really, since 1950 there have been 9 ninos with the 3 month 3.4 temp anomaly at 1C or less and only 2 or the 9 were above normal at nyc which is north of PHL. Bos is almost a toss us but slightly favors below normal years if you use the median but two years were so far above normal that the mean is above normal for BOS. In reality we need more years than 9 to know for certain how a weak nino impacts anyone.

I guess I was looking at the last one in 2004-2005.

[ORH_wxman]

I guess I was looking at the last one in 2004-2005.

'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.

[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.

[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.