My thoughts about winter

[Nikolai]

lol @ people arguing for a robust ST jet this winter

it is not happening

this is a major symptom of the ongoing pattern

given the severity of the drought what is currently a symptom will soon become one of many causes of a drought over most of the SE this winter (drought begets drought)

this kind of extreme dryness over TX right now is a major indicator that the STJ will be mostly absent this winter

[ORH_wxman]

I was waiting for this to actually happen before replying, but here's my reasoning:

That's not a typical Niña MJO... Like I said, when all is said and done the Niña's main impact on this winter will be to strengthen the polar jet, NOT to weaken the southern jet... Could lead to moisture-laden superbombs if phasing happens... a big IF, since phasing requires two storms to coincide in positioning on the streams.

That doesn't mean the winter is going to produce consistent MJO waves near the dateline.

There's very few Ninas that ever had an active STJ.

[Bob Chill]

There's very few Ninas that ever had an active STJ.

I'm only half way through checking each one individually and I can't find one so far. I would think at the very best, we can only really hope for STJ interaction on NS vorts that round the base of the trough. The odds are always stacked against proper placement and timing.

Watch the timing work perfectly this winter but have the trough axis too far the the W and we end up with above normal precip but the wrong kind. lol

[ORH_wxman]

I'm only half way through checking each one individually and I can't find one so far. I would think at the very best, we can only really hope for STJ interaction on NS vorts that round the base of the trough. The odds are always stacked against proper placement and timing.

Watch the timing work perfectly this winter but have the trough axis too far the the W and we end up with above normal precip but the wrong kind. lol

'95-'96 had an active STJ at times as a weak Nina. Esp in Feb '96.

[Bob Chill]

'95-'96 had an active STJ at times as a weak Nina. Esp in Feb '96.

I hadn't got that far yet but yes, that was a pretty active year. However, precip in the SW, TX, and LA was below normal in both Jan and Feb.

I think 96 is more of an example of well timed phasing than it was an overall active STJ. The + precip anolmolies are pretty much just up the EC which would imply phasing at the base of the trough more than the STJ itself being active because if it was, we would see good precip in the SW and gulf coast right?

[tacoman25]

The NAO has some persistence to it from winter to winter, and the Atlantic SST's are where it "saves" that persistence during the spring and summer. (Note that we are now in September, so the files have been loaded already, so to say... the current SST's are of no consequence). Granted, the persistence is fairly weak, but going with the same state as last winter is still slightly better than flipping a coin, given no other information... it is even better, though not overwhelmingly so, if the SSTs of the spring and summer match the pattern from the last winter. This year the April-August SST's are pointing negative once again, yet not as overwhelmingly so as last year. Sunspot area, which is what I go by (since it is a more reliable indicator of solar activity than sunspot number and the record goes farther back than 10.7 flux or Ap index), has gone up, but is still well below every cycle (since 1874) except for #14 (1910's... during which there was a pretty epic string of winters if COOP data is to be believed). What interests me more, though, is the 3-5 year lag in the long-term pattern... the magnetism had a step change in October 2005, and it wasn't until spring 2009 that we really started to see the effects on the AO. If this is true, then next winter corresponds to an even lower point in the magnetic field than last winter did, and it corresponds to the very depths of the SSN/10.7 minimum. Right now we are at the top of the 6-7 month pseudocycle that the Sun has experienced lately... I forsee a drop in solar activity starting in October and continuing through at least January, with the sunspot number bottoming out in January or February before rising again. Not quite as well-placed as 2010-2011's drop, but still a pretty good time to have one. Oh, and to anyone using the Holton-Tan relationships, you need to still count this as a solar minimum... it is getting closer to an in-between, but I don't think we will see true "maximum" (by late 20th century standards) conditions for a long time (at least 20 years, possibly much longer). Based on multiple factors (including the smashed-record --NAO summer), I believe there will be a -NAO block averaging about -1.5. It will be overwhelmingly west-based... the indicators for a WEST-BASED -NAO are nearly off the charts. Based on the same summer correlation (which is much higher at .35 for the AO [it was around .1 for the NAO]), and the summer AO, which was third only to 2009-2010 and 1958-1959, I think the AO will average around -2.5. The EPO is definitely the teleconnection to watch... based on the +OLR in the Indian Ocean, the EPO should be raging negative... but it's not, currently. However, when the genuine wildcard is whether there will be a double-block or a very rare triple-block dominant pattern, things are still looking up... especially because the EPO is notoriously difficult to predict.

EDIT: Also, a -PNA average is pretty much a given. The STJ will be more active than last winter but less so than 2009-2010. That leaves plenty of room for error lol. Something tells me the STJ will be more active than the borderline weak/moderate Niña would suggest, though.

tl;dr: It's gonna be cold.

One thing I didn't see explained here: why do you think the indicators for west-based -NAO are so strong? As opposed to more east-based?

[icebreaker5221]

In addition to numerous lakes cutters, I have a feeling that the mid-range storm on todays GFS is a good example of what we'll be seeing in terms of east coast action this winter: a storm dominated by the northern stream, little precip to the south, and late development off the coast. Could work well for Boston, not so great for DC.

[easternsnowman]

In addition to numerous lakes cutters, I have a feeling that the mid-range storm on todays GFS is a good example of what we'll be seeing in terms of east coast action this winter: a storm dominated by the northern stream, little precip to the south, and late development off the coast. Could work well for Boston, not so great for DC.

Being a nina my takes is that anyone south of the M/D line would need a strong neg NAO and good timing to have a decent snowfall year.

[HM]

What interests me more, though, is the 3-5 year lag in the long-term pattern... the magnetism had a step change in October 2005, and it wasn't until spring 2009 that we really started to see the effects on the AO. If this is true, then next winter corresponds to an even lower point in the magnetic field than last winter did, and it corresponds to the very depths of the SSN/10.7 minimum. Right now we are at the top of the 6-7 month pseudocycle that the Sun has experienced lately... I forsee a drop in solar activity starting in October and continuing through at least January, with the sunspot number bottoming out in January or February before rising again.

Okie, I agree with you about the next drop in the ap/imf/solar wind comes mid-January. We are going to be on the rise here through the next couple of weeks with the recent string of activity. We reached a raw solar wind minimum in early September and we will likely recover substantially through the next few months before we start to tumble again this winter. The question is: how will this affect the AO November and December? Also, as we near solar max, I suspect this 6-7 month pattern is over as we continue to get favorable geoeffective sunspots/CH. Do you agree?

Having said that, the L&P charts are still breathtaking.

[ORH_wxman]

I hadn't got that far yet but yes, that was a pretty active year. However, precip in the SW, TX, and LA was below normal in both Jan and Feb.

I think 96 is more of an example of well timed phasing than it was an overall active STJ. The + precip anolmolies are pretty much just up the EC which would imply phasing at the base of the trough more than the STJ itself being active because if it was, we would see good precip in the SW and gulf coast right?

Active STJ doesn't have to mean above avg precip in TX and LA...it helps them but its not always true. The storm nuances within in the STJ can make precip patterns inconsistent if you are just looking at individual years. How the polar jet interacts with the STJ can make or break precip patterns.

Look at the zonal wind anomalies in the subtropical pacific southwest of California and beyond.

[okie333]

That doesn't mean the winter is going to produce consistent MJO waves near the dateline.

There's very few Ninas that ever had an active STJ.

Whoah hold it there... I didn't mean it would be hyperactive, like 2009-2010... I just meant I don't think the ENSO is going to have a noticeable effect on its strength... like the STJ will look like something from a near-zero positive neutral ENSO pattern.

[okie333]

One thing I didn't see explained here: why do you think the indicators for west-based -NAO are so strong? As opposed to more east-based?

The SST correlations are almost exactly the same as would be expected for a -NAO this winter... except they are displaced westward, at least compared to last summer's textbook pattern.

Active STJ doesn't have to mean above avg precip in TX and LA...it helps them but its not always true. The storm nuances within in the STJ can make precip patterns inconsistent if you are just looking at individual years. How the polar jet interacts with the STJ can make or break precip patterns.

Look at the zonal wind anomalies in the subtropical pacific southwest of California and beyond.

So I take it you agree with me? Also, enlighten me as to the zonal wind anomalies... I can see what looks to be the beginning of a Pineapple Express in the upper troposphere; is that what you are referring to?

[tacoman25]

The SST correlations are almost exactly the same as would be expected for a -NAO this winter... except they are displaced westward, at least compared to last summer's textbook pattern.

Hmm, how strong is the correlation with SST placement in summer and the NAO the following winter?

Also, something I've noticed is that years/winters with very +SOI tend to favor blocking further westward. See: 1903-04, 1910-11, 1917-18, 1950-51, etc. 2010-11 saw this as well. The +SOI was very high at this time last year but has been much lower this year. In addition, the -ENSO anomalies seem to be centered further east this year. This is pointing to me that the the blocking may not be as far west as last winter, both in the Pacific and Atlantic sides.

[ORH_wxman]

Whoah hold it there... I didn't mean it would be active, like 2009-2010... I just meant I don't think the ENSO is going to have a noticeable effect on its strength.

Why not?

La Nina suppresses the STJ. Why is this one going to be significantly different?

There hasn't been one since spring of 2010 (well there's been one but its been so weak that it has no effect on our weather). I'm just wondering what you think might happen that will cause it to become active again this winter. I wasn't suggesting a '09-'10 STJ either, just simply an active one for at least part of the winter ala 1995-1996.

Wes mentioned the QBO possibly initiating more convection further east than a typical Nina which could make the STJ a little more active for brief periods...but I'm not a total expert on that relationship on the shorter time scale.

[uncle W]

the MEI index says we are in La Nina now while the oni index says we started the fall to La Nina...last year at this time there already was a strong La Nina and the winter was great...La Nina winters usually have one great 15-30 day period when it's very cold and snowy...I think the la nina could peak between -0.7 and -0.9 on the oni index...That would put 2011-12 close to some of these years......

1956-57...-0.5

1961-62...-0.4

1962-63...-0.6

1964-65...-0.8

1966-67...-0.4

1967-68...-0.7

1971-72...-0.7

1974-75...-0.6

1983-84...-0.4

1984-85...-0.9

1985-86...-0.5

1995-96...-0.7

2005-06...-0.7

2008-09...-0.8

[okie333]

lol @ people arguing for a robust ST jet this winter

it is not happening

this is a major symptom of the ongoing pattern

given the severity of the drought what is currently a symptom will soon become one of many causes of a drought over most of the SE this winter (drought begets drought)

this kind of extreme dryness over TX right now is a major indicator that the STJ will be mostly absent this winter

What are your thoughts now on the topic of the STJ?