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Weak La Nina Winter


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24 minutes ago, StormchaserChuck said:

So we're in Moderate Nina now. ONI is 3-months, but that will likely peak at Weak because the SSTs just outside of equator are so warm. Strong Nina effects are being felt...

In what way?  The jet steam is currently in a mode globally where the subtropical jet is stronger than normal and the polar jet is a little weaker than normal.  A +AO regime would be favored in a strong Nina.  We don't have that.  Also, a strong SE ridge would be favored.  Don't have that either.  We have an upcoming -AAM drop, but don't see that as unusual unless AAM was strongly negative for a substantial amount of time

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54 minutes ago, 40/70 Benchmark said:

La nina is weak and will remain so.

Period.

The MEI is weak,too....anything else is voodoo.

If the current trade wind pattern continues it will most definitely not remain weak. As Andy noted above, it already is moderate per weekly basis and I see nothing in the near future to change that. Just continuation of cooling especially in the in the 3, 3.4, and 4 ENSO regions.

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There is a guy on another forum arguing this is 1999-00 with a one month delay - if that is the case, mother of all torches is coming December? I mean, to be fair the CFS kind of does show that, and I wouldn't be surprised if it ends up warm on the coasts in December, but I think nationally its a big stretch to get this: 

Jyqg1Py.png

I'm assuming he/she hasn't looked at the magnitudes of the anomalies for that year? Very hard to imagine the Upper Midwest being that hot in December in this pattern (for me at least). If it was to happen, I'd imagine it in January or February honestly, at 1/4 of the magnitude above.

The ONI peak is probably sometime between now and January, as NOAA has noted (see the 60-year ONI thread) the actual SSTs have been colder in Jan-Mar in 1986-2015 v. recent previous 30 year means due to later peaking events. My view is the peak is around Jan 1, later than the ~Nov 1 peak last year. At some point I think the warmth around 10N is going to try to drain into Nino 1.2 or Nino 3 and that will kill the event. Nino 1.2 on Tropical Tidbits already may be past its peak - was briefly down to -2.0C and now its up quite a bit. That's been where all the cold subsurface water has been up-welling before heading west.

nino12.png

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5 hours ago, Stebo said:

If the current trade wind pattern continues it will most definitely not remain weak. As Andy noted above, it already is moderate per weekly basis and I see nothing in the near future to change that. Just continuation of cooling especially in the in the 3, 3.4, and 4 ENSO regions.

Per weekly isn't how we determine intensity.

 

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6 hours ago, andyhb said:

Most recent CPC weekly SSTA in Nino 3.4 was -1.1˚C, so over a short timespan this already invalidates this claim, but sure.

this seems like an odd response Andy.  4 out of the 5 the weak la ninas since 1990 had a few weeks or even several weeks reach "moderate" levels on the weekly data.  That doesn't make a moderate nina.  I don't really know what Chuck is talking about.  It's not even official a la nina yet. 

 

 

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3 hours ago, OSUmetstud said:

this seems like an odd response Andy.  4 out of the 5 the weak la ninas since 1990 had a few weeks or even several weeks reach "moderate" levels on the weekly data.  That doesn't make a moderate nina.  I don't really know what Chuck is talking about.  It's not even official a la nina yet. 

 

 

One final note....the Sept/Oct bimonthly MEI value was -.551, so these urban legends about la nina being stronger than we think are unfounded.

Perhaps we see a big spike in the OCT/Nov, MEI, and if so, then we reevaluate.

 

I would argue that this particular cold ENSO event may just need to peak at moderate weekly levels in order to guarantee ultimate la nina designation, given the lethargic rate of development coupled with the anticipated late winter/early spring weakening.

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24 minutes ago, CoastalWx said:

And the atmospheric response hasn't exactly screamed Nina lately either. 

It did in September and October. You guys are looking too short sighted with the cool down this month, which is/was still possible in a La Nina. Novembers are more variable than any other month preceding a La Nina winter.

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4 hours ago, 40/70 Benchmark said:

Per weekly isn't how we determine intensity.

 

Didn't say we did, but it is an area to look at to monitor trends in the ENSO especially when you look at everything else around it, trade winds, subsurface cooling, MJO progression. It isn't an irrelevant piece to the puzzle that is for sure.

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35 minutes ago, Stebo said:

It did in September and October. You guys are looking too short sighted with the cool down this month, which is/was still possible in a La Nina. Novembers are more variable than any other month preceding a La Nina winter.

I mentioned lately. It definitely did in Sept and Oct. My point is although the SSTs are the metric everyone goes by, the atmosphere doesn't always follow the specific analogs. 

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Just now, CoastalWx said:

I mentioned lately. It definitely did in Sept and Oct. My point is although the SSTs are the metric everyone goes by, the atmosphere doesn't always follow the specific analogs. 

Oh no I do agree there, I will say lately it hasn't but looking mid to long range with the AAM drop things things should have a more La Nina look. I just hope people didn't bite too hard on this cool period thinking this was going to lock in for the rest of winter.

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1 minute ago, Stebo said:

Oh no I do agree there, I will say lately it hasn't but looking mid to long range with the AAM drop things things should have a more La Nina look. I just hope people didn't bite too hard on this cool period thinking this was going to lock in for the rest of winter.

I thought like 10 days ago December would snap back based on AAM/MJO etc and hasn't happened yet. I was thinking more maybe after mid month? Clearly some other tropospheric forcings are overwhelming the low frequncy Nina signal for now anyways. 

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Just now, CoastalWx said:

I thought like 10 days ago December would snap back based on AAM/MJO etc and hasn't happened yet. I was thinking more maybe after mid month? Clearly some other tropospheric forcings are overwhelming the low frequncy Nina signal for now anyways. 

My thought is around Dec 20th give or take a few days.

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47 minutes ago, Stebo said:

Didn't say we did, but it is an area to look at to monitor trends in the ENSO especially when you look at everything else around it, trade winds, subsurface cooling, MJO progression. It isn't an irrelevant piece to the puzzle that is for sure.

No, it isn't,  but I don't think a -1.1 reading is very significant.

 

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8 hours ago, OSUmetstud said:

this seems like an odd response Andy.  4 out of the 5 the weak la ninas since 1990 had a few weeks or even several weeks reach "moderate" levels on the weekly data.  That doesn't make a moderate nina.  I don't really know what Chuck is talking about.  It's not even official a la nina yet. 

Idk, maybe I'm just tired of his arrogance. This kept happening in the tropical threads as well.

Believe me, I'm no defender of Chuck.

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7 hours ago, andyhb said:

Idk, maybe I'm just tired of his arrogance. This kept happening in the tropical threads as well.

Believe me, I'm no defender of Chuck.

So you're compromising your objectivity because you don't like me?

Sorry, I just don't see where he's coming from since the MEI is also weak. I already said, maybe that rises alot this month....we'll see.

I'm huge fan of Chuck, dude....not trying to impugn his efforts,  but this one is lost on me.

 

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11 hours ago, Stebo said:

At a weekly standpoint no, but if the pattern continues, I don't see anything to warm SSTs anytime soon. At what point does it become significant then?

It's def. intensifying...we'll see.

I'm no ENSO expert...believe me. 

I'll be the first to admit if I'm wrong.

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3 hours ago, 40/70 Benchmark said:

So you're compromising your objectivity because you don't like me?

Sorry, I just don't see where he's coming from since the MEI is also weak. I already said, maybe that rises alot this month....we'll see.

I'm huge fan of Chuck, dude....not trying to impugn his efforts,  but this one is lost on me.

I personally think it's unwise to declare "the Nina will stay weak, period" before the typical December/January peaks in magnitude. Last year, that may have been a more sound notion.

Also I get the feeling that some of the people counting on an east-based La Nina through winter may have been a bit premature. This east-west propagation that we might be seeing the initial phases of now is fairly common in Nina events.

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3 hours ago, andyhb said:

I personally think it's unwise to declare "the Nina will stay weak, period" before the typical December/January peaks in magnitude. Last year, that may have been a more sound notion.

Also I get the feeling that some of the people counting on an east-based La Nina through winter may have been a bit premature. This east-west propagation that we might be seeing the initial phases of now is fairly common in Nina events.

Ok, fair enough.

I didn't mean to be dismissive...my bad.

At which point do we begin to consider the window for structural changes within the ENSO to manifest themselves into the winter regime to be closed?

Kind of late in thegame...is there not a lag?

Honest question-

 

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I went with "east-central" for the La Nina in my analogs (115-135W) because the biggest anomalies should gradually migrate out of Nina 1.2 to Nino 3/Nino 3.4. But the super cold Nino 1.2 now is consistent at least with a colder US pattern for December at least. Not sure the type of Nina matters too much, this event will be different from last year without Nino 1.2/the PDO interfering massively with precipitation patterns.

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9 hours ago, 40/70 Benchmark said:

Ok, fair enough.

I didn't mean to be dismissive...my bad.

At which point do we begin to consider the window for structural changes within the ENSO to manifest themselves into the winter regime to be closed?

Kind of late in thegame...is there not a lag?

Honest question-

There is a lag, but any substantial changes that occur in Dec or Jan are liable to alter forcing for at least a short period of time during the winter.

Another reason we are seeing trades continue this time as opposed to being interrupted is the relatively inactive MJO compared to earlier in the month.

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Shoot guys, Nino 3.4 is -1.1 and Winter hasn't even begun! They often keep strengthening until the middle of Winter. I think the pattern effects are probably immediate. +SSTAs so close north is the biggest dampening problem(the globe is warm right now), but overall probably sustainable Moderate going forward, subsurface is strong. Can we do less aesthetic

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4 hours ago, andyhb said:

There is a lag, but any substantial changes that occur in Dec or Jan are liable to alter forcing for at least a short period of time during the winter.

Another reason we are seeing trades continue this time as opposed to being interrupted is the relatively inactive MJO compared to earlier in the month.

 

That's very, very weak...barely out of cab. Not much of a player, surprised Ben would even tweet about it. He must be really bored!

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