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January 2016 Pattern Disco


Damage In Tolland

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How many Super Nino February's are there to compare to come up with a base state? Feb 1998 and Feb 1983?

How many Decembers are there???

 

Common sense would dictate that if you wish to expand the sample size, then include moderate el nino seasons, as well as low-end strong....which yields an identical composite.

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Everyone dry humped Cohen for the Kara Sea ridge. That goes bye-bye next week and was the reason why the AO goes negative. It goes near neutral at end of EPS.

The -AO looks completely tropospherically driven from the tropical convective forcing moving. I see no signs of a major SSW yet or a real big shift in the stratospheric vortex yet
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Oxymoron.

 

I'll take my chances with a -PNA not remaining prevalent throughout one of the strongest el nino seasons on record.

 

This was the first pulse of energy, and we no where near finished.

 

I understand Scott hates Cohen, but try to remain objective.

 

All I'm saying is that the Nino/-PNA combo is brutal for us. 

 

To be honest... I could care less about February and haven't given it much thought. I'm talking about the 1/10 pattern shift and its longevity. I haven't seen anything right now to make me think the AO reversal is suddenly going to save winter. The stratospheric PV is still strong and cold - not sure we're anywhere near a death blow even with a tropospheric disruption this week. 

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I'm gonna go with the idiot 45 day forecast on Accweather since it predicted December to a "T" almost a month out. They say its gonna get cold as we move from January into February. 

 

Not truly convinced of this, but whatever they use for their long range was spot on for December. Probably a toss up as to where it goes right now. 

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All I'm saying is that the Nino/-PNA combo is brutal for us. 

 

To be honest... I could care less about February and haven't given it much thought. I'm talking about the 1/10 pattern shift and its longevity. I haven't seen anything right now to make me think the AO reversal is suddenly going to save winter. The stratospheric PV is still strong and cold - not sure we're anywhere near a death blow even with a tropospheric disruption this week. 

Oh, sorry.

Yes, I could definitely see a mid month break....been saying that.

As far as the state of the vortex moving forward, I'll just say that your posts are a must-read for me, and I respect your input greatly....as well as Scott's.

We are just going to have to wait and see....no use arguing over an outcome that has yet to present itself.

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Oh, sorry.

Yes, I could definitely see a mid month break....been saying that.

As far as the state of the vortex moving forward, I'll just say that your posts are a must-read for me, and I respect your input greatly....as well as Scott's.

We are just going to have to wait and see....no use arguing over an outcome that has yet to present itself.

 

Well I'm definitely not an expert on the polar vortex or stratosphere. I sort of chuckled when I read on Twitter about the PV getting the death blow from the usual sources and Judah saying things were going according to plan - then I looked at the 10mb-50mb forecasts on GFS/Euro and I saw no real warming and no slow down to the polar night jet. 

Sure the troposphere could be the catalyst but we want to start seeing changes in the stratosphere before we think it's a permanent change. 

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Well I'm definitely not an expert on the polar vortex or stratosphere. I sort of chuckled when I read on Twitter about the PV getting the death blow from the usual sources and Judah saying things were going according to plan - then I looked at the 10mb-50mb forecasts on GFS/Euro and I saw no real warming and no slow down to the polar night jet. 

Sure the troposphere could be the catalyst but we want to start seeing changes in the stratosphere before we think it's a permanent change. 

Very fair statement.

Agree.

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Well I'm definitely not an expert on the polar vortex or stratosphere. I sort of chuckled when I read on Twitter about the PV getting the death blow from the usual sources and Judah saying things were going according to plan - then I looked at the 10mb-50mb forecasts on GFS/Euro and I saw no real warming and no slow down to the polar night jet. 

Sure the troposphere could be the catalyst but we want to start seeing changes in the stratosphere before we think it's a permanent change. 

 

Right. I don't hate Judah, but he is very misleading at times. The Kara ridge and -AO is all tropospheric driven at the moment. The NPAC warming is there, but if anything, the vortex tries to congeal a little more at the end of the ensemble runs. Maybe in Feb is gets all disorganized again, but I see no signs of a SSW. 

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It's not only the Kara Sea ridge, IMO. There's also significant perturbing of the stratospheric vortex / warmth on the Pacific side that will aid in pumping heights poleward, which allows the kara heights to bridge. Without the wave driving from the Pacific side, I doubt the AO would be progged at such a negative magnitude. Ozone is significantly increased on the Pacific side right now, which is suggestive of those changes.

 

The Pacific side is probably aided by both Stratosphere and troposphere. MJO forcing is at the dateline so that will do it, regardless of stratosphere. 

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Vortex intensification period will be over the beginning of the month. Zonal winds at 10hpa/65N are projected to weaken to approximately 50% of present intensity per the ensemble mean. There's isn't much question that the stratospheric vortex will be weakening significantly in the first half of January, and as I said, I wouldn't expect any official SSW until around the 3rd week of the month. We'll see what happens. But I disagree with those who think there aren't any significant changes occurring in the next couple of weeks. I expect that we'll see WAF peak in the 3rd week in response to the precursor pattern, which is tropospherically forced. We are finally seeing some better  wave 1/2 amplitudes forecasted, and think those should continue to improve in the coming weeks.

 

u_65N_10hpa_gefs.png

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If you look at past SSW events, often we will see a -AO in the tropospheric pattern preceding the SSW. So while the stratospheric vortex might not be destroyed/disturbed yet, I don't think seeing a -AO tropospheric pattern is an argument against further progress later on. I believe the 1958, 1966, and 1987 examples all show this.

 

Often doesn't mean always though...so it's possible we regress back to a +AO late Jan and early February...but it's impossible to say with any certainty right now. I would favor a -AO personally for February right now because it is very common in El Ninos...even strong ones. My hope is that is doesn't get ruined by a mammoth Aleutian low that becomes so big it engulfs the GOA too and then combines with a strong Greenland vortex...that would be how to turn the pattern crappy...even if the AO is negative. 1998 saw this.

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Vortex intensification period will be over the beginning of the month. Zonal winds at 10hpa/65N are projected to weaken to approximately 50% of present intensity per the ensemble mean. There's isn't much question that the stratospheric vortex will be weakening significantly in the first half of January, and as I said, I wouldn't expect any official SSW until around the 3rd week of the month. We'll see what happens. But I disagree with those who think there aren't any significant changes occurring in the next couple of weeks. I expect that we'll see WAF peak in the 3rd week in response to the precursor pattern, which is tropospherically forced. We are finally seeing some better  wave 1/2 amplitudes forecasted, and think those should continue to improve in the coming weeks.

 

u_65N_10hpa_gefs.png

 

This graph is misleading. When you look at the temperature/zonal wind anomalies on the GEFS/EPS across the Arctic you can see the PV remaining quite strong. There is some displacement from warming over the Bering Sea through Siberia but the PV itself is just moving a bit not really getting disrupted.

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If you look at past SSW events, often we will see a -AO in the tropospheric pattern preceding the SSW. So while the stratospheric vortex might not be destroyed/disturbed yet, I don't think seeing a -AO tropospheric pattern is an argument against further progress later on. I believe the 1958, 1966, and 1987 examples all show this.

 

Often doesn't mean always though...so it's possible we regress back to a +AO late Jan and early February...but it's impossible to say with any certainty right now. I would favor a -AO personally for February right now because it is very common in El Ninos...even strong ones. My hope is that is doesn't get ruined by a mammoth Aleutian low that becomes so big it engulfs the GOA too and then combines with a strong Greenland vortex...that would be how to turn the pattern crappy...even if the AO is negative.

 

I think what's important to note is that this blocking is really due to tropospheric reasons - the stratospheric PV is still stout.

 

Of course, as you mention, we could see some stratospheric fun later in the winter that could kickstart the -AO. 

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This graph is misleading. When you look at the temperature/zonal wind anomalies on the GEFS/EPS across the Arctic you can see the PV remaining quite strong. There is some displacement from warming over the Bering Sea through Siberia but the PV itself is just moving a bit not really getting disrupted.

 

 

I think what's important to note is that this blocking is really due to tropospheric reasons - the stratospheric PV is still stout.

 

Of course, as you mention, we could see some stratospheric fun later in the winter that could kickstart the -AO. 

 

Yes and yes. 

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