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Winter 2015-2016 speculation and discussion


AlaskaETC

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The key will be the Aleutian low of course...if we have it the size of a supernova expanding into the GOA, then it's another '97-'98. If we keep it west though and not so gigantic, then we'll have some decent airmasses where Atlanta isn't colder than Montreal.

 

The tropical forcing thus far has been west of the typical super ninos...and it's starting to get later in the autumn, so we should see it start to show signs of shifting much further east soon if it is going to. Still time to do so, but this hasn't acted like the others. We'll see if it ends up mattering or not.

 

Noob question: what role does tropical forcing have in an El Nino? I don't know much about that topic.

 

Also, if it somehow doesn't shift to the east, would that be a good sign for winter?

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Noob question: what role does tropical forcing have in an El Nino? I don't know much about that topic.

 

Also, if it somehow doesn't shift to the east, would that be a good sign for winter?

 

 

ENSO as a whole is a coupled Ocean-Atmospheric process...tropical forcing can help evolve the ENSO event initially, and then there can be a feedback mechanism. As ENSO becomes more east-based, the warm SSTs can help deliver more convection further east which sustains the subsequent waves further east, and this in turn causes ENSO to become even more east-based with strong downwelling kelvin waves making it further east. This is why during stronger ENSO events (that are typically more east based), we see the tropical forcing set up well east of the dateline....the warmer water further east helps sustain it.

 

This event has had the forcing fail to materialize further east thus far. There have been attempts by the models to do so, but they usually fizzle as we get closer. We haven't had the very strong feedback mechanism that often occurs...so this event is becoming more of a basin-wide event rather than a strongly east based event that years like 1982 and 1997 became.

 

There is still time for it to change, but it's getting pretty deep into autumn. Of course, even if we get the forcing to stay west through the next month, there are still things that could screw up the winter. A couple ill-timed MJO waves can always be a pain or stratospheric troubles in the arctic that tug the Aleutian low northward can be issues. But so far, I think a fear of 1997-1998 should be kept a bit lower than maybe some have expressed during the last month.

 

But all things equal, yes, keeping the forcing from spreading east would be a good sign.

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ENSO as a whole is a coupled Ocean-Atmospheric process...tropical forcing can help evolve the ENSO event initially, and then there can be a feedback mechanism. As ENSO becomes more east-based, the warm SSTs can help deliver more convection further east which sustains the subsequent waves further east, and this in turn causes ENSO to become even more east-based with strong downwelling kelvin waves making it further east. This is why during stronger ENSO events (that are typically more east based), we see the tropical forcing set up well east of the dateline....the warmer water further east helps sustain it.

 

This event has had the forcing fail to materialize further east thus far. There have been attempts by the models to do so, but they usually fizzle as we get closer. We haven't had the very strong feedback mechanism that often occurs...so this event is becoming more of a basin-wide event rather than a strongly east based event that years like 1982 and 1997 became.

 

There is still time for it to change, but it's getting pretty deep into autumn. Of course, even if we get the forcing to stay west through the next month, there are still things that could screw up the winter. A couple ill-timed MJO waves can always be a pain or stratospheric troubles in the arctic that tug the Aleutian low northward can be issues. But so far, I think a fear of 1997-1998 should be kept a bit lower than maybe some have expressed during the last month.

 

But all things equal, yes, keeping the forcing from spreading east would be a good sign.

 

Thanks for the thoughtful response, that really helped.

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Yet I can't stop fearing suppression. Otoh, if there is some suppression, it could be good by keeping us far enough north of the surface low pressure.

I don't fear suppression in a strong el nino, but I'm sure there could be a first for anything.......2010 was more moderate.

Nor do I feel the forcing will resemble '97 at all, but regardless, I have a feeling that we are about to experience four months inside of a meteorological classroom.

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The key will be the Aleutian low of course...if we have it the size of a supernova expanding into the GOA, then it's another '97-'98. If we keep it west though and not so gigantic, then we'll have some decent airmasses where Atlanta isn't colder than Montreal.

 

The tropical forcing thus far has been west of the typical super ninos...and it's starting to get later in the autumn, so we should see it start to show signs of shifting much further east soon if it is going to. Still time to do so, but this hasn't acted like the others. We'll see if it ends up mattering or not.

I was thinking while running composites for my latest blog update....it almost seems as though the size of the GOA low was more important than precise placement...the "good" el nino years didn't feature lows very geographically far from the ratter years; however the latter had much, much larger lows.

 

Size matters... ; )

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I was thinking while running composites for my latest blog update....it almost seems as though the size of the GOA low was more important than precise placement...the "good" el nino years didn't feature lows very geographically far from the ratter years; however the latter had much, much larger lows.

 

Size matters... ; )

 

I think the PDO (assuming it stays hugely positive- it was again in Sep) might keep the low far enough west that it doesn't piss in our cereal, as it could force a neutral/neg EPO..the PDO/EPO correlation isn't rock solid like the PDO/PNA correlation, but it is there, especially in a strong +PDO.....40-41 was a strong nino for its time..and even using modern SST's as a base, it was pretty damn strong....probably stronger than any of the ones in the 50s/60s....And it had an obscene +PDO....Even though the low was a monstrosity, it didn't orient itself in a way that totally screwed us...It was a whatever winter here...warm dec/jan, cool/cold Feb/Mar.....average snow...but it could have been a mess...BTW -I'm only using this to make a point about the PAC...Personally, I do NOT expect the Atlantic to look anything like that..but even with a crappy Atlantic, I don't think that winter is 97-98

 

 

post-66-0-98354400-1445152105_thumb.png

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I think the PDO (assuming it stays hugely positive- it was again in Sep) might keep the low far enough west that it doesn't piss in our cereal, as it could force a neutral/neg EPO..the PDO/EPO correlation isn't rock solid like the PDO/PNA correlation, but it is there, especially in a strong +PDO.....40-41 was a strong nino for its time..and even using modern SST's as a base, it was pretty damn strong....probably stronger than any of the ones in the 50s/60s....And it had an obscene +PDO....Even though the low was a monstrosity, it didn't orient itself in a way that totally screwed us...It was a whatever winter here...warm dec/jan, cool/cold Feb/Mar.....average snow...but it could have been a mess...BTW -I'm only using this to make a point about the PAC...Personally, I do NOT expect the Atlantic to look anything like that..but even with a crappy Atlantic, I don't think that winter is 97-98

 

 

attachicon.gif4041.png

Looks like greenland block was oversurpressing that year negative anomalies are too far southeast.

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Looks like the blob is giving in a bit lately via GOA low.

 

Giw9bry.png

 

 

The low is not where we want it....We want it over the aleutians in October....Same thing happened last winter and everyone bit because of Cohen....I'm not saying it is the only factor, but It certainly gives me great pause when considering the AO/NAO...

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The low is not where we want it....We want it over the aleutians in October....Same thing happened last winter and everyone bit because of Cohen....I'm not saying it is the only factor, but It certainly gives me great pause when considering the AO/NAO...

Not my forte but last week's anoms def not the greatest. Does seem to be a recurring theme going forward too tho it's not necessarily super well established.

 

GFIFzIG.gif

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That location is not as bad as I thought over the last week.....usually you want an aleutian low in Oct for a winter -AO/NAO..

Can we get the same cold air supply that we had last winter (the same setup) during a Nino?

 

Is it possible to have the same -EPO and an active southern stream?  If so, sign me up.

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Can we get the same cold air supply that we had last winter (the same setup) during a Nino?

 

Is it possible to have the same -EPO and an active southern stream?  If so, sign me up.

 

Yes...see 2002-2003 winter.

 

jp_Rrc_Gdi_Zq.png

 

 

 

This would be hard to repeat though...that is about as good as you can get in the N PAC.

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That location is not as bad as I thought over the last week.....usually you want an aleutian low in Oct for a winter -AO/NAO..

 

If the ensemble means over the next 15 days are at least partially correct then the h5 mean for Oct would look pretty decent overall. The progs are for persistent higher heights in the epo region even with some undercutting of the +pna. While it would be nice to see the aleutian low further west, the probable overall look for the month certainly doesn't look anything like the bad big nino's. 

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Yes...see 2002-2003 winter.

 

 

 

 

 

This would be hard to repeat though...that is about as good as you can get in the N PAC.

 

02-03 was a pretty special year with the progression and timing. Even when we lost the -ao/nao in Feb, the -epo raged and we also benefited from a well placed Scandinavian block to put the squeeze on and keep a favorable storm track going even with no traditional blocking in the ao/nao domain.

 

 

post-2035-0-57743700-1445277791_thumb.jp

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This years enso numbers are projected quite a bit higher.  Does that increase/decrease the chances of getting a good setup like that?

 

From the very limited set of +enso years, it seems more likely for the epo to favor a +state. I don't read too much into it though. Not enough history to really bank on anything at long leads. 

 

Strong enso's are tough to figure out either way. Numerical indices don't really tell the whole story. 97-98 looks good on paper...heh...

 

 

 

DJF 57-58

 

post-2035-0-15925300-1445277949_thumb.jp

 

 

DJF 65-66

 

post-2035-0-82588300-1445277978_thumb.jp

 

 

DJF 72-73

 

post-2035-0-76423800-1445277995_thumb.jp

 

 

DJF 82-83

 

post-2035-0-17856800-1445278016_thumb.jp

 

 

DJF 97-98

 

post-2035-0-60766700-1445278035_thumb.jp

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Another step towards winter:

 

 

 

000
NOUS41 KLWX 191931
PNSLWX
DCZ001-MDZ003>006-011-013-014-016>018-503>508-VAZ028-030-031-
037>040-050>057-501-502-505-506-WVZ051>053-200400-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
331 PM EDT MON OCT 19 2015

...GROWING SEASON HAS ENDED FOR THE DISTRICT OF COLUMBIA...ALL OF
MARYLAND WEST OF THE CHESAPEAKE BAY...NORTHERN VIRGINIA...AND
EASTERN WEST VIRGINIA...

A FREEZE OCCURRED THIS MORNING IN THE MAJORITY OF THE NATIONAL
WEATHER SERVICE BALTIMORE/WASHINGTON OFFICE'S AREA OF
RESPONSIBILITY. WHILE A FEW LOCALES DID NOT REACH FREEZING...SUCH
AS DOWNTOWN WASHINGTON...DOWNTOWN BALTIMORE...AND THE CHESAPEAKE
BAY SHORE...THESE AREAS COMPRISE A SMALL MINORITY OF THE REGION.

THEREFORE...THE GROWING SEASON FOR SENSITIVE VEGETATION IS NOW
CONSIDERED AT AN END FOR OUR ENTIRE FORECAST AREA. AS A
RESULT...THE NATIONAL WEATHER SERVICE WILL NOT BE ISSUING FROST
OR FREEZE PRODUCTS UNTIL THE SEASON RESUMES IN SPRING 2016.

$

RCM
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Don't want to over rely on this indicator, but we know OPI is a thing...We could use some improvement in the location and perhaps strength of the NPAC low over the next 2 weeks...note...the composite is without respect to ENSO..I added in October 2014 as well...that location FWIW didn't help us obviously, though Judah Cohen has decided post mortem that EPO and AO are the same thing

 

 - I'm using NAO and probably should be using AO...maybe later..similar result

 

Massive -NAO JFM

 

post-66-0-15665800-1445284364_thumb.png

 

 

Those Octobers

 

post-66-0-99424900-1445284388_thumb.png

 

October 2015 so far

 

post-66-0-23407200-1445284406_thumb.gif

 

 

October 2014

 

post-66-0-26900900-1445284591_thumb.png

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