Page 18 of 57 < 1 2 ... 16 17 18 19 20 ... 56 57 >
Topic Options
#1252496 - 31/03/2014 15:23 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 2513
Loc: Buderim
NOAA appear to be using ARGO floats, and TAO is a network of tethered bouys.

One issue is the climatology to calculate an anomaly against - TAO goes back to mid 90s, and ARGO to mid 00s. The Pacific has been in a significantly cooler(La Nina) type mode since these systems were implemented. Older data comes from sources such as the XBT, which is similar to ARGO, but less extensive.

NOAA climatology is 1982-2004. TAO for the surface temperatures uses 1970-2000, but all I could find on the climatology for subsurface was that they use data going back as far as 1920. Not sure if this means something that is an average of the temp from 1920 to sometime recent, or just that in general the data they use to build a climatology from goes back that far.

I've noticed that often Kelvin Waves seem to dissappear in TAO data around the mid Pacific, and then reappear in the far east, whereas in NOAA the Kelvin Wave seems to maintain intensivity the whole way through. Not sure how either of the above two differences would explain this - if it was purely a baseline issue then I would expect Kelvin Waves in the mid Pacific to still be visible in both products, just with a different range of temperature change.

Top
#1252509 - 31/03/2014 17:18 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
CoastalStorm22 Offline
Weatherzone Addict

Registered: 10/07/2006
Posts: 2603
Loc: Lane Cove, Sydney, NSW
Thanks for information Mike, that does go some way to explaining the difference between the two.

Top
#1252600 - 01/04/2014 09:40 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 2513
Loc: Buderim
NCEP have their weekly update out. (link)

The heat content anomalies for central and east Pacific have risen to just over 1.5 degrees, which is as high or higher than at any time in any El Nino since 1990 other than 1997. In 1997 we reached just over 2 degrees, and at current rate of increase we could be there in 2 or three weeks. We should see fairly soon whether this will level off at or below 97 levels or go past it. (See pages 9-10)

Also interesting is the change in global SSTs over the last 4 weeks (page 8). As well as significant warming in the Nino regions, this also shows warming around Australia and in the Indian Ocean. The tropical SH ocean near the dateline has cooled back towards normal, and I believe it was the warm ocean in this area that contributed to the series of cyclones/low pressure systems that caused much of the recent burst of westerlies. The NH tropics in this region have warmed somewhat and monsoon activity is likely to switch to the NH soon.


Edited by Mike Hauber (01/04/2014 09:41)

Top
#1252607 - 01/04/2014 10:17 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4277
Loc: Brisbane
Very interesting report Mike.

What surprises me is that the majority of the forecasting ensembles are not forecasting a strong El Nino and the prediction is only a 50% chance of an El Nino through the SH winter. I'd be curious at this stage as to what they think will prevent one given the strength of the current kelvin wave.

The other thing I noticed through some of the data provided is that the 3 strongest El Nino events in 72/73, 82/83 and 97/98 were all followed by multi year La Ninas (even the 2010 event came close). 2 of those La Ninas were the strongest in the past half century.

This is interesting for SE QLD. The La Nina's of 74, 99 and 2011 all generated significant rainfall events for SE QLD. If we do get a relatively strong El Nino this summer I'd be wary of an equally strong and sustained La Nina in 2015 with a huge risk of flooding rains.

Top
#1252615 - 01/04/2014 11:34 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
_Johnno_ Offline
Weatherzone Addict

Registered: 08/11/2009
Posts: 1614
1982/83 strong El Nino was followed by neutral conditions
_________________________
Come and check out my weather page on facebook https://www.facebook.com/JohnsWeatherChannelJwc?ref=hl

Top
#1252621 - 01/04/2014 11:51 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4277
Loc: Brisbane
Not according to NCEP

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml

Certainly not a significant La Nina but a period where for over 2 years the ONI index remained below 0. Whilst there were no significant floods during this time there was a rainfall event in 1984 that put the Bremer into major flood.



Edited by Locke (01/04/2014 11:57)

Top
#1252625 - 01/04/2014 12:10 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
gazzatsv Offline
Weather Freak

Registered: 19/03/2011
Posts: 639
Loc: Townsville
Just looking at that link Locke, it is interesting to see that whilst we have had some La Nina's lately, they don't match longetivity of the ones leading out of 98, the 70's and 50's....wouldn't surprise me if we are due for a really long Nina.

Top
#1252632 - 01/04/2014 12:46 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4277
Loc: Brisbane
The ONI index was negative for a whole 2 years from June 2010 to May 2012 following the moderate/strong 2009 EL Nino event.

The 3 strongest El Nino events in 72/73, 82/83 and 97/98 were all followed by roughly 3 years worth of negative ONI readings (although 82/83 was a couple of months short of the 3 years).

I suspect in 2014 were likely to see an El Nino that is stronger than the 2009/10 event lasting until 2015 autumn and subsequently 2-3 years of below neutral conditions starting in the 2015 SH winter.

From what I can see the strength of the follow up La Nina seems to be to some extent determine by how early in the year the transition from EL Nino to La Nina occurs. In 1973 and 1998 the transition occurred in the first half of the year whilst in 1983 it occurred in the second half. In all cases the period of negative ONI readings was sustained.

Top
#1252683 - 01/04/2014 18:07 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Tempest Offline
Weatherzone Addict

Registered: 17/11/2001
Posts: 3568
The 83 transition definately occured in March of that year, physcally it did anyhow, we had Ash Weds in Feb, and then we had flooding rain in late March which signalled the end of the el-nino.

Top
#1252694 - 01/04/2014 19:01 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4277
Loc: Brisbane
On thinking further about our current situation the 72/73, 82/83 and 97/98 El Nino events all lasted approx 12-14 months.

If the current conditions do spawn a similarly strong El Nino its becoming more likely that a subsequent turn around to La Nina conditions would occur in the second half of 2015. This would more likely result in weaker La Nina event albeit still a sustained one.

Top
#1252784 - 02/04/2014 09:47 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4277
Loc: Brisbane
It looks like the equatorial cunter currents are really starting to strengthen now.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstanim.shtml

This would certainly add to the the likelihood of a strong EL Nino event.

I'm wondering if its the South Equatorial Countercurrent that finally comes in and stops the upwelling from the Humboldt. You can see the NECC has already reached the North American Coastline but the SECC hasn't yet reached the South American coast disrupting the Humboldt.

Top
#1252793 - 02/04/2014 10:45 Re: ENSO Discussion 2014 [Re: Mike Hauber]
CoastalStorm22 Offline
Weatherzone Addict

Registered: 10/07/2006
Posts: 2603
Loc: Lane Cove, Sydney, NSW
Originally Posted By: Mike Hauber
NOAA appear to be using ARGO floats, and TAO is a network of tethered bouys.

One issue is the climatology to calculate an anomaly against - TAO goes back to mid 90s, and ARGO to mid 00s. The Pacific has been in a significantly cooler(La Nina) type mode since these systems were implemented. Older data comes from sources such as the XBT, which is similar to ARGO, but less extensive.

NOAA climatology is 1982-2004. TAO for the surface temperatures uses 1970-2000, but all I could find on the climatology for subsurface was that they use data going back as far as 1920. Not sure if this means something that is an average of the temp from 1920 to sometime recent, or just that in general the data they use to build a climatology from goes back that far.

I've noticed that often Kelvin Waves seem to dissappear in TAO data around the mid Pacific, and then reappear in the far east, whereas in NOAA the Kelvin Wave seems to maintain intensivity the whole way through. Not sure how either of the above two differences would explain this - if it was purely a baseline issue then I would expect Kelvin Waves in the mid Pacific to still be visible in both products, just with a different range of temperature change.


Looks like they deployed an additional 41 ARGO floats along the equator in March.

http://www.argo.ucsd.edu/Equatorial_deployments.html

Top
#1252859 - 02/04/2014 17:57 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 17452
Loc: Wide Bay..Near the beach
That link is interesting reading CoastalStorm. Thanks for that.

Some may enjoy this part of it as much as I did.

http://www.argo.ucsd.edu/How_Argo_floats.html
_________________________
"Don't steal. The government hates competition."

Top
#1252861 - 02/04/2014 18:08 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 17452
Loc: Wide Bay..Near the beach
On current evidence a moderate/strong Nino has got to be a fair chance.




The thermocline is starting to flatten out also.
_________________________
"Don't steal. The government hates competition."

Top
#1252870 - 02/04/2014 20:04 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
CoastalStorm22 Offline
Weatherzone Addict

Registered: 10/07/2006
Posts: 2603
Loc: Lane Cove, Sydney, NSW
No question about that CF, question is how severe will its affects be? The way the SST's around OZ are heading at the moment it might not be so bad, especially if the IOD stays in the neutral range.

Top
#1252882 - 02/04/2014 22:11 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Kev in Bello Offline
Occasional Visitor

Registered: 23/09/2001
Posts: 5032
Loc: Bellingen NSW 2454
So a question - assuming the low in the CS does form into something decent, then hangs around for a while... Is that alone able to kick off a WWB?

Top
#1252893 - 02/04/2014 23:26 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Trispectrum Offline
Cloud Gazer

Registered: 25/02/2014
Posts: 12
A very interesting thread. I have also been following the following thread on a possible El Nino in 2014 at:
http://forum.arctic-sea-ice.net/index.php/topic,730.0.html.

There has been some comments on the possibility of a cyclone in the Western Equatorial Pacific that might impact the Philippines kicking of WWB in the next few days. They have also commented recently on the very large size of the EWK. This seems to match some of the recent discussion on this tread.

Top
#1252912 - 03/04/2014 09:31 Re: ENSO Discussion 2014 [Re: Kev in Bello]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 2513
Loc: Buderim
Originally Posted By: Bello Boy
So a question - assuming the low in the CS does form into something decent, then hangs around for a while... Is that alone able to kick off a WWB?


Its a bit of a chicken and egg thing - the westerlies help kick the cyclone off, which helps maintain the westerlies. There is currently a moderate area of westerlies along the equator which is helping to spin this thing up. This cyclone looks to be quite close to the equator, which certainly helps, however it is small in terms of overall circulation size. The overall westerly activity according to the latest GFS model run is restricted to a much smaller area than we have been seeing westerlies over much of the last two months. The forecast shows the current westerly activity weakening a little further over the next few days. If the cyclone moves south or west that reduces the westerly influence, if it moves east or north that increases it. Doesn't matter much whether it is a cyclone or low as it is only the outer edge of the circulation that affects the equatorial region.


Top
#1252920 - 03/04/2014 10:11 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4277
Loc: Brisbane
I'm actually prepared to call it now. It will be an El Nino and it will be a strong one.

The strengthening of the equatorial counter currents over the past week or so had been impressive to watch and a sure sign that a strong El Nino is on the way.

Whilst you can still see the effect of the upwelling from the Humboldt off the coast of South America I expect that the SECC will soon cause severe disruption and then the warm anomalies will be seen all the way to the South American coast.

Top
#1252923 - 03/04/2014 10:17 Re: ENSO Discussion 2014 [Re: bd bucketingdown]
snowbaby Offline
Weather Freak

Registered: 05/08/2009
Posts: 295
Loc: Albany, W.A
Fully enjoying this discussion as our winter approaches. Dont understand a lot about it though. Just one left field thing coming from yesterday’s earthquake - whether these underwater events contribute in anyway to the bigger picture dynamics in particular regions(like the South American coast) - perhaps as triggers? Just a thought...

Top
Page 18 of 57 < 1 2 ... 16 17 18 19 20 ... 56 57 >


Who's Online
8 registered (Timbuck, StormCapture, Lee@Hazo, Cheers, Warmfront, RC, 2 invisible), 81 Guests and 3 Spiders online.
Key: Admin, Global Mod, Mod
Today's Birthdays
caffeinated, Chaser_James, coffeeman, rhyso, Shear-iously
Forum Stats
29343 Members
32 Forums
23661 Topics
1458634 Posts

Max Online: 2925 @ 02/02/2011 22:23
Satellite Image