Update: it appears that the September values of the Tahiti-Darwin SOI (+25) and Klaus Wolter Multivariate ENSO Index (MEI) are at historical levels when compared to previous Septembers, with the SOI only showing a higher September value (+29.7) back in 1917!
From the Australian Bureau of Meteorology, the trace is now at a comparable level to the 2008 La Niña, though the onset is more rapid:
Issued on Wednesday 13 October
The La Niña in the Pacific remains a moderate to strong event. The Southern Oscillation Index (SOI) value of +25 for September was its highest monthly value since 1973 [Ryan Maue adds here: the September value of +25 is the highest value for that month since 1917, the only other time it has been exceeded according to the Tahiti-Darwin SOI data back to 1876], while central Pacific Ocean temperatures are comparable to those observed during previous moderate events, such as 2007 and 1998. Long-range models surveyed by the Bureau suggest that this La Niña will persist into at least early 2011.
ENSO indicators remain firmly at La Niña levels. The central Pacific Ocean is more than 1°C cooler than the long-term mean at the surface, while temperatures below the surface are up to 5°C cooler than normal. The SOI remains above +20, which places it in the top 5% of observed values. Although trade winds are stronger than normal over the western Pacific and cloudiness over the central and western Pacific continues to be suppressed, a strong Madden Julian Oscillation (MJO) may weaken some of these indicators over the coming fortnight.
La Niña periods are generally associated with above normal rainfall during the second half of the year across large parts of Australia, most notably eastern and northern regions. Night time temperatures are historically warmer than average and Tropical Cyclone occurrence for northern Australia is typically higher than normal during the cyclone season (November-April).
A negative IOD event is also underway in the Indian Ocean. Negative IOD events are typically associated with above average rainfall over large areas of southern Australia during spring. IOD events usually decay in the months of November and December with the onset of the Australian monsoon.
Click image to go to BOM page or see our WUWT ENSO/SST page here
h/t to Geoff Sharp
On the opposite side in the Arctic, there are also signs of cold winter on the way. There is a hot spot developing in the Labrador Sea due to release of heat into atmosphere from a brunch of Gulf Stream.
http://weather.unisys.com/surface/sst_anom.gif
This could move polar jet-stream further south than normal, implying colder winter for the North Atlantic areas.
“The central Pacific Ocean is more than 1°C cooler than the long-term mean at the surface, while temperatures below the surface are up to 5°C cooler than normal”
Is the 5C cooler typical for a La Nina of this degree?
Thanks in advance.
Brr. Snow expected in England next week – look out for london grinding to a halt in another October!
Some more bon mots from the Australian B.O.M.
They have just realized that there is such a thing as the U.H.I.
Hot Cities
David says:
October 14, 2010 at 2:42 am
“The central Pacific Ocean is more than 1°C cooler than the long-term mean at the surface, while temperatures below the surface are up to 5°C cooler than normal”
Is the 5C cooler typical for a La Nina of this degree?
Yes – I picked that up too. From the track of cold water around Bermuda where hurricane Igor passed by more than a month ago, it looks like the Atlantic hasn’t got any warm water below the surface either.
This could be investigated if NOAA would allow the ARGO data to be accessed. The ARGO teams seem to be unwilling to release details of the ocean temperatures. One wonders why this is.
Local meteorologists are telling us that the rains are set to begin in 10-14 days for California. We are wondering what kind of storms they will be given the colder Sea temps of La Nina.
They illustrated NINO3 region (5S-5N, 150W-90W) SST anomalies in the graph above. It’s a little east of the NINO3.4 region (5S-5N, 170W-120W) which is more commonly used. The NINO3.4 SST anomalies this year have been well below the levels of the 2007/08 La Nina since May/June:
http://i53.tinypic.com/sls9k8.jpg
For those who missed it a few days ago, here’s a link to the monthly SST update for September:
http://bobtisdale.blogspot.com/2010/10/september-2010-sst-anomaly-update.html
Anthony: Shouldn’t the headline read “2007 levels”? The La Niña that year straddled 2007/08. Similarly, this one will straddle 2010/11.
None of the BOM/world models were showing any predictions below 1.5° earlier this summer. Now they are all heading south. Good stuff these models, eh.
Les Francis says:
October 14, 2010 at 3:31 am
Some more bon mots from the Australian B.O.M.
They have just realized that there is such a thing as the U.H.I.
They are soooo passé. They make it sound like they have just discovered something wonderful. Scientist? more like idiots.
rbateman says:
October 14, 2010 at 4:26 am
Local meteorologists are telling us that the rains are set to begin in 10-14 days for California. We are wondering what kind of storms they will be given the colder Sea temps of La Nina.
In southern france we are desperate for some rain. 3 consequtive years of drought means my house has started to move again having been piled following the droughts of 2003, 2005, 2007-10.
Bob Tisdale
What are your thoughts on the 5°c, the overhang of global temps during this niña fall??
What we don’t seem to know yet exactly what drives these quasi-regular fluctuation in and above the tropical Pacific Ocean. Therefore, nor do we know for certain what relationship these events have with long-term weather. Contrary to some commentators’ beliefs (or prejudices), we cannot yet say whether the strengthening La Nina will affect the NH winter to make it colder as the previous La Nina didn’t cause warm conditions in UK and US. Must be some other confounding influence?
Pingo says:
October 14, 2010 at 3:07 am
Brr. Snow expected in England next week – look out for london grinding to a halt in another October!
That would be about 20 Oct. according to GFS. http://www.theweatheroutlook.com/twodata/datmdlout.aspx
Anthony: Shouldn’t the headline read “2007 levels”? The La Niña that year straddled 2007/08. Similarly, this one will straddle 2010/11.
vukcevic says:
October 14, 2010 at 2:10 am
“…a brunch of Gulf Stream.”
Low calorie cirtainly but a little salty for my taste.
Of course none of the models predicted this. They were all following the ‘El Nino hottest year on record’ meme.
I can’t hear the Com’ Games closing ceremony on the tele because of the rain on my tin roof – dams are full, tanks are full and ground is saturated.
That’s enough for this year Gaia, the wheat needs to ripen now…
Rivers are breaking their banks, major water catchment dams are spilling at over 4 metres over the wall.
Must be climate disruption… Better tax carbon dioxide because… we…
Oh I just give up…
It is after all the hottest year on record…
Not.
Hurt my leg last year when the PacNW had a nino winter, this year I’m goin’ Skiin’….
jackstraw says:
October 14, 2010 at 6:51 am
“When the rains come to California, then snows come to the Rockies. My snowmobiles are ready, the wood is stacked high, my phat skis are ready. I hope it is another epic powder year like it was the last La Nina.”
jackstraw, where are you in the Rockies? During the 2007/2008 La Niña many ski areas in Colorado had record snowfall. It was one of my best seasons ever in my 28 years of skiing. I’m praying for a repeat this season – my Fat-ypus D-Senders are ready.
Phil’s Dad, I did see spelling error, but once is up there it was too late, I was having a late breakfast at the time. It would be useful if one can edit minor errors while post is awaiting moderation.
I hope Phil is a good boy.
rbateman says:
October 14, 2010 at 4:26 am
Local meteorologists are telling us that the rains are set to begin in 10-14 days for California.
Is that unusual? Perhaps a little early? In any case, isn’t a La Niña winter expected to bring less rain to California?
I also wonder what the “local meteorologists” know. I don’t see that the NWS folks out of LOX are expecting much:
http://www.wrh.noaa.gov/lox/scripts/getprodplus.php?sid=lox&pil=afd&back=yes
vukcevic says: “Phil’s Dad, I did see spelling error, but once is up there it was too late…”
We all knew what you meant, Vuk. It’s not important.
Yes, but where’s the impact on the global anomally? Even Roy Spencer is scratching his head over that one.