[mark]

Not sure if this is the right place for this but Grant can move it if he likes.



El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 23 May was +5. Contributing pressure anomalies were -0.3 hPa at Darwin and +0.5 hPa at Tahiti. After reaching +16 during April, the SOI has returned to more neutral values, consistent with ocean indicators. The monthly SOI for April was +15, and the 5-month running mean [centred on February] was -5.

Neutral conditions continue in the Pacific. The Pacific Ocean sea surface temperature [SST] pattern continues to cool in the equatorial regions, with all the major El Niño - Southern Oscillation [ENSO] indicators suggesting neutral conditions. The sub-surface temperature pattern has shown a large amount of cooling over the past 5 months, with almost the entire equatorial Pacific Ocean now being below average, and a large area east of the dateline reaching 2 to 4 degrees below normal. The tropical Indian Ocean and Maritime Continent region continue to have warmer than normal SSTs. The majority of climate model predictions suggest the tropical Pacific will continue to cool during the coming months, with the possible development of La Niña conditions towards September / October. It should be noted however, that model predictions at this time of year are generally less reliable than at other times of the year.

http://www.bom.gov.a.../tropnote.shtml

[Suezy]

Very good report Mark - does that mean that going from an El Niño to a La Niña mean that we are more likely to get snow this winter. It was reported on the Forum by someone that they did not know where or had not heard that being in an El Niño where snow would follow in the winter. So by being in a situation now we could get quite good falls of snow this year and with the Pacific being 2 to 4 deg below normal. Not very knowledgeable here as far as this is concerned but now only surmising.

[mark]

As the La Niña develops later this year we will see wetter weather here in Canterbury as for snow we should alest have 1 day of snow this year.I have record snow at lest once every year for the last 4 years.

[TokWW]

I think that instead of sub tropical lows bulldozing the blocking Highs apart and giving us moist nor-easters; now with cooler seas there, the southern mix of Lows > sou-westers from the southern Tasman sweeping up cold fronts and snow showers to the SI can predominate. (And colder temps to the NI as per snow and Winter). Perhaps I am generalising and what I said is typical of Winter anyway, but...

Can someone else educate us please? :icon_mrgreen:

This post has been edited by TokWW: 26 May 2010 - 06:18 PM

[mark]

Weekly Tropical Climate Note


at 1312 CST Tuesday 25 May 2010

El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 23 May was +5. Contributing pressure anomalies were -0.3 hPa at Darwin and +0.5 hPa at Tahiti. After reaching +16 during April, the SOI has returned to more neutral values, consistent with ocean indicators. The monthly SOI for April was +15, and the 5-month running mean [centred on February] was -5.

Neutral conditions continue in the Pacific. The Pacific Ocean sea surface temperature [SST] pattern continues to cool in the equatorial regions, with all the major El Niño - Southern Oscillation [ENSO] indicators suggesting neutral conditions. The sub-surface temperature pattern has shown a large amount of cooling over the past 5 months, with almost the entire equatorial Pacific Ocean now being below average, and a large area east of the dateline reaching 2 to 4 degrees below normal. The tropical Indian Ocean and Maritime Continent region continue to have warmer than normal SSTs. The majority of climate model predictions suggest the tropical Pacific will continue to cool during the coming months, with the possible development of La Niña conditions towards September / October. It should be noted however, that model predictions at this time of year are generally less reliable than at other times of the year.

[mark]

THIS is the one for last week.

Weekly Tropical Climate Note

at 1300 CST Tuesday 1 June 2010

El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 30 May was +10. Contributing pressure anomalies were -0.8 hPa at Darwin and +0.4 hPa at Tahiti. The monthly SOI for April was +15, and the 5-month running mean [centred on February] was -5.

Neutral conditions continue in the Pacific. The Pacific Ocean sea surface temperature [SST] pattern continues to cool in the equatorial regions, with all the major El Niño - Southern Oscillation [ENSO] indicators suggesting neutral conditions. The sub-surface temperature pattern has shown a large amount of cooling over the past 5 months, with almost the entire equatorial Pacific Ocean now being below average, and a large area east of the dateline reaching 2 to 4 degrees below normal. The tropical Indian Ocean and Maritime Continent region continue to have warmer than normal SSTs. The majority of climate model predictions suggest the tropical Pacific will continue to cool during the coming months, with the possible development of La Niña conditions towards September / October. It should be noted that correctly predicting transitional periods of ENSO is more difficult than predicting the continuation or decline of El Niño or La Niña events.

[mark]

http://bobtisdale.bl...aly-update.html
 2h2p3xy.png (34.91K)
Number of downloads: 7

[mark]

Weekly Tropical Climate Note

at 1320 CST Tuesday 8 June 2010

El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 6 June was +9. Contributing pressure anomalies were -0.5 hPa at Darwin and +0.6 hPa at Tahiti. The monthly SOI for May was +10, and the 5-month running mean [centred on March] was -2.
Neutral conditions continue in the Pacific. The Pacific Ocean sea surface temperature [SST] pattern continues to cool in the equatorial regions, with all the major El Niño - Southern Oscillation [ENSO] indicators suggesting neutral conditions. The sub-surface temperature pattern has shown a large amount of cooling over the past 6 months, with almost the entire equatorial Pacific Ocean now being below average, and a large area east of the dateline reaching 2 to 4 degrees below normal. The tropical Indian Ocean and Maritime Continent region continue to have warmer than normal SSTs. The majority of climate model predictions suggest the tropical Pacific will continue to cool during the coming months, with the possible development of La Niña conditions towards September / October. It should be noted that correctly predicting transitional periods of ENSO is more difficult than predicting the continuation or decline of El Niño or La Niña events.

[Suezy]

Very very interesting Mark - from a real layperson.

[mark]

Weekly Tropical Climate Note


at 1600 CST Tuesday 15 June 2010

El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 13 June was +7. Contributing pressure anomalies were +0.2 hPa at Darwin and +1.2 hPa at Tahiti. The monthly SOI for May was +10, and the 5-month running mean [centred on March] was -2.

Neutral ENSO conditions persist in the equatorial Pacific. While sea surface temperatures [SST] continue to cool, all major El Niño - Southern Oscillation [ENSO] indicators show a neutral state. Sub-surface temperatures have shown a large amount of cooling over the past 6 months, with almost the entire equatorial Pacific Ocean now below average and large areas east of the dateline up to 2 - 4 °C below normal. The tropical Indian Ocean and Maritime Continent region continue to have warmer than normal SST. The majority of climate model predictions suggest the eastern Pacific will continue to cool during the coming months, possibly below La Niña thresholds by the southern hemisphere spring.

http://www.bom.gov.a.../tropnote.shtml

[Grant]

I know absolutely nothing about La Nina, so this is an interesting topic to follow weekly. Thanks

[mark]

Weekly Tropical Climate Note


at 1123 CST Tuesday 22 June 2010

El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 20 June was +5. Contributing pressure anomalies were +0.8 hPa at Darwin and +1.5 hPa at Tahiti. The monthly SOI for May was +10, and the 5-month running mean [centred on March] was -2.

Sea surface temperatures [SST] continue to cool in the central and eastern equatorial Pacific, while the tropical eastern Indian Ocean and Maritime Continent region exhibit warmer than normal SSTs. Pacific ocean sub-surface temperatures have also cooled, with significant areas below the surface displaying temperatures 2 - 4 °C below normal. Correspondingly, the easterly trade winds west of the dateline are stronger than normal and convection in the equatorial Pacific is reduced. The majority of climate models surveyed by the Bureau suggest the central and eastern tropical Pacific will continue to cool during the coming months.

http://www.bom.gov.a.../tropnote.shtml

[Suezy]

Thanks Mark as very interested in this.

[mark]

 AMSRE-SST-Nino34-change-rate-thru-June-17-2010.gif (22.84K)
Number of downloads: 8

http://www.drroyspen...e-their-plunge/

[mark]

La Nina to drop buckets of water. again
By Malcolm Holland From: The Daily Telegraph June 24, 2010 12:00AM

The Bureau of Meteorology believes a La Nina, Spanish for The Little Girl, is more likely than not to form before the end of winter.

La Ninas, a little understood weather phenomenon in which a massive pool of warmer than normal water builds off northeastern Australia in the Coral Sea, can bring a massive increase in rainfall and more cyclones.

Scientists are still not exactly sure what triggers La Ninas, but every three to seven years or so the differences of barometric pressure between the eastern and western sides of the Pacific increases.

[Suezy]

mark, on 23 June 2010 - 05:53 PM, said:

AMSRE-SST-Nino34-change-rate-thru-June-17-2010.gif

http://www.drroyspen...e-their-plunge/

Most interesting Mark and also the article on the lack of sunspots. Amazing the technology available now and research being done.

[mark]

Thank Suezy iv been interested this for years and i hope more will get interested to. We wouldnt have weather with out the Sun.

This post has been edited by mark: 29 June 2010 - 07:58 PM

[Suezy]

That is for real Mark - any other articles you get on this would be appreciated too. Also the La Nina reports as they are well below the 2007 -2008 results at this stage.

This post has been edited by Suezy: 29 June 2010 - 10:07 PM

[mark]

Weekly Tropical Climate Note


at 1211 CST Tuesday 29 June 2010

El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 27 June was +2. Contributing pressure anomalies were +0.9 hPa at Darwin and +1.1 hPa at Tahiti. The monthly SOI for May was +10, and the 5-month running mean [centred on March] was -2.

Sea surface temperatures [SST] continue to cool across the equatorial Pacific, while the tropical Indian Ocean and Maritime Continent region exhibit warmer than normal SSTs. Pacific ocean sub-surface temperatures remain cooler than normal, with some areas now more than 4 °C below average. Additionally, easterly trade winds in the western Pacific have strengthened, while convection near the dateline has reduced. All of these indicators, together with an SOI that has remained positive since April, are consistent with the developing stages of a La Niña event. Supporting this, the majority of climate models surveyed by the Bureau suggest the central and eastern tropical Pacific will continue to cool in the coming months.
http://www.bom.gov.a.../tropnote.shtml

This post has been edited by mark: 30 June 2010 - 06:13 AM

[mark]

Weekly Tropical Climate Note


at 1319 CST Tuesday 6 July 2010

El Nino-Southern Oscillation Update
The 30-day Southern Oscillation Index [SOI] to 4 July was +3. Contributing pressure anomalies were +0.5 hPa at Darwin and +0.9 hPa at Tahiti. The monthly SOI for June was +2, and the 5-month running mean [centred on April] was zero.

Sea surface temperatures [SST] have continued to cool across the equatorial Pacific, while the tropical Indian Ocean and Maritime Continent region exhibit warmer than normal SSTs. Pacific Ocean sub-surface temperatures remain cooler than normal, with some areas now more than 4 °C below average. Additionally, easterly trade winds in the western Pacific have strengthened, while convection near the dateline has greatly reduced. All of these indicators, together with an SOI that has remained positive since April, are consistent with the developing stages of a La Niña event. Supporting this, the majority of climate models surveyed by the Bureau suggest the central and eastern tropical Pacific will continue to cool in the coming months.