El Nino 2015/16

[RWood]

Wellington has had 159 hrs sun to 20th and negligible rain, best October in years so far.

[TonyT]

Probably OT, but:

I find it interesting how people personalise the weather as "good" or "bad". I suppose a lifetime of weather watching has knocked that probably innate and natural temptation to editorialise the weather out of me, but for me the best weather is that which is closest to the long term normal for a place or a time of year. The further it gets away from the "usual" - either persistently rainy and cold or persistently sunny and warm - the less I like it.

[RWood]

Probably OT, but:

I find it interesting how people personalise the weather as "good" or "bad". I suppose a lifetime of weather watching has knocked that probably innate and natural temptation to editorialise the weather out of me, but for me the best weather is that which is closest to the long term normal for a place or a time of year. The further it gets away from the "usual" - either persistently rainy and cold or persistently sunny and warm - the less I like it.

Since in an alternative world I would be living in a Mediterranean or desert-like climate it's natural that I celebrate weather that is drier and sunnier than normal, and would do so no matter where I lived in NZ. A couple of weeks in the SW of the US plus an unusually warm San Francisco only underlined what I'm missing.

[tich]

http://www.stuff.co.nz/the-press/news/7 ... nly-be-dry

Interesting article on El Nino and what we could be in for this summer.

[Richard]

I would term "good" or "bad" weather as something thats presents a change from a extreme long running weather pattern, and that can often mean different things depending on where you are in NZ, like.. winter time where i am means an anticyclone can bring "bad" frosts, but in Northland may well be as considered as "good' weather.

[Bradley]

Scientists are suggesting that this years El Niño May last for longer then first thought:

http://m.smh.com.au/environment/weather ... kp821.html

[NZ Thunderstorm Soc]

Scientists are suggesting that this years El Niño May last for longer then first thought:

http://m.smh.com.au/environment/weather ... kp821.html

That's good, because I was getting bored by the persistent La Niña's of last few years.

[Richard]

Can the area of below average sea temperatures that now surrounds NZ which has broadened over the last two weeks be attributed to the current El Niño?, certainly explains why its been so cold over the last few weeks

[TonyT]

Yes, both the 82 and 97 strong El Nino events had a similar pattern of colder than normal water around NZ, but interestingly they also had colder than normal water right across the Tasman Sea, and didn't show the warmer patch you can see off the Australian east coast. While the colder than normal waters certainly have an effect (and will continue to do so through the summer). there has also been a substantial southwest airflow anomaly (which I expect to revert to more westerly through the summer), and that has been having at least as much an affect I believe.

[Richard]

Would be good if a moderator could add 2016 to the subject line.

Looking at SSTA for the 12th Jan what i find fascinating is the amount of cooler waters surrounding Antarctica, is this normal during a El Niño event?, also the cooler waters to the east of NZ have remained steady if not cooled slightly recently, but i would have expected this area to have promoted an increase of periods of high airpressure, which doesn't seem to have been the case.

The Tasman sea was starting to show pockets of cooling a week ago but these have disappeared.

[TonyT]

I'm not aware of a tendency for the Antarctic to show cooler then normal SSTs in an El Nino. Most indicators of Antarctic ice extent and air temperature suggest the Antarctic is around normal for the time of year, so its possible this is more of a data artefact in plotting the map, than a real trend.

I think there is a good chance we will start to see more blocking anticyclones east of NZ in the next few months.

[Richard]

I'm not aware of a tendency for the Antarctic to show cooler then normal SSTs in an El Nino. Most indicators of Antarctic ice extent and air temperature suggest the Antarctic is around normal for the time of year, so its possible this is more of a data artefact in plotting the map, than a real trend.

I think there is a good chance we will start to see more blocking anticyclones east of NZ in the next few months.

Yes, and maybe that blocking along with a slightly warmer Tasman (apart from northern areas) might promote slow moving areas of low pressure, like what the models are suggesting for Sun-Mon

[Richard]

Did anyone watch TV1 news last night where it was mentioned in one of there stories that because of the 'warmer the normal sea temperatures' that this will lead to a higher number of cyclones, am i current in saying this is not right as the warmer body of water is equatorial and to the north of the main breeding ground for cyclones, in fact temperatures in this area are below normal.

[Nev]

Did anyone watch TV1 news last night where it was mentioned in one of there stories that because of the 'warmer the normal sea temperatures' that this will lead to a higher number of cyclones, am i current in saying this is not right as the warmer body of water is equatorial and to the north of the main breeding ground for cyclones, in fact temperatures in this area are below normal.

SST's appear to be generally above normal across the tropical Sth Pacific atm, with the strongest anomaly being around the equator east of the dateline.

NOAA SST Anom. Pac - Jan 14.gif

However, actual temps are strongest (30C plus) in the west and central tropical Sth Pacific (particularly in the central-east where TC Victor formed).

NOAA SST Pac - Jan 14.gif

During El Nino, TC's are more likely to form further east than normal in the Sth Pacific. That's not to say more are likely to form overall. That really depends on the strength of the El Nino, which in this case is very strong, so probably more TC's overall.

[Richard]

Interesting learning how it all works, my understanding would be that thanks to the Coriolis effect, the early stages of pre TC Victor's storm clusters would have benefited from a northerly inflow from this eastern equatorial heat sink and that development happened near the boundary zone between this and the area of cooler than normal waters to the south, would this temperature gradient have helped in promoting increased instability leading to cyclone development?.

[NZ Thunderstorm Soc]

I'm just wondering if this El Niño is not really a El Niño but a stuffed up La Nina ?
Which should be a dry outlook, with El Nino over the summer months, we are, instead, getting more wet weather because of TC lows dropping down from the mid Pacific.
Where are the cold southerly changes with frontal thunderstorm activity in Canterbury as in past El Nino years?

[NZstorm]

would this temperature gradient have helped in promoting increased instability leading to cyclone development?.

TC are 100% tropical. So a temperature gradient does not favour TC formation it would hinder it.

[NZstorm]

I'm just wondering if this El Niño is not really a El Niño but a stuffed up La Nina ?
Which should be a dry outlook, with El Nino over the summer months, we are, instead, getting more wet weather because of TC lows dropping down from the mid Pacific.
Where are the cold southerly changes with frontal thunderstorm activity in Canterbury as in past El Nino years?

I reckon you may get a tstorm season in Canterbury March/April.

[03Stormchaser]

I reckon you may get a tstorm season in Canterbury March/April.

Thinking back over the last 12 years of chasing in Canterbury we have at times had very good late summer / autumn storms. Its just not what I expected this season.

[RWood]

I'm just wondering if this El Niño is not really a El Niño but a stuffed up La Nina ?
Which should be a dry outlook, with El Nino over the summer months, we are, instead, getting more wet weather because of TC lows dropping down from the mid Pacific.
Where are the cold southerly changes with frontal thunderstorm activity in Canterbury as in past El Nino years?

In the moderately strong El Nino of 1957-58 summer conditions were not dry in the Canterbury and Otago regions - eg for the Oct-March period Ashburton had 120% of its average rainfall. After cool, windy conditions over the country from October to January came this month:

February 1958: A wet month, with extensive flooding. It was also cloudy, warm and humid. Over the greater part of the country the rain was welcomed after dry weather in January, and stocks and crops benefited. In some inland districts of Canterbury and Otago conditions were considered too wet for sheep.

Rainfall: Rainfall was from two to four times the normal value in the Auckland province (except Gisborne) and also in most western and inland areas of the South Island south of Hokitika. From Kaitaia northward and in a small area around Hamilton totals exceed four times the average. In these areas it was by far the wettest February on record; and in Hamilton it was the wettest of any month in over 50 years of observation, Ruakura receiving 12.75”.

[Te Paki station,Te Hapua in the far north had 17.28”, almost 5 times the average.]

Heavy rain in the Auckland province on the 23rd and 24th caused unusually widespread flooding, affecting especially the King Country, the Kaitaia district, and the Waikato, Tongariro, Wanganui and Rangitikei rivers. The Auckland-Wellington railway line and main roads were closed for many days. Among the heaviest falls over the two days were 12” at Rangipo and 9.7” at Glenbrook, Otorohanga.

In the south, Milford Sound received a total of 69”, its highest monthly rainfall and not far short of the New Zealand record for a month of 73” at Homer Tunnel in February 1940 [since surpassed by a large margin]. The fall of 20.5” on the 12th at Milford was also one of the highest ever recorded in the country. The heavy rain extended to the Lakes district, and the Clutha River was in flood from about the 13th of the month.

Temperatures: Temperatures had been cooler than normal for the previous 4 months, but February was warmer than normal throughout the country. Departures were mainly 3F-5F, but were somewhat lower in eastern districts of the South Island.

Sunshine: Sunshine was more than an hour per day below normal, except in eastern districts of the North Island and on the Southland Plain. Over a considerable part of the South Island, from Central Otago northward, it was the cloudiest February on record, and in some places such as Nelson also by far the cloudiest summer month.

March 1958 was warm but dry in the east of the NI; April was cool, dry and sunny; May featured a lot of strong windflow from W & NW.

It was a particularly wet period in Fiordland throughout - Milford matched its annula average in the 6 months Oct 1957 - March 1958, and had 10015mm of rain for June 1957 - May 1958.

[NZ Thunderstorm Soc]

Where the hell do you get all your information from, there Rupert?
I was sorted gobsmacked reading your response to my claims that this is a more La Nina-ish form of weather pattern that the usual El Niño.
I'm starting to think, that the El Nino/La Nina weather systems, patterns are not a very good tool for forecasting weather into the future?

[NZstorm]

Recently I came across an article published in 1997 by a Canterbury weather expert saying that El Nino is not an indicator of drought for Canterbury. I think it was by a scientist at Lincoln.

[TonyT]

Where the hell do you get all your information from, there Rupert?
I was sorted gobsmacked reading your response to my claims that this is a more La Nina-ish form of weather pattern that the usual El Niño.
I'm starting to think, that the El Nino/La Nina weather systems, patterns are not a very good tool for forecasting weather into the future?

El Nino/La Nina is not an on/off switch for certain weather patterns. Its a lot more complicated than that.
1) start looking at the trends, not the absolute values
2) movements in the SOI have a significant effect on NZ weather patterns, if I get some time in the next few days I will try to illustrate that for you
3) MJO fluctuations can easily "override" what you might expect from SOI variations
4) ocean temperature anomalies can have an impact (read back some of the posts further up this thread)
5) there is a large random element in day to day atmospheric patterns: does your rubber duck always end up on the left side of the bath or does it move around a bit?

[RWood]

Where the hell do you get all your information from, there Rupert?
I was sorted gobsmacked reading your response to my claims that this is a more La Nina-ish form of weather pattern that the usual El Niño.
I'm starting to think, that the El Nino/La Nina weather systems, patterns are not a very good tool for forecasting weather into the future?

El Nino/La Nina is not an on/off switch for certain weather patterns. Its a lot more complicated than that.
1) start looking at the trends, not the absolute values
2) movements in the SOI have a significant effect on NZ weather patterns, if I get some time in the next few days I will try to illustrate that for you
3) MJO fluctuations can easily "override" what you might expect from SOI variations
4) ocean temperature anomalies can have an impact (read back some of the posts further up this thread)
5) there is a large random element in day to day atmospheric patterns: does your rubber duck always end up on the left side of the bath or does it move around a bit?

Makes sense. Personally when noting weather here in Nino seasons and looking back at old reports, no two have ever looked alike to me when examined in reasonable detail.

[RWood]

Where the hell do you get all your information from, there Rupert?
I was sorted gobsmacked reading your response to my claims that this is a more La Nina-ish form of weather pattern that the usual El Niño.
I'm starting to think, that the El Nino/La Nina weather systems, patterns are not a very good tool for forecasting weather into the future?

I already commented that El Nino events of the past - overall - have not been a good predictor of dryness in Canterbury. Much more so for the north and east of the NI, but there are still a lot of caveats.

The partial report above is copied from the old monthly summaries (supplement to the NZ Gazette over a very long period). I have all the copies of it and its successor publications from 1955 onwards. Libraries provided me with the opportunity to read all of the older versions going back to the 1850s. Then there were the annual summaries periodicals, etc.