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#1477333 - 27/11/2018 21:04 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Eigerwand]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
Originally Posted By: Eigerwand
Hmmmm, well the way I look at, the ocean or atmosphere, any system that is fundamentally driven by the distribution of energy, will restore to equilibrium in time. Whether this could be imagined to happen more ‘locally’ on either side of the Pacific by way of how I mentioned before or across the Pacific as a whole, I’d have to think about more. Balance is eventually restored, then it’s disrupted, and then It evens itself out again.


A Hmmm post should quote the source that prompted the reflections?

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#1477337 - 27/11/2018 21:12 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 19046
Loc: The Beach.
The hot air being driven through NE Qld is due to a Low situated over Central Eastern Australia that is very un-ElNino like. In fact it is forecast to deliver significant rainfall to NSW which is certainly not ElNino like.

That satellite water vapour image shows where the dry air originates.
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#1477346 - 27/11/2018 21:59 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
We are pretty much at the time of year where el nino influence on rainfall is negligible for everywhere except far north Qld.


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#1477348 - 27/11/2018 22:01 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Petros]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Originally Posted By: Petros
Whatever the ENSO state is, or is trending, look at the WV entering Aus via Pt Headland to Cairns atm!:



Keep in mind WV satellite shows water vapour in the upper atmosphere only. Substantially more water vapour is transported in lower level flows which do not show up on such satellites.

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#1477351 - 27/11/2018 22:06 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Originally Posted By: Mike Hauber
We are pretty much at the time of year where el nino influence on rainfall is negligible for everywhere except far north Qld.



Except that map gives an average for Nov - Jan, we’re only 25 days in Nov and we’re not in al El Niño. Plenty can & will happen over then.

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#1477381 - 27/11/2018 22:53 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 19046
Loc: The Beach.
Originally Posted By: Kino


Except that map gives an average for Nov - Jan, we’re only 25 days in Nov and we’re not in al El Niño. Plenty can & will happen over then.


Yes, we are only in November and as you state, not in ElNino.

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#1477386 - 27/11/2018 23:14 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 275
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtml
The depth animation sub surface warming looks to have intensified in last days?

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/olra_c.gif
Signature of -ve olr adjacent to area of westerly anoms(not quite wind bursts)

No sign of a stalling(strong) easterly forecast this time....

Forecast, forecast, forecast.... very tempting to suppose that the xmas goose is cooked.


Edited by snowbooby (27/11/2018 23:15)

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#1477396 - 27/11/2018 23:37 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Sillybanter Offline
Weather Freak

Registered: 17/03/2017
Posts: 58
Loc: Toowoomba
I don't want to be inflammatory but El Nino doesn't really control the day to day weather in a sense does it. The lows over central Australia could happen in or out of an el Nino. SAM would have more of an impact on the current events I would have imagined.

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#1477417 - 28/11/2018 06:24 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Originally Posted By: Kino


Except that map gives an average for Nov - Jan, we’re only 25 days in Nov and we’re not in al El Niño. Plenty can & will happen over then.


The map shows that in an El Nino for most of Australia there is no influence on rain between Nov and Jan. And we are now 28 days into that period (or 27 when I posted it).

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#1477448 - 28/11/2018 08:19 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
The last big Kelvin wave is now on its way out. The next one wont' be as strong, and with heat content back to average in the west I'd say that will continue to be the case and we're likely past peak heat content. Its also noticeable that the 20C depth is normalizing more than the overal heat content. The heat is still there, but its becoming shallower.



Have a look at the growth of the western subsurface cold pool in 97/98. For other el nino years the size of the subsurface cool pool doesn't seem to have a strong impact on next year's La Nina prospects, but I think in 97/98 the extreme size of the cold pool pretty much demanded that the next year would be strong La Nina. For other years I think it depends more on whether trades in Autumn tend to be more westerly or easterly.


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#1477471 - 28/11/2018 09:25 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Sillybanter]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 19046
Loc: The Beach.
Originally Posted By: Sillybanter
I don't want to be inflammatory but El Nino doesn't really control the day to day weather in a sense does it. The lows over central Australia could happen in or out of an el Nino. SAM would have more of an impact on the current events I would have imagined.


Maybe and I don't see your post as inflammatory. However Livio Regano said he has not seen Lows that originated in the south of the country in November move so far north in his entire time at BoM and Retired Weather Man said he saw it last sometime back in the 50's so it's a fairly exceptional event.

Heatwaves and westerlies are certainly not unusual in any ElNino event but the placement of the Low would be very much so. Of coure we have not had an ElNino declared and as I have stated previously, the problem lies in the Indian Ocean. The crazy twist in the tail is that the same Low that dragged record heat over north eastern Australia just a couple of days back is drowning parts of NSW on its southern influence and its northern influence is fanning one of the worst fires seen in Qld.

The type of rain being witnessed in NSW is more typical of when ElNino typically decays.
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#1477473 - 28/11/2018 09:28 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Certainly throws this map right out the window...


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#1477475 - 28/11/2018 09:31 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 19046
Loc: The Beach.
Yeah that's why I put it up. It tells a little more truth than the other one posted as it centres current time frames.

I heard the news suggesting this is the worst November storm in Sydney for 44 years.
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#1477480 - 28/11/2018 09:36 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
The role of East Coast lows on rainfall patterns

Quote:
ECLs are identified as a significant factor in the weakened relationship between ENSO and rainfall in the ESB,
articularly in southern parts; however, these are not the only factor, with local topographic effects also likely to play a role.


Quote:
Existing studies have found little to no relationship between ENSO and either ECL frequency or intensity. Hopkins and Holland (1997) identified a small tendency for ECLs to occur during periods of rapid, negative to positive, changes in the Southern Oscillation Index, but no similar results were observed using a comprehensive ECL database in Wiles et al. (2009).


The current rainfall from an east coast low has nothing to do with ENSO.

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#1477482 - 28/11/2018 09:40 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
If you consider the oct - Dec and Nov-Jan maps together, the obvious conclusion is that for many areas of Australia there is a signficant drying influence for SE Australia in October but not November.

Eg:

Oct -40mm
Nov 0mm
Dec 0mm
Jan 0mm

Average October to December and you get dryer than normal conditions. Average November to January and you get normal conditions.

And the current heavy rain is in coastal NSW, which even on Oct-Dec shows normal conditions.

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#1477485 - 28/11/2018 09:46 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 19046
Loc: The Beach.


East Coast Lows generally have much shorter lifetimes than tropical cyclones and last only a few days. They develop over the Tasman Sea close to the east coast and can intensify rapidly in the overnight period. Unlike tropical cyclones, where the warm seas provide the energy source, East Coast Lows are driven by a dynamic interaction between cold air in the high levels of the atmosphere over the continent, and the surface temperature gradient between the land and the relatively warm Tasman Sea air. They can produce gale to storm-force winds, very heavy rainfall and in some cases coastal inundation."


This Low originated in the Bight. It is not an ECL.
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#1477486 - 28/11/2018 09:48 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Originally Posted By: Mike Hauber
The role of East Coast lows on rainfall patterns

Quote:
ECLs are identified as a significant factor in the weakened relationship between ENSO and rainfall in the ESB,
articularly in southern parts; however, these are not the only factor, with local topographic effects also likely to play a role.


Quote:
Existing studies have found little to no relationship between ENSO and either ECL frequency or intensity. Hopkins and Holland (1997) identified a small tendency for ECLs to occur during periods of rapid, negative to positive, changes in the Southern Oscillation Index, but no similar results were observed using a comprehensive ECL database in Wiles et al. (2009).


The current rainfall from an east coast low has nothing to do with ENSO.


Problem is, this isn't an ECL. It's a cut-off low with rapid cyclogenesis as it hits the warmer Tasman Sea due to the thermal gradient.

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#1477490 - 28/11/2018 09:58 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Sillybanter Offline
Weather Freak

Registered: 17/03/2017
Posts: 58
Loc: Toowoomba
So we could say its elino like conditions on the north side of the low and la Nina like conditions on the Southside. I don't see the need to reference ENSO every time a weather event occurs it the kinda sensationalism that drives the media these days. Its wet on the southern side and dry on northern side of a low and that is not new.The lows position is slightly odd for this time of the year but whats more unusual is that we have had several similar systems in a row dragging the dry air a little further east every time.

Originally Posted By: ColdFront
Originally Posted By: Sillybanter
I don't want to be inflammatory but El Nino doesn't really control the day to day weather in a sense does it. The lows over central Australia could happen in or out of an el Nino. SAM would have more of an impact on the current events I would have imagined.


Maybe and I don't see your post as inflammatory. However Livio Regano said he has not seen Lows that originated in the south of the country in November move so far north in his entire time at BoM and Retired Weather Man said he saw it last sometime back in the 50's so it's a fairly exceptional event.

Heatwaves and westerlies are certainly not unusual in any ElNino event but the placement of the Low would be very much so. Of coure we have not had an ElNino declared and as I have stated previously, the problem lies in the Indian Ocean. The crazy twist in the tail is that the same Low that dragged record heat over north eastern Australia just a couple of days back is drowning parts of NSW on its southern influence and its northern influence is fanning one of the worst fires seen in Qld.

The type of rain being witnessed in NSW is more typical of when ElNino typically decays.

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#1477493 - 28/11/2018 10:15 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ashestoashes Offline
Weather Freak

Registered: 22/10/2017
Posts: 739
Loc: Voyager Point (South West Sydn...
I wonder what influence this Ningaloo Nina has been exerting on our weather I feel like it's often under-appreciated. Since these conditions have been going on for a reasonable period of time.

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#1477500 - 28/11/2018 10:34 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Description of the East Coast Low database As used by the BOM and studies finding no relationship between ENSO and ECL activity.

Quote:
The six types are:... ex-tropical cyclones (4 per cent), ....and lows in the westerlies (3 per cent),the latter two of which originate from mid-latitude low pressure systems or fronts in the westerlies.


East Coast lows specifically includes both lows that form in the Tasman Sea, and low pressure systems that move into the Tasman Sea, whether they were originally cyclones, or mid-lattitude low pressure systems.


Edited by Mike Hauber (28/11/2018 10:35)

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