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#1501021 - 23/06/2019 00:14 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
amphetamarine Offline
Weather Freak

Registered: 18/03/2004
Posts: 363
Loc: Cairns
Hence why iam dubious on graphs

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#1501134 - 24/06/2019 16:56 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Thunderstruck Offline
Lightning man

Registered: 10/05/2001
Posts: 15024
Loc: Seaford Meadows, SA
Negative to neutral IOD doing it's best to setup atm, been some very large changes in the last few weeks over the western Indian, fair deal of cooling whilst some nice warming closer to home, eroding the Nasty Ningaloo Nina to pretty weak levels now. So for now we have a bit of a lull whilst WA gets all the chocolates and then it should come back again for the S/SE of the country, but overall after a bad first 4 months, things are looking much better this year than last.

TS cool

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#1501163 - 25/06/2019 10:19 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
Agree TS. At present:

* the only equatorial monsoonal cloud is over MJO zones 2 & 7 - yet MJO is null at zone 6 and expected to stay that way for a while
* Pacific trades are strong through Nino1.2 all the way into Nino.4
* Pacific SSL is flat through the Nino regions, but showing cold water under MJO zones 6/7 and over East at Nino1.2
* SST is only 24C at Nino1.2, trades are pushing this into Nino.3 which is no longer anomalously warm
* Sub SST temps have large cool areas under the Western and Eastern regions of EQ Pacific
* IOD seems to be heading towards negative going by the dramatic cooling off Africa past week, and either way, has warm water NW of Aust

This to me is a sign that the present neutral Nino conditions are tending towards a transition to La Nina.

BUT - there is a significant easing of the present strong Pacific trades predicted to commence in a couple of days. Wonder were this takes us, and how long it might persist?

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#1501169 - 25/06/2019 11:32 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
BoM update their ENSO outlook today so that will give us an idea where they think things are heading. Still think given the current conditions that they possibly may downgrade to inactive, though most likely will stay on the alert side of things.

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#1501179 - 25/06/2019 15:09 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Originally Posted By: BoM
The immediate likelihood of El Niño developing has passed, meaning the ENSO Outlook has been reset to INACTIVE. While the possibility of El Niño can't be completely ruled out for 2019, the tropical Pacific Ocean is more likely than not to remain in an ENSO-neutral phase over the coming months.

Model outlooks indicate a positive Indian Ocean Dipole is likely to drive Australia's weather for much of the rest of 2019, meaning the likelihood of a drier than average winter–spring remains.

Oceanic and atmospheric indicators are now largely at ENSO-neutral levels. Tropical Pacific sea surface temperatures have cooled over the past fortnight but remain slightly warmer than average. Cloudiness near the Date Line and trade winds have been close to neutral over recent weeks, while the Southern Oscillation Index (SOI) has hovered around El Niño threshold values over the past month. With little anomalous warmth in the ocean sub-surface, most climate models indicate the tropical Pacific will continue shifting further away from El Niño thresholds through the winter.

In the Indian Ocean, waters remain average to cooler than average in eastern parts, and warmer than average further west; a pattern typical of a positive Indian Ocean Dipole (IOD). While the IOD index fell below the positive IOD threshold this week, climate models indicate this is likely to be temporary, with positive IOD values forecast to persist through winter and into spring. Typically, a positive IOD brings below average winter-spring rainfall, above average temperatures, and an earlier start to the fire season for southern and central Australia.

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#1501193 - 25/06/2019 17:53 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
Thanks Kino.

Interested in BOM's +ve IOD outlook. I reckon they will be proven to be wrong, ......but that is only my humble less educated observation based on current Indian Ocean surface temperature measurements now, compared to how it has transitioned over the past month, coupled with what I feel is lesser north moving ocean currents off Perth over the same period.

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#1501217 - 26/06/2019 07:05 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Cooling in the east, but since the late summer/autumn break down period has ended the dateline warm pool has if anything strengthened. The warming with the May WWB was noticeably stronger than the cooling with enhanced trade winds during the Indian Ocean side of the MJO cycle.



Classic el nino modoki, and models forecast more of the same, with further cooling in nino 3, less cooling in 3.4, and no cooling in nino 4.

On IOD CFS is not having a bar of the forecast +ve IOD and forecast Indian Ocean SSTs looks dead neutral. BOM do not consider CFS, not sure if that is because it is no good at forecasting IOD, or perhaps because CFS does not issue a specific forecast for the IOD index (but presumably BOM could still calculate it for themselves from CFS grid data).

The trend towards +ve IOD has certainly eased as the westerly activity in Pacific has eased over the last few weeks. Forecast for the next two weeks is for the current WWB to develop further, and for easterly anomalies to develop in the east Indian Ocean at the same time, so presumably we will also see renewed cooling there in the next week or two. GFS seems to have much weaker easterlies forecast than EC, which seems to correspond to CFS not being interested in a +ve IOD.

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#1501218 - 26/06/2019 07:36 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 19046
Loc: The Beach.
The Indian still dictating our weather just as it has done the past couple of years now Kino.
_________________________


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#1501229 - 26/06/2019 10:14 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
Mike a warm pool at dateline to N.G. is to me, Nino neutral, esp. when temps in Nino3.4 are cooler.

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#1501234 - 26/06/2019 11:05 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Classic Modoki? One cannot be serious. Dead neutral, as I (and others) predicted. Nothing happening in the Pacific at all, all the action is Indian & Southern based at present. Hopefully that -AAO delivers.

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#1501235 - 26/06/2019 11:26 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: Petros]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Originally Posted By: Petros
Mike a warm pool at dateline to N.G. is to me, Nino neutral, esp. when temps in Nino3.4 are cooler.


From Ashok et al which defines Modoki:



Warmest temperatures in el nino modoki are right on the dateline.

Even in a weak non-modoki el nino such as 06/07 warm water on the dateline is prominent, with warm water to the east appearing later and joining the dateline warm water only near peak. Throughout the entire event westerly anomalies were on the western flank of the dateline warm pool.



Warm water on the dateline is the prime engine for driving an el nino.

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#1501236 - 26/06/2019 11:28 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
KevD Offline
Occasional Visitor

Registered: 23/09/2001
Posts: 5236
Loc: Bellingen NSW 2454
With you on that one Kino. Dead neutral right now and if you look at the patterns there is an increasing amount of cold water moving across under the Pacific. Looks like a definite neutral or Nina to me. The last WWB did very little and there is no immediate sign that I can see of another one any time soon. About time too. Had enough of this dry.

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#1501244 - 26/06/2019 15:08 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 275
I would have thought the current OLR supports warm modoki

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#1501271 - 27/06/2019 01:32 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Thunderstruck Offline
Lightning man

Registered: 10/05/2001
Posts: 15024
Loc: Seaford Meadows, SA
I'm a little miffed as to why the Bureau have mentioned Severe Tropical Cyclone Vayu as a possible cause of the colder water over the western Indian near the African coast...it was nowhere near there!

Quote: "The latest fall in the IOD values is simply due to average to cooler than average waters right on the African coastline, most likely generated in association with severe tropical cyclone Vayu."

That really has me beat, must be out by 2000km as it was right up the western Indian coast.

Things continue to show more of a dive to neutral and beyond, it will take a fair sudden reversal to get warm water in the western Indian now with sub-surface pretty damn nippy, and now the Central/west Indian is cooling fairly strongly also. Pretty interesting.

Meanwhile nino 3.4 is 0.01 and falling down Mariana's trench.



TS cool


Edited by Thunderstruck (27/06/2019 01:33)

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#1501276 - 27/06/2019 06:51 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
LonnyDave Offline
Cloud Gazer

Registered: 08/05/2018
Posts: 47
What are the climate drivers for the current heatwave in central Europe?

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#1501281 - 27/06/2019 09:57 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
SLP pattern last 30 days:



Tropical low pressure has moved away from Australia in both directions and is enhanced over west Indian Ocean, and near the dateline. In both cases this is following warmer tropical waters. However due to the differing nature of the Indian and Pacific oceans the enhanced convection in west Indian causes cloudy weather, and an increase in evaporation due to an increase of the normal westerly wind. So cooling. Changes to upwelling and E-W distribution of water have little impact as E-W and surface-depth temp gradients are weak.

In contrast convection in is causing a new westerly wind burst, which will reduce the typical easterly wind based evaporation, and reduce the transport of cooler water from below and from the east, and result in warming.

Pressures generally over Australia are significantly higher than normal. The 30 day SOI is over el nino threshold, and 90 day a bit below. Pressure near Tahita and through SE Pacific are generally high, with an enhanced high pressure reflecting a cool SPMM and acting to push cooling into the east Pacific. If it wasn't for the elevated pressure in these regions SOI would be a fair way above el nino threshold.

The North East Pacific shows low pressure anomalies, and reflects on going warm NPMM, which helps keep SSTs warm near the dateline.

Modoki pattern is reflected in that tropical convection is enhanced near dateline, but not further east, where it would be in an east based el nino. Main differences in resulting atmospherics are on the East side of the Pacific with the West side where we are acting pretty similar to an east based el nino.

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#1501285 - 27/06/2019 12:25 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Another massive volcanic eruption, this time at PNG:

Impressive image of the strong eruption that recorded today the volcano in Papua New Guinea, considered one of the most dangerous in the world.

It is estimated to reach a height of 19 kilometers, it was a subpliniana eruption (26/06/2019)

This will have an impact on ENSO zones - be interesting to see what.

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#1501290 - 27/06/2019 13:27 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ashestoashes Offline
Weather Freak

Registered: 22/10/2017
Posts: 739
Loc: Voyager Point (South West Sydn...
No wonder the BOM went on Inactive, look at the trend on Nino3.4.


Also looks like the Indian Ocean is taking a big dive as well hopefully continues we certainly need the break.

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#1501293 - 27/06/2019 14:51 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 275
..storm alvin(about 110w) is tagged at 14n
... probability of a cyclone forming @ 140e(about same latitude) is currently categorised as highly probable
https://www.ssd.noaa.gov/PS/TROP/

Both appear to be forecast on a somewhat s-e track

could either of these enhance any anomalously westerly influence?


Edited by snowbooby (27/06/2019 14:52)

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#1501295 - 27/06/2019 14:53 Re: Climate Driver Discussion 2019 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
They're all dropping rapidly...or in other words (warning may have a triggering effect) - COOLING smile



And Nino 4 totally destroys any Modoki talk given it is also cooling when it should be warming etc. Great call by the BoM re: ENSO.

Re: TS comments re: the cyclone and impacts on SST's - could it be that there is a significant fetch on the inflow? This could definitely cool SST's on the WestInd?


Edited by Kino (27/06/2019 14:54)

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