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#1436617 - 11/10/2017 01:22 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: BIG T]
Rsav Offline
Weather Freak

Registered: 07/12/2016
Posts: 56
Originally Posted By: BIG T
where i grew up ( southern edge of Alstonville plateau ) we didnt have to go chase , the storms came right over us that often. Most narly one we experienced was in 1985 , amazing supercell that we thought we had missed until it turned due north and almost missed us to the west. Dropped a tornado across our farm for no more than a minute , but that was enough to wreck 2 fences & tip two old concrete lined tin watertanks over ( both had 1ft of water in them! ). funny thing i showed my old man the footage of the dunoon tornado a few yrs back and he joked , " oh bloody hell , the thing is still going" as it was so similar. I doubt we wouldve gone thru summer for two weeks without a storm right through the late 70s , into the 80s. Apologies if i have mentioned that storm before , think i have, but was just so awesome to see as a young fella.

I grew up in Ballina around the same time and remember the storm that hit Lismore (and then us) on the night of the last day of school in 1979, causing a fair amount of damage at Goonellabah.

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#1436618 - 11/10/2017 05:54 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
Squeako_88 Offline
Weather Freak

Registered: 23/09/2005
Posts: 390
Loc: Elimbah 4516
Looks like that wet signal for next week is becoming a very likely reality now. Very moist onshore flow feeding into a large upper trough right up and down the east coast of QLD with prospect of falls of 100+ right along the coast decreasing the further you go inland.
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#1436619 - 11/10/2017 06:49 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
Mad Elf #1.5 Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 2859
Loc: Mt Hallen QLD
The 8 day WATL is just simply amazing!
Gumboots weather if it goes off, bring it on!

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#1436621 - 11/10/2017 07:41 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 6551
Loc: Maryborough, Wide Bay, QLD
This setup has La-Nina written all over it...

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#1436626 - 11/10/2017 08:13 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Mega]
Bello Weather Offline
Weather Freak

Registered: 10/07/2012
Posts: 358
Loc: Bellingen NSW 2454
Originally Posted By: Mega
This setup has La-Nina written all over it...

Yep, been thinking the same for a few days - everything about the current weather says La Nina. We have talked before about the weather leading the event, reckon we are seeing it again this year.
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#1436630 - 11/10/2017 08:34 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
Blowin' Offline
Weather Freak

Registered: 23/08/2014
Posts: 847
Loc: Diamond Valley, Sunshine Coast
Agreed

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#1436631 - 11/10/2017 08:54 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: CirrusFibratus]
Ken Kato Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 4596
Originally Posted By: CirrusFibratus
Thanks for those anomaly charts Ken.

I've always been fascinated by how models can predict weather on a city-scale; with so many variables going on in the atmosphere all the time, and with everything having a knock-on effect on everything else, brilliant stuff.

The way I understand things is that it all starts at a synoptic scale, then from that level of detail you extrapolate more local, meso-scale weather effects, and then more detailed again for storm-scale systems. Is that a fair summation of things?


Basically, models are giant simulations of the atmosphere and oceans and all the known processes that go on inside them. Inside a model's atmosphere, clouds form, precipitation falls, wets the ground which then feeds back into the model's atmosphere, TC's form and move which sometimes cools the sea surface temps underneath, outflow boundaries from thunderstorms form, moist air is forced to rise over mountains causing clouds and rain, etc etc.

Contrary to popular belief, they don't explicitly factor in individual things like La Nina/El Nino, etc in a "if La Nina, then increase rain by 100mm here" or "if CAPE is 1000j/kg and seabreeze reaches Laidley, then form storms" in a formula kind of way - this is a myth.

Some of the newer convection-allowing models such as the HRRR used in the US can explicitly simulate individual showers, thunderstorms and other convective features forming in its atmosphere surprisingly well.

Speaking of the upcoming rainfall potential, here's the latest percentages of the 62 scenarios from three of the ensembles that are dropping a more than 25mm of rain during the next 8 days - it'll be highly dependent on whether the surface features including convergence zones and the upper troughs/lows behave as currently advertised:



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#1436633 - 11/10/2017 09:03 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
NotsohopefulPete Offline
Weatherzone Addict

Registered: 24/12/2008
Posts: 1085
Loc: Toowoomba
I missed the weather segment on the local ABC this morning so I have no idea what the bureau forecaster said but that chart looks great for Brisbane and the coast but for the rain-starved areas of the Downs it looks pretty grim.

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#1436634 - 11/10/2017 09:05 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Ken Kato]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 2711
Loc: Buderim
Originally Posted By: Ken Kato
"if CAPE is 1000j/kg and seabreeze reaches Laidley, then form storms" in a formula kind of way - this is a myth.


So how are storms forecast then? If its only the newer cutting edge models that can simulate individual showers or storms, and no such capability existed say 5 years ago?

I've always understood that some level of paramaterisation is written into the model which would model amount of convection at a point as a some formula based on parameters such as cape, upward atmospheric motion etc. Perhaps significantly more sophisticated than cape>1000 and seabreeze reaches Laidely, but ultimately a similar process.

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#1436637 - 11/10/2017 09:14 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Mega]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 2711
Loc: Buderim
Originally Posted By: Mega
This setup has La-Nina written all over it...


A lot of la nina characteristics in the atmosphere. One issue of interest to me is the high pressure ridging into the coral sea. This has been noticeable for a long time, and I don't think it is typical La Nina pattern. It may have significant implications for us if it continues with weak coral sea cyclone season, but interesting possibilities of tropical moisture surging down the east coast instead of heading out into the ocean as I think happened to some extend in NH summer just gone.

However the possible significant pattern shift I alluded to in the ENSO thread may have ended that.

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#1436639 - 11/10/2017 09:19 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
Ken Kato Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 4596
Yep Mike, unless it's a dedicated convection-allowing model like the HRRR, convection can only be parameterised through various techniques like the ones you mentioned. Other than these convection-allowing models, the other models don't directly forecast thunderstorms so there's no concrete way of telling whether these models are forecasting thunderstorms or just showers and rain areas unless it's clear-cut (deep enough convection to promote lightning, sufficiently vigorous updrafts, cloud microphysics, etc)... or algorithms that identify these characteristics.

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#1436643 - 11/10/2017 09:28 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Mega]
paulcirrus Offline
Weatherzone Addict

Registered: 08/08/2011
Posts: 1445
Loc: Brisbane - Windsor
Originally Posted By: Mega
This setup has La-Nina written all over it...

I was thinking the same thing. As when i saw the charts for the next week ( I know, only short term ) and Brisbane now getting overcast days whenever a southeaster arrives and the SOI levels, reads La Nina type setups. The question is, will it continue as a pattern into summer.
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#1436647 - 11/10/2017 09:39 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
paulcirrus Offline
Weatherzone Addict

Registered: 08/08/2011
Posts: 1445
Loc: Brisbane - Windsor
And I think the Highs are currently sitting in their normal place for this time of year without any irregular northern protrusions. I may make a call also on this years cyclone season. I agree with BOM with the 4 but their is a good possibility this season of more than that. I also think there will be more than one crossing, more like 3. Reasoning is that i don't think we will see the SE slide away from the coast this season as in the last few. Cyclones have been captured and flung to the south-east last few seasons. So It will be interesting if the nina gets going in November ( Rare for this to happen, but looks to be happening this year ) So I'm pretty happy about the overall setup for this year, which hasn't been the case when i looked at everything at this time of year for the last few years.
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#1436648 - 11/10/2017 09:46 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
LDRcycles Offline
Cloud Gazer

Registered: 14/03/2017
Posts: 16
Loc: Kin Kin, Qld
Fingers firmly crossed, we got 3 inches in the last lot of rain (which was the first of any significance since TC Debbie) which has greened things up but the soil profile is still very poor and all the creeks are dry. The drought is a long way from broken here, although the newspapers would have you believe otherwise of course.

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#1436650 - 11/10/2017 10:37 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: NotsohopefulPete]
Snapper22lb Offline
Weather Freak

Registered: 17/02/2015
Posts: 172
Loc: Golden Beach
Duty forecaster on ABC Sunshine Coast at 6:15 am did not discount 2-300mm over the next 8 days as suggested by WATL when quizzed by Rob Blackmore(Host). This is in no way indicative of the 7 day forecast for Maroochydore though. Next forecast will be much anticipated.

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#1436663 - 11/10/2017 13:32 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
NotsohopefulPete Offline
Weatherzone Addict

Registered: 24/12/2008
Posts: 1085
Loc: Toowoomba
Thanks Snapper 22lb

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#1436670 - 11/10/2017 14:40 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Seabreeze]
Mad Elf #1.5 Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 2859
Loc: Mt Hallen QLD
Stapy looking healthy west of Toowoomba.
Maybe lucky today!

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#1436694 - 11/10/2017 18:29 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Ken Kato]
CirrusFibratus Offline
Weather Freak

Registered: 17/09/2015
Posts: 284
Loc: Strathpine, QLD
Originally Posted By: Ken Kato

Inside a model's atmosphere, clouds form, precipitation falls, wets the ground which then feeds back into the model's atmosphere, TC's form and move which sometimes cools the sea surface temps underneath, outflow boundaries from thunderstorms form, moist air is forced to rise over mountains causing clouds and rain, etc etc.

Awesome, I didn't know models factored in things like that, thought it was strictly atmosphere-based. Thanks for sharing Ken.
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#1436695 - 11/10/2017 18:41 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: CirrusFibratus]
Ken Kato Offline
Weatherzone Addict

Registered: 05/03/2012
Posts: 4596
Originally Posted By: CirrusFibratus
Originally Posted By: Ken Kato

Inside a model's atmosphere, clouds form, precipitation falls, wets the ground which then feeds back into the model's atmosphere, TC's form and move which sometimes cools the sea surface temps underneath, outflow boundaries from thunderstorms form, moist air is forced to rise over mountains causing clouds and rain, etc etc.

Awesome, I didn't know models factored in things like that, thought it was strictly atmosphere-based. Thanks for sharing Ken.


The short & medium range models are mainly atmospheric based with sea surface temps forcing.

But many of the longer range ones such as monthly and seasonal forecast ones use fully coupled ocean-atmosphere systems which also include subsurface ocean modelling through various depths of the oceans.

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#1436710 - 11/10/2017 23:16 Re: SEQLD / NENSW Day to Day Weather - 2017 [Re: Ken Kato]
Rsav Offline
Weather Freak

Registered: 07/12/2016
Posts: 56
Originally Posted By: Ken Kato
Yep Mike, unless it's a dedicated convection-allowing model like the HRRR, convection can only be parameterised through various techniques like the ones you mentioned. Other than these convection-allowing models, the other models don't directly forecast thunderstorms so there's no concrete way of telling whether these models are forecasting thunderstorms or just showers and rain areas unless it's clear-cut (deep enough convection to promote lightning, sufficiently vigorous updrafts, cloud microphysics, etc)... or algorithms that identify these characteristics.

Are any of these newer models in use in Australia atm? If not, will they be in future?

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