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#1425097 - 04/06/2017 11:30 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
Eevo Offline
Weatherzone Addict

Registered: 02/11/2013
Posts: 1610
Loc: Bridgewater
overnight -0.1 here

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#1425130 - 04/06/2017 23:23 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7166
Loc: Adelaide Hills.
Originally Posted By: ThD Ht
thanks for your reply Seira,
those equations the models use include some of the effects and
principles you mention but they also certainly do not include
others you mention.
thus when analysing models its important to take these local
anomolies into consideration and forms part of the art of reading
models for local area forecasts.

you said..........
"It is more important to me to understand processes at work,
than to say lets following/trust in a models output
data/graphs, be it one model or several."

i think any meteorologist worth their salt will agree and
abide by that statement, i was going to say we all know how
notoriously unreliable models are but i think a more accurate
observation would be how notoriously unpredictable models can
be, i.e.- one minute they can be surprisingly accurate and
the next they can be obnoxiously inaccurate.
i see what your on about now, not so mysterious and arty
farty after all, just the way you write makes it sound that
way. smile
i appreciate your clarification and discussion.

so having got that out the way i emailed a friend that i'm
a tad concerned about the end of this cropping season in as
such in light of the seasonal offset i talked about previously
i think s.a. farmers may be in for a bit of a hard time
weatherwise around the end of this season.
any thoughts on this Seira or is it too far out to talk about?

TH

Clarification and discussion acknowledged smile .

East Coast specifically Wollongong/Sydney area looking at probable winter storm conditionsbut for us:

Written 29th-30th of May [today in this bracket]:

The next few short-wave upper troughs will likely peak with an axis in the Southern Indian Ocean, due to the higher-pressure system being blocked in the east (near Bass Strait) a more robust upper low there has strong southern/polar maritime winds on the western flank. For there to be an upper-trough axis peaking in the Indian Ocean, there needs to be a ridge-gap, with some remnants of middle or upper level moisture hitting a temperature gradient (with reduced isoheight thickness). The 540- and 532- thickness contours would be along the upper trough north-south axis peak, just further south.

A few ridge-gaps later (as the main longer-wave trough moves east towards Perths longitude), the sub-tropical ridge is given the opportunity to move further south and east (forming a < shape, longitudinally), the corresponding upper low near Bass Strait having moved east as well.

The next ridge-gap would thus form in the Bight, disrupting the longer-wave trough system to the Southwest, with the strengthening high (in the Bight) being wedged between the 576- and 540-thickness contours (thus becoming a V shape). This enables the longer-wave trough (southwest) to rear up and form cut-off/s or fronts (plural), separated by the sub-tropical ridge. It is then a matter of where the main colder-air masses are in polar regions as to whether the LWT will rear up scouring the Bight, or slightly more east (Adelaide). If polar maritime air pushes another plume of cold upper air up into the SE Bight, Adelaide will receive the system, whether it is cut-off or strong front. There is not enough ridge blocking to stop this.

It looks to hinge on the polar maritime upper plumes [East Coast is far more certain till now.
Vertical thickness of troposphere (due to colder air) will affect ability of moisture to rainout without temperature differences colder, drier air over SA due to SE-ESE wind drift from strong high.

My bit worth smile .

Eevo has it with negative overnight lows!]


Edited by Seira (04/06/2017 23:25)

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#1425131 - 05/06/2017 00:04 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
betsuin Offline
Weather Freak

Registered: 07/04/2010
Posts: 582
Loc: Magill, Adelaide
Nice moon Ring - hard to get it all in - I need a wider lens!



PS: That's Jupiter lower left of the Moon.


Edited by betsuin (05/06/2017 00:05)

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#1425132 - 05/06/2017 05:15 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
godzilla highs look to be here for another week or so yet.
any significant polar pulse and associated rain is pie in
the sky as is anything capable of delivering a good soaking
atm. i don't think it'll crack until after the solstice. when
it does i think then we can all put our collective heads between
out collective knees and kiss our collective butts goodbye.
it had better be like that or this season gunna end up a disaster.

overnight mins. here remaining in the mid to high singles
although reynella high oval was frosted to the max yesterday
morning.

TH
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#1425164 - 05/06/2017 11:46 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
rstewart84 Offline
Weatherzone Addict

Registered: 17/01/2007
Posts: 2077
Loc: Kalangadoo,South Australia
I think you maybe right about the season possibly ending up a disaster Thunda as it seems the tide has turned on SA with godzilla highs ridging in the bight killing off any hopes of winter storms or strong fronts/cut off lows as that diminished last week with the supposed winter storm we were meant to get dying in the butt as it entered the bight

Have yet to download recent data from the weather station onto my laptop but i am pretty sure Saturday and Sunday morning last weekend were bone chillers as well with temps getting into the 0-negative ranges down this way

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#1425201 - 05/06/2017 17:31 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
i'm not predicting a disaster RS, more a late season onslaught
of vile winter weather with wind, rain and cold, which if the
rain doesn't happen will be somewhat of a disaster for croppers.
refer back to previous post for further elaboration.

TH
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#1425205 - 05/06/2017 17:36 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
Eevo Offline
Weatherzone Addict

Registered: 02/11/2013
Posts: 1610
Loc: Bridgewater
like last year?
from memory, most of the rain and wind happened in the second half of winter and in spring.

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#1425216 - 05/06/2017 18:46 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
teckert Offline
Weatherzone Moderator

Registered: 27/05/2001
Posts: 17524
Loc: NE suburbs, Adelaide, South Au...
Eevo, last year the rains started in May and just kept to going to January....

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#1425232 - 06/06/2017 00:17 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
yer memory can be a fickle, elusive and very a selective thing
sometimes which is why police have so much trouble getting an
accurate account of events even after something has just happened.

yer the rains went through to the end of january but as far as
seasons setup goes we had a couple of false starts to 'summer'
in sept. and nov. but it basically remained 'winter' until
christmas when the summer kicked in with a vengeance with the
first big tropofest.
and without getting carried away with research that's from
what i remember, feel free to correct me if i'm wrong Teck.

all models have relatively fine weather with no significant
frontal activity for the forecast period but interesting to note
current extended gfs has a longwave trough and huge polar pulse
approaching against a weakening tasman high around the 21st.
the 21st?!......now that date rings a bell.......
the chances of this finalising itself in it's current draft is
0-5% but imo things are going to crack with something similar to
that eventually.

had just enough light drizzle to wet the concrete a little
around 6pmish last night, associated remnant dregs of that
passing cold front, at least with the associated remnant
cloud cover it's nice and warm tonight, a balmy 12 here.

TH
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#1425438 - 07/06/2017 13:58 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
Markus Offline
Weatherzone Moderator

Registered: 02/12/2010
Posts: 2126
Loc: Clare, SA
Baha, models keep getting worse by the day. Even 16 day GFS which nearly always has something has drizzle at best LOL. These highs are linking up in a way quite reminiscent to me of the year 2006 I think it was, I think I remember some 1040 + highs that year. Really pushing the memory bank on that one though.

Might end up with some very impressive nighttime temperature anomalies for June if this keeps up!
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http://markdawsonphoto.wordpress.com/

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#1425600 - 09/06/2017 01:24 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
got a coupla mil from some half decent extended precipitation
ranging from light shower to heavy drizzle yesterday afternoon.
quite a surprise since i had already relegated the day into a
long since overflowing zilch bin.
hark, is that a bit of a 'mini',(sorry TS), coldpool i see
approaching around the 16th.
i await with trepid anticipation the approach of another half
hearted clapped out mistimed poor excuse for a weather event
and continue to freeze my nuts off in the process.
that is of course if it ever manages to come to fruition at all.


TH
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#1425645 - 09/06/2017 13:33 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
puddles Offline
Weather Freak

Registered: 19/01/2007
Posts: 180
Loc: Reynella, SA
Good to see the Buckland Park radar is up and running again. smile

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#1425675 - 10/06/2017 08:08 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
yer, pity there's nothing of any consequence to test it on.
the subtropical ridge is really doing a number on us that's
for sure.
been in bed the last 14hrs with a mongrel cold, nothing a
hand full of pills and a grain of ricin won't fix.
gfs extended still got something happening around the 21st,
'bout the only straw we got to clutch onto at the moment.
actually quite warm,(and i use the term loosley),here last
night hovering just under 10 instead of the usual just over 5.

TH
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#1425729 - 11/06/2017 03:37 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
well bugger me, there's always something new to learn eh?
just looked at the weather news column on WZ.
SAM, good l SAM is responsible for this, the Southern
Annular Mode or could also be called the APO, Antarctic Polar
Oscillation. seems like it expands and contracts its bellows
like a breathing behemoth either expanding in a -ve phase
and smashing us with cold fronts or retracting into a +ve
phase leaving us with this....."beautiful fine weather" we
have now.

i seem to detect a slight anomaly in the report though.

quote from the report:-
----------
In the next two weeks SAM looks to become stronger negative,
which means that the high over southern Australia is not
going anywhere.
----------
if SAM becomes stronger negative(further/stronger expansion) it
means it should push harder north and tend to displace the high
which is at odds with the comment they are not going anywhere.
however if the report said 'stronger positive'(further/stronger
contraction) then it would make sense to say that the high is
not going anywhere.
does anyone agree with this or am i reading the report wrong?

one other thing that irks me is it seems for whatever reason
the +ve/-ve thing is arse-about-face, the natural way of
looking at it would be a contraction to be -ve and an expansion
to be +ve.

aside from that, for me this expansion/contraction thing makes
perfect sense and is just another factor in the growing heap
of climactic influences and planetary meteorhythms that affect
our weather here.

TH
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#1425800 - 12/06/2017 13:11 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7166
Loc: Adelaide Hills.
I agree (regarding the SAM), + would be expansion, and so on.

Unfortunately, the definition of the SAM includes the entire southern hemisphere between 40 and 65 degrees south*, so its not just about whats below/near Australia.

*Gong and Wang, Geophysical Research Letters, 1999.
Originally Posted By: ThD Ht
is just another factor in the growing heap
of climactic influences and planetary meteorhythms that affect
our weather here.

I like that laugh smile .

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#1425844 - 13/06/2017 01:06 Re: South Australian and Adelaide day to day forecasting [Re: Seira]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
Originally Posted By: Seira
Unfortunately, the definition of the SAM includes the entire southern hemisphere between 40 and 65 degrees south*, so its not just about whats below/near Australia.


yes you are right when you say it's all round and not just
australia and also includes of course NZ, tip of south
america and south africa.
i'm not sure why you say 'unfortunatley', its just the way
it is.
just looking at the acronym, the a for annular, it has a
possible double meaning, annular as in circular, i.e.-the
donut shaped belt you describe or annular as in yearly.
i have known since the early days the antartic polar influence
expands and contracts with the seasons but this being the
case simply puts it out of sync. and in a seasonal offset
and falls into what i'v been waffling on about for a while now.

however....having said that, after a little light reading on
the subject it is clear the annular is associated with
latitude and not yearly. in fact the Southern Annular Mode has
been named just that to get it away from any association
with the annual Antarctic Polar Oscillation as SAM is regarded
as in no way influenced by seasonal change any more than is
the IOD or the SOI and is about as fickle and predictable.
where as the IOD and SOI are oceanic/surface based phenomena
the SAM is more mid/upper atmosphere based.
the jury is still out on the whys but at least like the others
it's an observable and measurable phenomena.

BOM says SAM was a significant contributor to the big dry
between 1997 and 2010, thats a long time.
i can remember saying back around the mid'00s that things have
changed and that was the way things were going to be from now
on and to get used to it, then everything went back to 'normal'
the good news at the moment is my mate up at bute is not yet
worried because he has the good subsoil moisture from summer
that his crops are now tapping into. unfortunately that is not
the case for everyone, the bad news is this has the potential
to last for the whole season, that there is no light at the
end of the tunnel, that things are not going to crack
eventually. that sucks. like a lot of other people, i just
wish it would bugger off back to the -ve and give us a
break(pun intended).
and heaven forbid this is not the start of another long winded
drawn out multi-year trend.

TH
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#1425869 - 13/06/2017 10:48 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
berga1987 Offline
Weather Freak

Registered: 04/08/2010
Posts: 339
Loc: Malvern, Adelaide, Aus
The 1997 - 2010 dry period killed mosquito creek. frown


Edited by berga1987 (13/06/2017 10:48)
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I wish Mt Lofty was more lofty, another 2km or so would suffice.

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#1425906 - 13/06/2017 18:27 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
your not kidding, the bool, cocky and mullinger as well.

TH
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#1425909 - 13/06/2017 20:15 Re: South Australian and Adelaide day to day forecasting [Re: ThD Ht]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7166
Loc: Adelaide Hills.
Originally Posted By: ThD Ht
Originally Posted By: Seira
Unfortunately, the definition of the SAM includes the entire southern hemisphere between 40 and 65 degrees south*, so its not just about whats below/near Australia.

i'm not sure why you say 'unfortunatley', its just the way
it is.

Unfortunate because it is a global (southern hemisphere) climate phenomena, so for reasons of consistency (and probably fairness), it probably needs to thread of its own (or one that can be reinvigorated).

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#1425926 - 14/06/2017 01:49 Re: South Australian and Adelaide day to day forecasting [Re: Thunderstruck]
ThD Ht Offline
Weatherzone ratbag

Registered: 02/03/2002
Posts: 3917
Loc: Reynella, S.A.
yer i wasn't going to get too much more carried away here, just
as it was relevant to our current weather and to bring it to
others(who may be interested) attention, plenty of further
reading at your local library.
they were barking on the news that it's been the driest start
to winter in 60yrs,(1957).
be interesting to see what that particular stat shows when/if
things do finally crack.
gfs and access still both have a few crumbs of something around
the solstice and something of more significance around the 25th.
at 11 days out it's still well and truly in 'pie in the sky'
territory but at least there's something there to turn ones nose
up at.

TH
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