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#1501504 - 01/07/2019 20:17 Re: NSW Day to Day Weather - January to July 2019 [Re: Jac0b]
Eigerwand Offline
Weather Freak

Registered: 28/05/2012
Posts: 526
Originally Posted By: Jac0b
Definitely, the continental climates can deviate much more from their average due to having no ocean buffer. February 2019 had average monthly temperatures about 15°C below average in some towns across western Canada and northwestern USA. That would never occur here. Likewise, some months, e.g. May 1934 or March 2012 were over 10°C above average in parts of the Midwest USA.

In Australia a monthly mean that deviates even by 3°C is significant, whereas in the continental climates it's normal.


Indeed. I can imagine the variance in such data that would be observed in a small sample of months in such extreme climates would be problematic. But of course if there is some kind of background 'climate', get enough years together and like you mentioned, the variances should swing both ways thus giving some idea of what can be considered average and from there you can get some idea of what are typical and atypical months whilst taking into account that it takes a greater temperature deviation to correspond to a statistically significant anomaly.

In the case of Australia without the extremes of such continentality, off the top of my head as per the central limit theorem, I'd roughly estimate the level of significance for temperature anomalies around much of Australia to be something like:

+or- 1.2C = to 1standard deviation (sd) from the mean, (68% of months to fall within this range),

+or- 2.4C = to 2sd (95% of months to fall within this range) and,

+or- 3.6C = to 3sd's (99% of months to fall within this range).

From a statistical point of view, the trouble we seem to have in Australia when it comes to identifying the true mean, is that we appear to have a moving average. This is illustrated by the imbalance in frequency of months with anomalies of 3 to even 5C above average, yet very few months where the anomalies have gone the other way by a SIMILAR magnitude.

Very important that, the central limit theorem when discussing climate averages..

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#1501510 - 01/07/2019 21:28 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Blair Trewin Offline
Weatherzone Addict

Registered: 13/07/2001
Posts: 3983
Loc: Melbourne, Australia
Actually, there have been some big negative maximum temperature anomalies in tropical/subtropical regions in really wet months. January 1974 (Australia's wettest month on record) had big areas with maximum temperature anomalies below -6, especially in outback Queensland.

As for the alpine minimum temperatures - lining up with the likes of Kiandra and Cooma, I'd expect that a valley floor site at 1280m would have a mean minimum around -3. Higher than that if the local topography isn't quite as favourable. (Thredbo Village site, incidentally, is a little off the valley floor).

Also following up, the Riverina (and adjacent bits of northeast Victoria) is one area where the 1939 records mostly still stand. As of the start of 2009, 1939 was the benchmark heatwave over most of mainland southeast Australia, but the 1939 records have been progressively broken in most other areas over the last decade - starting with Black Saturday in most of Victoria, whilst this January's heatwave broke most of the remaining 1939 records in SA. (By the way, the old Wagga site was in town - Kooringal was where the rainfall-only site ended up after it stopped doing temperatures - but the move to the airport doesn't make a huge difference for maximum temperatures; different story for minima).

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#1501515 - 02/07/2019 07:08 Re: NSW Day to Day Weather - January to July 2019 [Re: Blair Trewin]
Adaminaby Angler Offline
Weather Freak

Registered: 26/03/2018
Posts: 375
Loc: Anglers Reach NSW; 1,290 m AMS...
Righto, pardon me for the "far below average" statement, Blair; it was well below, but not far below as I had claimed—should've chose my wording better.

Regarding the valley floor site minima, I am situated at what appears to be amongst the highest, hilliest properties in the Lake Eucumbene regional; the coldest air sinks downwards to the lake shoreline itself (in the valley), i.e. Old Adaminaby township, Anglers Reach Caravan Park/village, and especially Providence Portal, the lattermost of which can be up to 3° C cooler than me in minima. However, my maximum temperatures are certainly cooler than the rest—based chiefly upon my records, 4.9° C is my average July maximum.

With your final statement regarding 1939, I wholeheartedly agree with you.
_________________________
“Below 40 degrees South, there is no law; below 50 degrees South, there is no rescue; below 60 degrees South, there is no hope; below 70 degrees South, there is no God.”

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#1501518 - 02/07/2019 08:24 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Eigerwand Offline
Weather Freak

Registered: 28/05/2012
Posts: 526
7 day forecast for CT’s and most of NSW is absolutely abysmal for this time of year. Noticed the highs currently ruining winter in SE/E Aus, form into one and drifts over Tas to end moving still further south and strengthens to 1041hpa... what the!?
Must surely be an unusual scenario for this time of year.

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#1501525 - 02/07/2019 09:38 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Jimi Offline
Weatherzone Addict

Registered: 15/03/2004
Posts: 1129
Loc: Killara
The next seven days are 19C or more which can't be that common.

We averaged 19.9C (Obs Hill) last July which was high (second hottest?). The last 9 days of the month were all above 19C - all above 20C in fact plus a 19.9C - but perhaps that's more likely at the end of the month than the start?

This next period looks more showery, last July was very dry with just 11.2mm recorded on two days.

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#1501527 - 02/07/2019 09:44 Re: NSW Day to Day Weather - January to July 2019 [Re: Eigerwand]
Adaminaby Angler Offline
Weather Freak

Registered: 26/03/2018
Posts: 375
Loc: Anglers Reach NSW; 1,290 m AMS...
Originally Posted By: Eigerwand
7 day forecast for CT’s and most of NSW is absolutely abysmal for this time of year. Noticed the highs currently ruining winter in SE/E Aus, form into one and drifts over Tas to end moving still further south and strengthens to 1041hpa... what the!?
Must surely be an unusual scenario for this time of year.

And that, precisely, is the very reason as to why winter maxima have been warmer across much of Eastern AU in the last decade, as well as drier and less snowy—not because of that particularly censored reason of which you are fed daily by the Settled™ panel.

But don't you worry, because I believe that very same panel will merely come up with another, even more cunning "theory" as to what drives the Southern Annular Mode...
_________________________
“Below 40 degrees South, there is no law; below 50 degrees South, there is no rescue; below 60 degrees South, there is no hope; below 70 degrees South, there is no God.”

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#1501530 - 02/07/2019 10:13 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Wave Rider Offline
Meteorological Motor Mouth

Registered: 27/01/2014
Posts: 7365
Very dry air here today with humidity of 20% and dew point -6°C which isn't too common here. Most places east of the divide have dew points well into the negatives, eg Moruya -12 DP with 13% humidity earlier today.
_________________________
The longer you wait for storms, the more you appreciate them.

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#1501531 - 02/07/2019 10:18 Re: NSW Day to Day Weather - January to July 2019 [Re: Wave Rider]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Originally Posted By: Wave Rider
Very dry air here today with humidity of 20% and dew point -6°C which isn't too common here. Most places east of the divide have dew points well into the negatives, eg Moruya -12 DP with 13% humidity earlier today.


Agree, very weird as we usually see this type of setup with dry westerlies - the very low DP's sure make the air 'fee'l colder than it is.

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#1501532 - 02/07/2019 10:21 Re: NSW Day to Day Weather - January to July 2019 [Re: Jimi]
Steve777 Offline
Meteorological Motor Mouth

Registered: 20/10/2011
Posts: 5027
Loc: Artarmon (Sydney North Shore)
Runs of 19+ maxima in Sydney in July are quite common. Last year's average July maximum at Sydney OH was the warmest on record, although minima, at 8.1, was spot-on the all years average. It was a sunny month with cold clear nights and mild to warm afternoons, no maximum below 16.

Regarding the path of the highs, you rarely see anything like the standard textbook Winter synoptic map with highs tracking across the continent around th latitde of Brisbane and Westerlies and cold fronts sweeping to the South. So far this Winter it's mostly looked something like this:



So WA is getting its traditional Winter rain-bearing Westerlies, but not the East.


Edited by Steve777 (02/07/2019 10:22)

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#1501534 - 02/07/2019 10:31 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Mcbobbings Offline
Weather Freak

Registered: 22/06/2018
Posts: 134
What is causing these massive high pressure systems?

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#1501537 - 02/07/2019 11:48 Re: NSW Day to Day Weather - January to July 2019 [Re: Mcbobbings]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Originally Posted By: Mcbobbings
What is causing these massive high pressure systems?


Hadley Cell migration - but what is causing that is the great unknown. Colder South Ocean SST's would be dragging the Hadley Cell down no doubt from its usual parking spot over central Aus?

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#1501540 - 02/07/2019 13:23 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
The outlook 5 days from tomorrow on look good for the coastal strip to amass some decent totals (from Windy):
EC - 10mm - 40mm from Batemans Bay --> Newcastle
GFS - 10mm - 30mm Bateman's Bay --> Newcastle

I note ACCESS R has more for the area Jervis Bay to Helensburgh with up to 50mm possible. Hopefully we see more then that smile


Edited by Kino (02/07/2019 13:23)

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#1501541 - 02/07/2019 14:31 Re: NSW Day to Day Weather - January to July 2019 [Re: Adaminaby Angler]
Eigerwand Offline
Weather Freak

Registered: 28/05/2012
Posts: 526
Originally Posted By: Adaminaby Angler
Originally Posted By: Eigerwand
7 day forecast for CT’s and most of NSW is absolutely abysmal for this time of year. Noticed the highs currently ruining winter in SE/E Aus, form into one and drifts over Tas to end moving still further south and strengthens to 1041hpa... what the!?
Must surely be an unusual scenario for this time of year.

And that, precisely, is the very reason as to why winter maxima have been warmer across much of Eastern AU in the last decade, as well as drier and less snowy—not because of that particularly censored reason of which you are fed daily by the Settled™ panel.


But don't you worry, because I believe that very same panel will merely come up with another, even more cunning "theory" as to what drives the Southern Annular Mode...



There are numerous explanations as to why we appear to be seeing an increase in the area under the influence of the sub tropical jet and a warming planet is one of them. I would suggest making some attempt to understand the theories put forward rather than suggesting such theories that do indeed correspond with documented observations are all part of some kind of conspiracy.

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#1501542 - 02/07/2019 14:49 Re: NSW Day to Day Weather - January to July 2019 [Re: Eigerwand]
Jac0b Offline
Weather Freak

Registered: 17/12/2018
Posts: 144
Originally Posted By: Eigerwand
Originally Posted By: Jac0b
Definitely, the continental climates can deviate much more from their average due to having no ocean buffer. February 2019 had average monthly temperatures about 15°C below average in some towns across western Canada and northwestern USA. That would never occur here. Likewise, some months, e.g. May 1934 or March 2012 were over 10°C above average in parts of the Midwest USA.

In Australia a monthly mean that deviates even by 3°C is significant, whereas in the continental climates it's normal.


Indeed. I can imagine the variance in such data that would be observed in a small sample of months in such extreme climates would be problematic. But of course if there is some kind of background 'climate', get enough years together and like you mentioned, the variances should swing both ways thus giving some idea of what can be considered average and from there you can get some idea of what are typical and atypical months whilst taking into account that it takes a greater temperature deviation to correspond to a statistically significant anomaly.

In the case of Australia without the extremes of such continentality, off the top of my head as per the central limit theorem, I'd roughly estimate the level of significance for temperature anomalies around much of Australia to be something like:

+or- 1.2C = to 1standard deviation (sd) from the mean, (68% of months to fall within this range),

+or- 2.4C = to 2sd (95% of months to fall within this range) and,

+or- 3.6C = to 3sd's (99% of months to fall within this range).

From a statistical point of view, the trouble we seem to have in Australia when it comes to identifying the true mean, is that we appear to have a moving average. This is illustrated by the imbalance in frequency of months with anomalies of 3 to even 5C above average, yet very few months where the anomalies have gone the other way by a SIMILAR magnitude.

Very important that, the central limit theorem when discussing climate averages..


So the monthly temp anomalies in Australia would resemble a sort of "skewed" normal distribution. I wonder if anyone has actually taken the time to graph it for a few long record stations and see what actually comes out. I would also think that the distributions for the spring months would have the largest standard deviations compared to other months.

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#1501543 - 02/07/2019 15:04 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Eigerwand Offline
Weather Freak

Registered: 28/05/2012
Posts: 526
Yeah, definitely seems to be skewed to the right.

Be very interesting to see what would come of it. For sure there’d be difference in the amount of variance and therefore the size of the sd typical to a given month. Particularly in regions like Blair mentioned such as inland QLD where something like the presence or absence of a La Nińa (I assume that’s what produced the anomaly he referred to) can produce markedly different conditions from year to year.

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#1501545 - 02/07/2019 16:12 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Blair Trewin Offline
Weatherzone Addict

Registered: 13/07/2001
Posts: 3983
Loc: Melbourne, Australia
I've done a lot of work on shape/skewness of daily temperature distributions (it was a big chunk of my PhD thesis), less so with monthly. Big variations from place to place - at the daily timescale, you find strongly positively skewed distributions for spring and summer maximum temperatures around the coasts outside the tropics, and strongly negatively skewed in a lot of northern and central Australia.

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#1501550 - 02/07/2019 18:11 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
Wave Rider Offline
Meteorological Motor Mouth

Registered: 27/01/2014
Posts: 7365
Well today was nothing short of amazing weatherwise. We reached 21°C with almost no wind all day and really dry air.
_________________________
The longer you wait for storms, the more you appreciate them.

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#1501551 - 02/07/2019 18:20 Re: NSW Day to Day Weather - January to July 2019 [Re: Wave Rider]
Homer Offline
Meteorological Motor Mouth

Registered: 16/06/2007
Posts: 6407
Loc: Dural
Originally Posted By: Wave Rider
Well today was nothing short of amazing weatherwise. We reached 21°C with almost no wind all day and really dry air.


Yep. It was a gorgeous winters day.
Bit of high cloud keeping things cool to cold early, but then it just warmed up nicely.
Pretty nice for this time of year.

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#1501552 - 02/07/2019 18:49 Re: NSW Day to Day Weather - January to July 2019 [Re: Eigerwand]
Adaminaby Angler Offline
Weather Freak

Registered: 26/03/2018
Posts: 375
Loc: Anglers Reach NSW; 1,290 m AMS...
Originally Posted By: Eigerwand
There are numerous explanations as to why we appear to be seeing an increase in the area under the influence of the sub tropical jet and a warming planet is one of them. I would suggest making some attempt to understand the theories put forward rather than suggesting such theories that do indeed correspond with documented observations are all part of some kind of conspiracy.

Slightly correct; Co2 (not necessarily a warming planet), is one of myriads of factors—i.e. not the foremost driving factor of temperature, especially when it's in fact the Co2 that follows temperature, and not the other way round, as proven by the ice-core and botanical stomata records. Farthermore, when glancing back into Earth's paleoclimatological history, you will find that periods whereby Co2 was markedly high, the temperature was markedly low (and vice-versa); thereby mercilessly sundering the over-renowned theory.

Remember: I accept the scientific law that Co2 is one of many factors contributing to climate, but to so boldly state that it is the driving factor, is beyond absurd. Now, I'm not directly accusing you of uttering such a statement, but merely calling it out.
_________________________
“Below 40 degrees South, there is no law; below 50 degrees South, there is no rescue; below 60 degrees South, there is no hope; below 70 degrees South, there is no God.”

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#1501561 - 03/07/2019 00:38 Re: NSW Day to Day Weather - January to July 2019 [Re: Seabreeze]
deanh Offline
Weather Freak

Registered: 10/07/2006
Posts: 74
Loc: Campbelltown, Sydney
Random...

It's a shame that there isn't a better positioned weather station around the Campbelltown area. Doesn't it sit on bit of a hill at Mount Annan?

The temperature readings there seem pretty different compared to around the Ingleburn/Minto areas. Again tonight, there was already frost on cars before midnight, however Campbelltown is sitting around ~7°C. There are many mornings where there is thick frost, yet no sub-zero reading at the Campbelltown weather station.

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