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Autumn charts. Now time for winter...

592fb3f663290_Autumn2017Decile.thumb.gif.9fc773afc81c270c8ab73da240bd38a9.gif592fb3e250576_Autumn2017trend.thumb.png.c0a6cf9986206bc2b0fdf8e821b399be.png

Mean anomaly ( 1961-90 ):

March:  +1.7  Third warmest on record

April:  +0.1

May:  +0.7

592fb4087c431_Autumn2017Rainfall.thumb.gif.7705d61d696c8acd1848d37af560c3df.gif

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Dominant high pressure in charge across most of a Australia for quite some time now with no major change in the medium term. Widespread below average temperatures at night away from the coast, and daytime temperatures seem to be a bit below normal too. Maybe we'll finish up with a dry, colder than average month to start winter nationally, but too early to tell right now.

Tasmania is a bit milder being on the bottom flank of the high so nothing too cold here, more like late autumn weather really, cool and calm.

This weekend is the traditional opening of the ski season on the mainland,  some of the main resorts have opened already catering for minor activities, like snow play, sledding and some piste runs. The snow guns have done most of the work, churning it out in the cold and frosty conditions. There was about 20cm of natural snow cover at the end of May at high range, but that's all. There are no snow bearing fronts on the horizon,  they would be wanting something to show up by the end of the month I think.     

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Alice Springs currently has a June average minimum of -0.8c to the 9th, the running average by the 16th will be close to -1.0c...a full 6 degrees colder than average for June for central Australia.

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6 hours ago, Styx said:

This weekend is the traditional opening of the ski season on the mainland,  some of the main resorts have opened already catering for minor activities, like snow play, sledding and some piste runs. The snow guns have done most of the work, churning it out in the cold and frosty conditions. There was about 20cm of natural snow cover at the end of May at high range, but that's all. There are no snow bearing fronts on the horizon,  they would be wanting something to show up by the end of the month I think.     

There are some signs of frontal activity towards the end of the month. EPS Control suggests the period beyond the 20th to be cold for SE Australia. But too early to call...

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synoptic.thumb.png.c5a5b608a33952da1a25d436edd1075d.png

The unusually dry start to winter in southern Australia is now breaking records, notably for consecutive days without rain for a winter season, and low or zero rainfall up to this date in June. A stubborn belt of high pressure stretches from the Indian Ocean out to the Tasman Sea. This time of year is normally associated with Southern Ocean fronts bringing showers or rain to Australia's south.

Hobart has just notched up its 17th consecutive rain free day which is a winter record, the old record is 16 recorded only twice, in records dating back to 1893. We might even reach the giddy number of 20 which would be astonishing, matching historically long dry spells, the vast majority which have been recorded in summer!

I can not believe what the temperature is doing either. With no cold fronts cutting through and winds persistently from the west or milder north west, the average is sky high. We are nearing an average maximum for June of 15c, almost 1 degree higher than the previous record, and 2.5C up on the recent 30 year average. 

On the mainland, the mean maximum is moving up now, but is closer to the average, but minima is generally below or well below under calm, high pressure skies.

There looks like a breakdown is on the cards soon, frontal activity bringing more seasonal wintry type changes. Hopefully some snow for the mountains. Up until then we have a bit of history in the making.

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This map looks quite remarkable. I don't know how this June stacked up in comparison to historically dry starts to winter on the raw numbers yet, but it will be interesting to find out when those figures are released tomorrow.

5956189f07a86_Junerainfall2017.thumb.gif.ccc872a052cdf233123e65c751659b95.gif

Meantime temperatures are forecast to plummet across southern and south eastern Australia tonight. It follows cold dry air in the wake of a cold front last night that didn't produce much in the way of showers or elevated snow. The first -10c of the season is possible in Tasmania and Hobart city may get close to rare freeze. Melbourne will too which is really rare for them. And Canberra is heading for a -7c!

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The standout low temperature last night was -8.7c in Canberra. That was the third coldest July temperature recorded in the capital. In Tasmania, the low was -9.7c in the Great Lake region which is in the central part of the island. Hobart city had 1c, it is becoming increasingly rare to hit a zero ( it has only happened three times this century ), I suspect a rapid increase in sea surface temperature off the east coast could be mostly responsible for that. That also poses problems for snow events which have always been marginal. It won't be as cold tonight.

-------------------------

Canberra's lowest July temperatures on record ( records since 1939 )

1......-10.0......11th 1971

2......-8.9........13th 1971

3......-8.7........ 1st 2017

4......-8.6.........3rd 1971

5......-8.4.........12th 1971

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In the north weather for the dry season (May to September) has been drier than average and temperatures marginally above. Apart from the east coast, rainfall in the northern dry season is almost negligible so slight changes can statistically seem very large.

For Darwin (July figures 5 days only):

Minimums
May av. 22.2C
May2017 22.6C

Jun av. 19.9C
Jun2017 20.0C

Jul av. 19.3C
Jul2017 22.1C

Maximums
May av. 32.0C
May2017 32.9C

Jun av. 30.7C
Jun2017 31.3C

Jul av. 30.6C
Jul2017 32.5C

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A nice snow treat for Western Australia!  According to the BOM, light snow will settle on the Stirling Ranges ( 1095m )  about twice a year.  It is 500km/310miles south of Perth. I think it's the only mountain range in WA that ever gets any. Seems to be a bit of a sport for the snow starved folk in the west to head up there whenever it is forecast.  More snow possible this afternoon and tonight as another cold front crosses south-west Western Australia.  

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On 5 July 2017 at 21:13, Styx said:

A nice snow treat for Western Australia!  According to the BOM, light snow will settle on the Stirling Ranges ( 1095m )  about twice a year.  It is 500km/310miles south of Perth. I think it's the only mountain range in WA that ever gets any. Seems to be a bit of a sport for the snow starved folk in the west to head up there whenever it is forecast.  More snow possible this afternoon and tonight as another cold front crosses south-west Western Australia.  

Good site for info on past WA snowfalls

http://www.feargod.net/wa-snow2a.php

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^ An interesting list which shows elevated towns in the south west of Western Australia ( near 300m ) have had snow on the ground in the past - but it's been 25 years now since that last happened. That is typical of the trend throughout the south and east of Australia as well, a big drop off of noteworthy snow events at low levels, and prolonged cold air masses.   

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Here is the latest snow depth reading from the upper slopes of the Snowy Mountains in southern New South Wales, Australia's tallest mountain range. Snowy Hydroelectricity Limited has been taking official weekly measurements of snow depth at Spencers Creek ( 1830m ) since 1954, to determine melt inflow into the dams during spring. It is 1 mile from Australia's largest ski field, so it's a good guide to the health of the ski industry in general, and its future, which unfortunately doesn't look particularly good going by the long term trends of season peak... and shortening seasons.

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*The lowest peak snow depth was in 2006 with 85.1cm. That record looks safe this year, there's another 30cm+ snow forecast this week, nothing much will melt before the next measurement.

*The highest peak snow depth was in 1981 with 361cm.

*Last year's peak snow depth was on October 6th, the latest time on record, bucking the clear trend of earlier melt seasons.

 

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