Topic: Warmer than normal summer 2009/2010

[Harley Pearman]

Warmer than normal summer for 2009/2010

Following the success of the POAMA (Predictive Ocean Atmospheric Model for Australia) models to predict a warmer than normal spring for South East Australia, I have now looked at the POAMA models for the period December to February 2009/2010.

It should also be noted that the POAMA 1.5/2 is a program prepared by the CSIRO and is still at an experimental stage. It can be used to predict future average temperatures and rainfall patterns for Australia several months in advance.

Generally the POAMA Ensembles are suggesting a warmer than normal start to summer but as summer progresses into early 2010, the Ensembles suggest that average temperatures will return back to normal. In particular:-

December 2009

The POAMA Ensembles suggest a warmer than normal month especially for Eastern Australia and the East Coast of Australia. The Ensembles are suggesting average temperatures to be 1.5C to 2C above the long term average. The Ensembles also suggest that average temperatures will be 0.5C to 1C above average for much of the state of Victoria.

January 2010

The POAMA Ensembles suggest a warmer than normal month across Eastern Australia with average temperatures of 0.5C above average. Elsewhere the Ensembles suggest that average temperatures will return to normal with no clear view of whether temperatures will be above average or not.

February 2010

The POAMA Ensembles does not suggest any direction as to whether average temperatures will or will not be above the long term average.

As per the previous thread "Warmer than normal spring" any heatwaves, hot spells and unusual temperature extremes that may occur during the summer months could be described within this thread.

Harley Pearman

[Harley Pearman]

First burst of December heat arrives for parts of New South Wales

A burst of summer heat has arrived across large areas of New South Wales excluding the coastal fringe, South Coast south of Sydney and some southern inland areas of the state. The hottest locations at 3 pm for 7 December 2009 at various Bureau of Meteorology Weather Stations include:-

Upper Western (NSW) - Collarenebri and Lightning Ridge 42C, Brewarrina 41C. The 3 pm temperatures varied from 36C to 42C.
North West NSW - Mungindi and Walgett 42C and Gunnedah Airport 40C.
Central West NSW - Coonamble 40C. The 3 pm temperatures varied from 35C to 40C.
Hunter Valley away from the coastal fringe - Singleton 40C. Temperatures at Jerrys Plains and Maitland region varied from 38C to 40C.
Sydney Region - Temperatures across the inland suburbs reached 38C - 39C being Blacktown, Camden, Campbelltown, Penrith and Richmond.

Another hot day for 8/12/09 looms across many areas of the state. Even in Sydney for 8/12/09 but more so for the western suburbs, a forecast top of 38C to 40C is made for suburbs of Parramatta, Blacktown, Liverpool, Penrith and Richmond before a late cooler southerly change.

Harley Pearman

[Harley Pearman]

Summer heat for 8 December 2009 (NSW only)

Some significant summer heat occurred across New South Wales particularly north and east of the cold front that moved across the state. A top temperature of 43C occurred at Grafton, Gunnedah, Jerrys Plains, Mungindi and Walgett.

In particular, the peak temperatures at 3 pm for 8/12/09 taken from the various Bureau of Meteorology Weather Stations include the following:-

Upper Western and Western New South Wales - Brewarrina and Wanarring 42C and Cobar - 40C. The 40C temperatures occurred at places north of the cold front. To show the significance of the cool change, it was 22C at Broken Hill and 19C at Mildura at the same time.

North West Slopes (NSW) - Peak temperatures of 35C to 43C occurred. Gunnedah - 43C being the hottest location.

Central West NSW - 37C to 41C with Coonamble reaching 41C.

Northern River NSW - 43C at Grafton, 40C at Casino and 36C at Lismore. Generally areas away from the coastal fringe experienced a hot day.

In Sydney the heat was more limited to Penrith and Richmond. When checking the weather stations for the two localities via Weatherzone, it is noted that a peak of 38.7C occurred at Penrith at 3.30 pm and 38.5C occurred at Richmond at 3.20 pm. Peak temperatures started to cool after as the cool change approached. It still reached 33C to 35C across Western Sydney outside Penrith and Richmond but the highs of 39C and 40C were not reached. The cool change has now gone through and conditions at 8 pm are cloudy but pleasant.

Harley Pearman

[Harley Pearman]

Heat surges across Victoria and inland New South Wales 16/12/2009

So far this December there have been few hot spells however a surge of heat has been making its way across Victoria and inland New South Wales ahead of the next cooler change. For inland New South Wales, some high maximum temperatures for the 3 pm readings for 16/12/2009 (Bureau of Meteorology Weather Stations) include:-

North west and west - Peaks of 39C to 42C common with 42C at Wilcania and Ivanhoe (The usual hot spots).
Central West - Peaks of 38C to 41C common with 41C at Nyngan.
Riverina - Peaks of 38C to 41C common with Hillston at 41C.
South West Slopes - Peaks of 37C to 40C with Quandialla at 40C.

Much of the heat stayed west of the Great Dividing Range although it did reach 38C at Scone, 37C at Singleton (Hunter Valley) and 36C at Penrith in Western Sydney (3 pm readings). The top temperature for Penrith in Western Sydney was 36.7C at 4 pm.

Much of inland Victoria experienced a hot day with peaks of 38C and 40C common right across the north of the state. Mildura, Ouyen and Swan Hill had 3 pm maximums of 40C to 41C and it was even 40C at Warrnambool in south west Victoria. The next cool change progressing across the state will result in a cooler air mass and cooler conditions for the 17/12/09.
 
Melbourne had a 3 pm maximum temperature of 38C with a 4 pm peak of 39C making it the hottest day so far this December in this city.

Adelaide in South Australia had a 3 pm temperature of 41C.

Harley Pearman

[Harley Pearman]

A hot day for 17 December 2009 (New South Wales only)

In addition to some significant weather events for the 17/12/2009, some significant maximum and minimum temperatures occurred. Furthermore Moruya on the New South Wales South Coast saw some unusual temperature fluctuations worth a mention.

I have looked at maximum and minimum temperatures using the 3 pm readings at various Bureau of Meteorology Weather Stations across New South Wales. Generally there were some warm temperatures both night and day and much of New South Wales was on the receiving end of a hot uncomfortable day. The only regions to escape the heat was the Northern Rivers, Mid North Coast, Southern Alps of the state and the coastal strip right on the coast.

Western New South Wales - Broken Hill had a minimum overnight temperature of 30C with 29C at Fowlers Gap and 27C at Cobar to 43C at Ivanhoe and 42C at White Cliffs.

Central West - A minimum of 29C at Nyngan and 27C at Parkes, Peak Hill and Trangie to 43C at Forbes and 42C at Nyngan.

Riverina - A minimum of 24C at Hay to 43C at Lake Cargelligo and 42C at Hay.

South West Slopes - A minimum of 25C at Grenfell to 43C at Temora and 42C at Gundagai.

Hunter Valley - The warmest minimum temperature was 21C at Murrurundi Gap and the maximum was 41C at Jerry's Plains and Maitland but on the coast, 27C at Nelson Bay. The heat did not make it to the coastal strip.

South Coast - Maximum temperatures reached 43C at Nowra but only 26C at Bellambi.

In Sydney's West, a maximum of 43C occurred at Badgereys Creek with other inland suburbs such as Parramatta, Blacktown, Liverpool, Penrith and Richmond all scoring a top of between 41C and 42C.

Coastal Sydney missed the heat and the minimum and maximum temperature range was 21C to 30C at Sydney Observatory Hill.

Additionally the weather station at Moruya Airport - Station Number ID 069148 Latitude 35.9S and Longitude 150.14E (Elevation 4 metres) recorded some unusual temperature fluctuations during the day based on the direction of the wind. So unusual, it is worth a mention in this thread.

11 am - 39C - Winds were N
11.22 am - 33.9C - Winds were ENE.
11.26 am - 39.4C - Winds were N.
11.28 am - 33.1C - Winds were NNE.
11.47 am - 28.1C - Winds were NE.
12 Noon - 29.7C - Winds were NE.
1 pm - 26.1C - Winds were ENE.
1.25 pm - 31.2C - Winds were E
1.48 pm - 37.4C - Winds were W.
1.57 pm - 40.3C - Winds were NW.
4 pm - 42C - Winds were WNW.


Harley Pearman

[Mathew Townsend]

I don't believe January and February will be hot ones due to large amount of precipitation surge from the tropics. Even according to the satellite and GFS showing vast amounts of rainfall across the nation including 95% covering NSW!

[Harley Pearman]

December average temperatures 2009 for New South Wales

Attached is a breakdown of monthly average maximum and minimum temperatures for 7 weather stations across Sydney for the month of December. Surprisingly the temperatures were close to that expected by POAMA (Predictive Ocean Atmospheric Model for Australia) in which they were above the long term average. The daytime anomalies were greater for the inland suburbs than that experienced closer to the coast. Generally a warmer than expected December occurred across the city day and night.

The same occurred across the state of New South Wales. Barring a few exceptions, average temperatures statewide for the month of December were mostly above average and within or close to that expected by POAMA. Summing up December average temperatures were within or close to expected computer models as shown.

The data and plots are derived from Bureau of Meteorology weather station sites (Sydney), Weatherzone for monthly averages and Water and the Land for average monthly temperature plots.

Harley Pearman  

[Richary]

Harley I heard reports the other day on the news that I didn't post because I figured you would have better access to the stats. Not all east coast but anyway.

Apparently Alice Springs recorded their driest year on record, with a total of 77mm. The previous low was 83 from memory, with an average year bringing 277mm. This is despite any fallout from the recent low caused by TC Laurence.

SA has also recorded it's 2nd hottest yest since records began as well with average temperatures. Obviously in different areas has been a lot of local variation as well, with some very dry areas and others getting massive downpours on the east coast. Extreme to extreme, the rains in the north west of NSW that were initially welcomed to break the drought have now turned into major flooding. It sure is a land of extremes this one.

[Harley Pearman]

January heatwave / hot spell 7 to 13 January 2010

I have prepared a table below for some towns and cities across Victoria and New South wales showing the maximum and minimum temperatures recorded for the period. During this period a significant hot spell gripped South Eastern Australia although looking at the data for numerous weather stations, the heat was confined more towards the inland regions rather than the coastal areas. The heat was most intense across Northern Victoria and inland Southern and South West New South Wales.

I have added in temperature readings for Prospect and Penrith (Western Sydney)to provide a comparison during the weather event for Western Sydney and inland regions. Some daily readings were high but in addition, some night time readings were also well above the average expected.

The data is derived from the weather stations with average January temperatures for the towns and cities obtained from Weatherzone 15/1/2010.


Harley Pearman

[Harley Pearman]

Western Sydney hot spell - 20 to 23 January 2010

During the period of 20 to 23 January 2010, Western Sydney experienced a hot spell spanning 4 days. I have prepared a table showing 8 weather stations including maximum and minimum temperatures for the period as well as average temperatures for the month of January. It should be noted that some Western Sydney weather stations and suburbs recorded 3 days where the peak daily temperature reached 40C eg Penrith, Camden and Campbelltown with Prospect (Blacktown) and Richmond not too far behind. Is this a true heatwave?

I have not been able to find a true Australian Definition of a heatwave. There is one for Adelaide (SA) being 5 or more days where maximum temperatures exceed 35C including 3 days where the maximum temperature reaches or exceeds 40C (Source BOM). Reading the book "Extreme Weather" by H Michael Mogil 2007 (Page 211) it seems that in SE Queensland a heatwave may be defined as threshold temperatures within the top 5% of daily maximums for a 3 day period. Perhaps there ought to be a definition and if one exists for Western Sydney or Sydney then unfortunately I have not been able to find it.

A few interesting weather phenomena to note from 23/1/2010 in Sydney:

In Sydney City, the temperature was 27.3C at 2 am and 30.5C at 7.30 am (BOM weather station data 23/1/10).

The cool change reached Sydney being Kurnell at approximately 3.03 pm and had reached Sydney Airport by 3.18 pm. The temperature at the airport was 40.7C at 3.11 pm. By 3.18 pm it was 25.3C in south easterly winds (BOM Weather station data for 23/1/2010).

At Sydney Olympic Park, the temperature was 42.1C at 3.30 pm. By 3.35 pm, it plunged to 34C (8C plunge in 5 minutes following the change) - BOM Weather Station data 23/1/2010.

The cool change reached Blacktown where I live at 3.59 pm dropping the temperature substantially from 42C.

The table referred to is attached below. The data is derived from the weather stations being the maximum and minimum temperatures (Bureau of Meteorology) and Weatherzone (Average temperatures for January).

Harley Pearman

[Harley Pearman]

A warmer than normal January 2010 (New South Wales)

Please find attached a table referencing the average temperatures for Sydney for the month of January 2010. January 2010 was warm across the whole of Sydney with average daytime and night time temperatures being above average again. I have combined the data from the weather stations via Bureau of Meteorology and Weatherzone to produce the table.

Day time maximum temperature

Except for the northern inland, all parts of the state of New South Wales experienced a warmer than normal January. Typically day time maximum temperatures fell in the range of 1C to 3C above the average. It is noted that the south west of the state centred on Albury, Griffith, Canberra and Wagga Wagga experienced a hot January and temperature anomalies were 3C to 4C above the long term average. Generally coastal areas had maximum daytime temperatures of between 1C to 3C above the long term average. This is shown in the first plot produced at the Bureau of Meteorology Land and Water site attached below (January 2010).
 
Night time minimum temperatures

All parts of the state (New South Wales) experienced a warmer than normal month with regard to minimum overnight temperatures. Typically minimum average temperatures fell in the range of 0C to 3C above average although the south east inland experienced the greatest anomaly in which minimum temperatures were 2C to 3C above average. The north west inland experienced minimum temperatures of 1C to 2C above average and similar readings occurred along much of the coast except for the north coast.This is shown on the second plot below produced on the Bureau of Meteorology Land and Water site (January 2010).


Harley Pearman

[Harley Pearman]

February 2010 weather data for Sydney (A warmer than Normal February occurred)

Following the trend from November 2009, the month of February 2010 was warmer than normal across the city. Both night time and daytime average temperatures were again above average.

The attached table below shows this. The data is obtained from various weather stations in the Bureau of Meteorology network. I have also added rainfall only because February was a wet month across the city. In addition to a warmer than normal February, it was also a wet month. Hence a warm wet February has just been concluded.

It is noted that no weather station across the city recorded a maximum daily temperature exceeding 37.9C anytime during the month. Sydney Olympic Park recorded 37.9C, Penrith 37.1C and Sydney recorded 37.8C on the 12/2/2010. This was the hottest day of the month across Sydney.

Overall though, Sydney has generally enjoyed a warmer than normal summer in accordance with the initial statements made earlier in this thread.

The table referred to is attached below.


Harley Pearman

[Harley Pearman]

New South Wales. A warmer than normal February for some / A cooler February for Others

The month of February saw contrasting temperature anomalies for the state of New South Wales best summarised below. In addition, when analysing the data from numerous weather stations, it becomes apparent that there were no significant heatwaves. The maximum daily temperatures occurred early in the month which included (Sydney excluded):-

Wilcania - 38.7C on 11/2/10. Albury Airport - 38.2C on 1/2/10. Fowlers Gap - 37.7C on 11/2/10
Walget - 37.6C on 13/2/10. Wagga Wagga - 37.3C on 1/2/10. Temora - 36C on 1/2/10.

These are some of the maximum daily temperatures for the month that can be found. Cloud cover and rain across large areas of the state appears to have moderated daytime maximum temperatures. When reference is made to the initial POAMA Models, the model initially did not specify as to whether a warmer than normal month would or would not occur. February was a month in which a mixed bag of anomalies occurred.  

A summary of the temperature anomalies is provided below.
 
Daytime maximum temperatures:

There were wide variations that is best summarised by:-

- North West NSW - 3C to 4C below average.
- Western NSW - 0C to 3C below average.

Murray Darling (Murray River) Hume Reservoir to Mildura region:

A warmer than normal month of 0C to 2C above the average. I travelled into this region during early February and noted that while much of NSW was experiencing cooler temperatures, this region was still experiencing maximum daily temperatures of 34C to 36C with less cloud cover.
 
- Northern NSW - Minus 1C to minus 4C (Below average).
- Sydney to Newcastle - 1C to 3C above the long term average.
- North Coast - 0C to 1C (Average to slightly above the long term average).
- South Coast - 0C to 1C (Average to slightly above the long term average).

Overnight minimum temperatures:

As shown on the second plot, generally the nights were warmer than average across most of the state except for the North West inland. The greatest anomaly occurred across the inland south west of the state where the nights were 2C to 4C above average. In contrast, across the inland north west of the state, the nights were 0C to 1C below average.

The plots referred to above are attached below. They have been produced on the Bureau of Meteorology "Water and the Land" site for February dated 5/3/2010.


Harley Pearman